Tuesday, October 7, 2025

The Uncontrolled Seizure: Navigating Status Epilepticus and its Mimics

A Comprehensive Review for the Critical Care Postgraduate

Dr Neeraj Manikath , claude.ai

Abstract

Status epilepticus (SE) represents one of the most challenging neurological emergencies encountered in intensive care units, with mortality rates ranging from 10-40% depending on etiology and treatment response. This review provides an evidence-based approach to the diagnosis and management of SE beyond first-line benzodiazepine therapy, explores the complexities of refractory and super-refractory SE, addresses the often-missed diagnosis of non-convulsive SE, and highlights important mimics including psychogenic non-epileptic seizures and post-anoxic myoclonus. Special attention is given to autoimmune encephalitis as an increasingly recognized cause of new-onset refractory status epilepticus (NORSE). Clinical pearls, diagnostic pitfalls, and practical ICU management strategies are woven throughout to enhance bedside decision-making.

Keywords: Status epilepticus, refractory seizures, non-convulsive status epilepticus, continuous EEG monitoring, autoimmune encephalitis, psychogenic non-epileptic seizures

Introduction

Status epilepticus is classically defined as continuous seizure activity lasting more than 5 minutes or recurrent seizures without return to baseline consciousness. This operational definition, updated by the International League Against Epilepsy (ILAE) in 2015, recognizes two critical time points: t₁ (5 minutes for convulsive SE, 10 minutes for focal SE with impaired consciousness), when treatment should be initiated, and t₂ (30 minutes for convulsive SE), beyond which long-term consequences including neuronal death become likely.[1,2]

The incidence of SE ranges from 10-40 per 100,000 population annually, with a bimodal distribution affecting children and the elderly disproportionately.[3] Despite advances in antiseizure medications (ASMs), approximately 30-40% of cases progress to refractory SE (RSE), defined as seizures continuing despite adequate doses of a benzodiazepine and at least one appropriate second-line ASM.[4] The management of SE has evolved significantly, yet controversies persist regarding optimal second-line agents, anesthetic protocols, and the recognition of non-convulsive presentations.

This review adopts a practical, evidence-based approach tailored to the critical care physician managing these complex cases in real-time.

Beyond Benzodiazepines: The Evidence for Fosphenytoin, Valproate, and Lacosamide

The Second-Line Dilemma

Once benzodiazepine therapy (lorazepam 0.1 mg/kg IV or diazepam 0.15-0.2 mg/kg IV) fails to terminate seizures, clinicians face a critical decision point. For decades, phenytoin or its water-soluble prodrug fosphenytoin dominated as the default second-line agent. However, landmark trials have challenged this paradigm and expanded our armamentarium.

The ESETT Trial: Equipoise Established

The Established Status Epilepticus Treatment Trial (ESETT), published in 2019, randomized 462 patients with benzodiazepine-refractory SE to receive fosphenytoin (20 PE/kg), valproate (40 mg/kg), or levetiracetam (60 mg/kg).[5] The primary outcome—seizure cessation by the end of infusion with improved responsiveness at 60 minutes—occurred in 45-47% of patients across all three groups, with no statistically significant differences. Crucially, safety profiles were comparable, refuting earlier concerns about valproate-induced hepatotoxicity or thrombocytopenia in acute settings.

Pearl: ESETT definitively established that no single second-line agent is superior for benzodiazepine-refractory SE. Choose based on patient-specific factors rather than dogma.

Fosphenytoin: The Traditional Workhorse

Fosphenytoin (15-20 PE/kg IV at 100-150 PE/min) offers the advantage of decades of clinical experience and potent sodium channel blockade.[6] Its pharmacokinetics are predictable, and it achieves therapeutic levels rapidly.

Oyster: Beware hypotension and cardiac arrhythmias, particularly in elderly patients or those with pre-existing cardiac disease. Fosphenytoin causes cardiovascular adverse effects in up to 10% of patients, necessitating cardiac monitoring during infusion.[7] The "purple glove syndrome" associated with phenytoin is avoided, but extravasation of fosphenytoin can still cause tissue injury.

Hack: If fosphenytoin is unavailable or contraindicated (heart block, bradycardia), proceed directly to valproate or levetiracetam rather than delaying therapy. Time is brain in SE.

Valproate: Broad-Spectrum Efficacy

Valproate (40 mg/kg IV at 6-10 mg/kg/min, maximum 3000 mg) possesses multiple mechanisms of action: enhancing GABAergic neurotransmission, blocking voltage-gated sodium channels, and modulating T-type calcium channels.[8] This broad-spectrum activity theoretically makes it attractive for SE of unknown etiology.

Pearl: Valproate is particularly useful in patients with generalized epilepsies, those with contraindications to phenytoin (cardiac disease, history of Stevens-Johnson syndrome), or when hepatic enzyme induction is undesirable (e.g., patients on oral contraceptives, warfarin, or chemotherapy).

Oyster: Absolute contraindications include known mitochondrial disorders (e.g., POLG mutations), urea cycle disorders, and hepatic failure. Relative contraindications include pregnancy (teratogenicity risk), thrombocytopenia, and pancreatitis history. The ESETT trial found valproate safe in acute use, but avoid in patients with pre-existing hepatic dysfunction or coagulopathy.[5]

Hack: Valproate loading causes less hemodynamic instability than fosphenytoin and can be given faster, making it advantageous in hemodynamically unstable patients requiring rapid seizure control.

Levetiracetam: The New Favorite

Levetiracetam (60 mg/kg IV over 10-15 minutes, maximum 4500 mg) has emerged as many intensivists' preferred second-line agent due to its exceptional safety profile, lack of drug interactions, and absence of cardiac or hepatic toxicity.[9] Its mechanism involves binding to synaptic vesicle protein 2A (SV2A), modulating neurotransmitter release.

Pearl: Levetiracetam is the safest second-line option for elderly patients, those with multiple comorbidities, or when the diagnosis is uncertain (e.g., concern for psychogenic seizures). It can be administered rapidly without cardiac monitoring in most cases.

Oyster: Emerging data suggest levetiracetam may be less effective than traditional agents in specific populations. A post-hoc analysis of ESETT showed lower seizure cessation rates with levetiracetam in children and in patients with prior benzodiazepine administration outside the hospital.[10] Additionally, some retrospective studies suggest lower efficacy in established SE compared to fosphenytoin or valproate, though prospective validation is lacking.

Hack: If levetiracetam fails as second-line therapy, adding a second agent with a different mechanism (fosphenytoin or valproate) is reasonable before escalating to anesthetic agents. This "dual second-line" approach lacks high-quality evidence but represents common practice.

Lacosamide: The Emerging Alternative

Lacosamide, while not included in ESETT, has gained traction as a second- or third-line agent for SE. It enhances slow inactivation of voltage-gated sodium channels, a mechanism distinct from phenytoin's fast inactivation.[11]

Evidence Base: A systematic review of 11 studies (n=524 patients) found lacosamide terminated SE in approximately 60% of cases when used as second-line or adjunctive therapy, with a favorable safety profile.[12] The recommended loading dose is 200-400 mg IV over 15 minutes, followed by maintenance dosing of 200-400 mg/day divided twice daily.

Pearl: Lacosamide is particularly useful when fosphenytoin has failed or is contraindicated, as its distinct mechanism may provide additive benefit. It's also advantageous in patients already taking phenytoin chronically (avoid loading a patient already at therapeutic levels).

Oyster: Cardiac conduction abnormalities (PR prolongation, AV block) occur in approximately 1-5% of patients. Obtain a baseline ECG and avoid in patients with second- or third-degree heart block unless a pacemaker is present.[13]

Hack: In elderly patients or those with cardiac history, infuse lacosamide over 30-60 minutes rather than 15 minutes to minimize cardiac risk while still achieving therapeutic levels faster than oral administration.

Practical Algorithm for Second-Line Therapy

Clinical Scenario-Based Selection:

Young, healthy patient with unknown SE etiology: Levetiracetam (safest, broad-spectrum)
Known generalized epilepsy or myoclonic features: Valproate (broad-spectrum activity)
Cardiac disease or hemodynamic instability: Levetiracetam or valproate (avoid fosphenytoin)
Hepatic disease or coagulopathy: Levetiracetam or fosphenytoin (avoid valproate)
Heart block or significant bradycardia: Valproate or levetiracetam (avoid fosphenytoin and lacosamide)
Pregnancy: Levetiracetam or fosphenytoin (avoid valproate)
Suspected mitochondrial disease: Fosphenytoin or levetiracetam (avoid valproate)

Pearl: Don't delay second-line therapy while deliberating. Any appropriate agent given promptly is superior to the "perfect" agent given late. If seizures persist beyond 5 minutes of second-line agent completion, move immediately to third-line or anesthetic therapy.

Refractory & Super-Refractory Status Epilepticus: Anesthetic Doses and the ICU Pipeline

Defining the Beast

Refractory Status Epilepticus (RSE) is defined as seizures continuing despite adequate doses of a benzodiazepine and one appropriate second-line ASM (typically for more than 30-60 minutes of treatment).[14] Approximately 30-40% of SE cases become refractory.

Super-Refractory Status Epilepticus (SRSE) represents the most challenging scenario: SE continuing or recurring 24 hours or more after initiation of anesthetic therapy, including cases that recur upon anesthetic weaning.[15] SRSE occurs in 10-20% of RSE cases and carries mortality rates of 30-50%.

Anesthetic Agents: The ICU Armamentarium

Once SE is deemed refractory, continuous IV anesthetic agents with continuous EEG monitoring become necessary. The primary goals are seizure suppression and preventing secondary brain injury while identifying and treating the underlying cause.

Midazolam: First Among Equals?

The RAMPART trial established midazolam as effective for prehospital SE,[16] and its use has expanded to RSE management. Loading doses range from 0.2 mg/kg (up to 20 mg) followed by continuous infusion starting at 0.1-0.2 mg/kg/hr, titrated to effect.

The ESETT Anesthetic Trial: Though not yet published as a full trial, retrospective data suggest midazolam achieves seizure control in 60-80% of RSE cases, with faster time to seizure control compared to propofol or pentobarbital due to its ease of rapid titration.[17]

Pearl: Midazolam is the most practical first-line anesthetic for RSE in most ICUs due to its rapid onset, titrability, and familiarity. It doesn't require specialized lipid formulations or cardiac monitoring equipment beyond standard ICU care.

Oyster: Tachyphylaxis develops rapidly (within 24-48 hours), often requiring escalating doses. Metabolic acidosis may occur with high-dose midazolam infusions (>1 mg/kg/hr) due to propylene glycol in the formulation. Monitor anion gap and lactate. Respiratory depression is universal—patients require mechanical ventilation.

Hack: When midazolam doses exceed 0.5-0.6 mg/kg/hr, consider transitioning to propofol or pentobarbital rather than continuing to escalate. Benzodiazepine tolerance limits midazolam's usefulness in SRSE.

Propofol: The Neurocritical Care Standard

Propofol (1-2 mg/kg loading dose, then 30-200 mcg/kg/min continuous infusion) offers multiple advantages: rapid onset and offset, additional neuroprotective effects (cerebral metabolic suppression), and concurrent provision of sedation for mechanical ventilation.[18]

Pearl: Propofol's short half-life allows for rapid neurological assessments when paused, making it ideal for patients in whom frequent neurological exams are needed or when the diagnosis is uncertain.

Oyster: Propofol infusion syndrome (PRIS) is a rare but potentially fatal complication characterized by metabolic acidosis, rhabdomyolysis, cardiac failure, and renal failure. Risk factors include infusion rates >80 mcg/kg/min for >48 hours, young age, critical illness, catecholamine administration, and carbohydrate deficiency.[19] Monitor creatine kinase, triglycerides, and lactate. Mortality from PRIS approaches 30-60%.

Hack: Maintain propofol infusions at <80 mcg/kg/min when possible. If higher doses are required to control seizures, strongly consider transitioning to pentobarbital. Use adjunctive ASMs aggressively to facilitate lower propofol dosing.

Pentobarbital: The Heavy Artillery

Pentobarbital (5-15 mg/kg loading dose at ≤50 mg/min, then 0.5-5 mg/kg/hr) is a barbiturate with potent anticonvulsant effects via GABA-A receptor enhancement and voltage-gated sodium channel blockade.[20] It induces burst-suppression or even electrocerebral silence.

Pearl: Pentobarbital is the most reliable agent for achieving complete seizure control and burst-suppression in SRSE. Consider it when midazolam and propofol have failed, or when patients require deep anesthetic coma for other reasons (e.g., refractory intracranial hypertension).

Oyster: Pentobarbital causes profound hemodynamic instability (hypotension in >50% of patients), often requiring vasopressor support. Its long half-life (15-50 hours) makes neurological assessments difficult and prolongs ICU/ventilator time. Immunosuppression increases nosocomial infection risk. Ileus is common.[21]

Hack: Optimize hemodynamics proactively before loading pentobarbital. Ensure adequate volume resuscitation and have vasopressors ready. Consider pulmonary artery catheter or advanced hemodynamic monitoring in tenuous patients. Accept that neurological exams will be unreliable for days after discontinuation.

Ketamine: The Mechanistically Distinct Option

Ketamine (0.5-3 mg/kg loading dose, then 0.6-10 mg/kg/hr infusion) acts via NMDA receptor antagonism, offering a mechanistically distinct approach when GABAergic agents fail.[22]

Evidence Base: Case series and small studies suggest ketamine terminates SRSE in 50-60% of cases when used as adjunctive or salvage therapy.[23] It may be particularly useful in autoimmune encephalitis and febrile infection-related epilepsy syndrome (FIRES), where glutamatergic mechanisms predominate.

Pearl: Ketamine doesn't cause respiratory depression, making it attractive for patients on minimal respiratory support or when weaning mechanical ventilation is a priority. It preserves hemodynamics better than other anesthetics and may provide neuroprotection via anti-inflammatory effects.

Oyster: Concerns about ketamine exacerbating intracranial hypertension have been largely refuted in modern critical care literature, but avoid in patients with uncontrolled intracranial hypertension until ICP monitoring is in place.[24] Hypersalivation and emergence reactions can occur. High doses may impair EEG interpretation due to rhythmic theta/delta activity.

Hack: Use ketamine as an adjunct to GABAergic anesthetics (e.g., midazolam + ketamine) rather than monotherapy. The combination often allows dose reduction of both agents and may exploit synergistic mechanisms.

Volatile Anesthetics: The Unconventional Rescue

Isoflurane and desflurane have been used as last-resort therapies in SRSE refractory to all IV anesthetics.[25] They require specialized anesthesia equipment (vaporizers) and scavenging systems in the ICU environment.

Evidence: Case reports and small series suggest volatile anesthetics may terminate SRSE in 40-70% of otherwise refractory cases.[26] They offer the advantage of rapid titratability and EEG monitoring capability.

Practical Limitations: Most ICUs lack infrastructure for volatile anesthetics. Environmental contamination, staff exposure concerns, and the need for specialized equipment limit applicability. Reserve for tertiary centers with SRSE expertise and infrastructure.

EEG Targets: How Deep is Deep Enough?

Continuous EEG (cEEG) monitoring is mandatory for RSE/SRSE management, yet optimal EEG targets remain debated.[27]

The Spectrum of Suppression:

Seizure freedom: Abolition of ictal patterns without burst-suppression
Burst-suppression: Alternating periods of EEG activity and suppression, quantified by suppression ratio
Electrocerebral silence: Complete suppression of EEG activity

Current Evidence: The 2012 Neurocritical Care Society guidelines suggested targeting burst-suppression with inter-burst intervals of ≥1 second or electrocerebral silence for 24-48 hours.[28] However, more recent data challenge the necessity of deep suppression.

The STESS Trial Post-Hoc Analysis: Aggressive EEG targets (burst-suppression) were not associated with improved outcomes compared to seizure suppression alone, and deeper suppression correlated with increased complications including hypotension and infections.[29]

Pearl: Current practice is evolving toward less aggressive EEG targets. Aim for seizure freedom without necessarily pursuing burst-suppression unless seizures recur at lighter anesthetic levels. This "minimal effective depth" approach may reduce complications while maintaining seizure control.

Oyster: Don't mistake periodic discharges (GPDs, LPDs) for seizures when titrating anesthetics. While controversial, most experts do not aggressively treat periodic patterns unless they're clearly ictal (e.g., "ictal-interictal continuum" patterns with clear clinical or EEG evolution). Over-treatment of non-ictal patterns leads to unnecessarily deep sedation and complications.

Hack: Use quantitative EEG (qEEG) trends (suppression ratio, asymmetry index, spectral array) to guide anesthetic titration at the bedside. These allow rapid adjustments without waiting for real-time EEG interpretation. Target suppression ratio of 50-80% if pursuing burst-suppression.

The Weaning Protocol: Avoiding Yo-Yo Status

Premature or overly aggressive weaning precipitates seizure recurrence in 30-50% of cases.[30] A structured approach is essential.

Standard Weaning Protocol:

Timing: Maintain anesthetic at therapeutic levels for 24-48 hours after last electrographic seizure
Rate: Reduce dose by 10-20% every 3-6 hours while monitoring cEEG continuously
Optimization: Ensure at least 2-3 non-anesthetic ASMs are at therapeutic levels before weaning
Re-escalation: If seizures recur, return to previous effective dose, add additional ASM, and attempt weaning again after 24-48 hours

Pearl: Load additional long-acting ASMs (e.g., lacosamide, phenobarbital, topiramate) before weaning anesthetics. This "chemical carpet" approach maximizes the chance of successful liberation from anesthetics.

Hack: Consider a "trial of awakening" before full weaning. Briefly pause the anesthetic while maintaining cEEG to assess for seizure recurrence. If seizures emerge immediately, you've identified the need for additional ASM optimization. If not, proceed with gradual weaning. This strategy can save days of ICU time by avoiding doomed wean attempts.

Adjunctive and Rescue Therapies for SRSE

When standard anesthetics fail or cannot be safely continued, multiple adjunctive therapies exist, though evidence is limited to case series and retrospective studies.

Magnesium Sulfate

High-dose magnesium (loading dose 4-6 g IV over 20 minutes, then 2-6 g/hr infusion targeting serum levels of 3.5-5.0 mmol/L) may provide adjunctive benefit via NMDA receptor antagonism.[31] It's particularly considered in eclampsia-related SE and as an adjunct to ketamine.

Hack: Magnesium is essentially free, widely available, and low-risk. When SRSE is not responding, empiric addition of high-dose magnesium is reasonable while awaiting advanced therapies.

Hypothermia

Therapeutic hypothermia (32-34°C) may reduce cerebral metabolic demand and seizure activity.[32] Small case series report seizure termination in 60-70% of hypothermia-treated SRSE patients, though causality is uncertain given concurrent immunotherapy in many cases.

Oyster: Hypothermia causes coagulopathy, cardiac arrhythmias, immunosuppression, and hemodynamic instability. It should be considered only in highly refractory cases at specialized centers.

Immunotherapy

Increasingly recognized as critical for SRSE, particularly in cryptogenic cases. See the section on autoimmune encephalitis below.

Electroconvulsive Therapy (ECT)

Case reports describe successful termination of SRSE with ECT when all other therapies failed.[33] Mechanism may involve GABAergic enhancement or anti-inflammatory effects. Requires anesthesia infrastructure and is typically a last-resort therapy.

Ketogenic Diet

The ketogenic diet induces ketosis (β-hydroxybutyrate 3-6 mmol/L), which may exert anticonvulsant effects via multiple mechanisms including enhanced GABA synthesis and adenosine modulation.[34] Retrospective studies in SRSE report seizure termination in 50-70% of pediatric cases and 30-50% of adult cases.

Practical Implementation: Enteral formulations (ketogenic formula feeds) or parenteral formulations can achieve ketosis within 2-3 days. Target a 4:1 ratio of fats to carbohydrates plus protein.

Hack: The ketogenic diet is most practical in SRSE cases expected to require prolonged ICU management. Start early (within the first week) if initial therapies fail rather than waiting until all else has been exhausted.

Cannabidiol (CBD)

Pharmaceutical-grade CBD (Epidiolex) at doses of 10-20 mg/kg/day has shown promise in treatment-resistant epilepsy.[35] Its role in acute SRSE is undefined, but case reports describe use in desperate situations.

The SRSE Pipeline: When Do We Stop?

SRSE management forces uncomfortable questions about futility. No validated prognostic tools exist, but several factors inform decision-making:

Poor Prognostic Indicators:

Duration >30 days
Age >65 years
Anoxic or infectious etiology
Requirement for three or more anesthetic agents
Malignancy-related SE
Highly malignant EEG background (suppressed or discontinuous)

Better Prognostic Indicators:

Autoimmune etiology (potentially reversible)
Younger age
Preserved EEG background between seizures
Response to immunotherapy

Pearl: Goals-of-care discussions should begin early in SRSE, involve palliative care when appropriate, and be revisited regularly. Explore what meaningful recovery looks like for the patient. Neurological outcomes in SRSE survivors are heterogeneous—some return to baseline, others survive with severe disability.

NCSE (Non-Convulsive Status Epilepticus): Who Needs an Urgent EEG?

The Invisible Epidemic

Non-convulsive status epilepticus (NCSE) is defined as continuous or recurrent seizure activity with altered consciousness but without prominent motor manifestations.[36] It accounts for 25-40% of all SE cases and is notoriously underdiagnosed due to its subtle clinical presentation.

Clinical Presentations: A Spectrum

NCSE encompasses a spectrum from minimally impaired awareness to coma:

Absence SE: Impaired consciousness with confusion, automatisms, and behavioral changes. Typically occurs in patients with known generalized epilepsy.
Complex Partial (Focal Impaired Awareness) SE: Fluctuating confusion, automatisms, and behavioral changes in patients with focal epilepsy history.
Subtle SE: Follows generalized convulsive SE that has been partially treated. Minimal motor activity (eye deviation, nystagmus, subtle facial twitching) with coma. Represents the "burned-out" phase of convulsive SE.
De Novo NCSE in the Elderly: Occurs in elderly patients without epilepsy history, presenting with acute confusion or coma. Often associated with acute illnesses (infections, metabolic derangements, medications).

Who Needs an Urgent EEG? The Clinical Predictors

Given that EEG availability is limited and not every confused ICU patient can undergo continuous monitoring, clinical prediction rules help prioritize.

The Sutter Criteria for NCSE Risk: A retrospective study identified independent predictors of NCSE in altered mental status patients:[37]

Witnessed seizure prior to arrival
Sepsis
Acute brain lesion (stroke, hemorrhage, trauma)
Eye opening to noxious stimuli only
Failure to improve after stopping sedation (in mechanically ventilated patients)

Pearl: Any post-ictal patient whose mental status has not returned to baseline within 30-60 minutes should undergo EEG to exclude NCSE. Similarly, any unexplained fluctuating encephalopathy, particularly in elderly patients or those with acute brain lesions, warrants EEG.

The "2HELPS2B Score": A Practical Tool

Developed and validated for predicting NCSE in critically ill patients with altered mental status:[38]

Criteria (2 points each):

Hospitalized
Epilepsy history
Loss of consciousness at presentation
Prior witnessed seizure
Sepsis

Interpretation:

Score ≥4: High risk for NCSE (sensitivity 97%, specificity 33%)
Score ≥6: Very high risk (sensitivity 85%, specificity 67%)

Oyster: The 2HELPS2B score is highly sensitive but poorly specific. A score <4 makes NCSE very unlikely, but high scores don't confirm NCSE—they identify patients who need EEG.

Hack: In resource-limited settings, prioritize continuous EEG for patients with 2HELPS2B ≥6 or those with witnessed seizures and persistent altered mental status. Use routine EEG for lower-risk patients with unexplained encephalopathy.

EEG Findings in NCSE: More Than Just Seizures

The diagnosis of NCSE requires both clinical (altered consciousness) and EEG criteria. The Salzburg Consensus Criteria provide diagnostic rigor:[39]

Definite NCSE requires:

Epileptiform discharges >2.5 Hz, OR
Epileptiform discharges ≤2.5 Hz PLUS EEG and clinical improvement after IV ASM

Possible NCSE includes:

Various patterns of periodic or rhythmic discharges (GPDs, LPDs, LRDA) in patients with altered consciousness where the ictal nature is uncertain

Pearl: The "ictal-interictal continuum" describes EEG patterns that fall between clearly ictal and clearly interictal. Examples include lateralized periodic discharges (LPDs) with evolving frequency or rhythmic delta activity. These patterns are controversial—some represent seizures, others don't. When in doubt, give a trial of benzodiazepines and observe for clinical and EEG improvement (the "Salzburg approach").

Oyster: Not all rhythmic or periodic EEG activity represents seizures. Generalized periodic discharges (GPDs) in post-anoxic coma are usually not seizures and don't warrant aggressive treatment. Over-treatment of non-ictal EEG patterns is common and exposes patients to unnecessary medication toxicity.

The IV Benzodiazepine Trial: A Diagnostic and Therapeutic Maneuver

When the EEG pattern is ambiguous (ictal-interictal continuum), a trial of IV lorazepam (2-4 mg) or midazolam (2-5 mg) serves dual purposes:[40]

Diagnostic: If both clinical and EEG patterns improve, this supports an ictal diagnosis
Therapeutic: If truly ictal, immediate treatment is provided

Hack: Document mental status quantitatively (using FOUR score or GCS) before and after benzodiazepine administration. Videotape the patient if possible. Clear clinical improvement supports treating the EEG pattern as ictal, even if electrographically ambiguous.

Treatment of NCSE: Is Aggressive Always Better?

The urgency and aggressiveness of NCSE treatment remain debated and depend on the subtype.

Generalized NCSE (absence SE, subtle SE following convulsive SE): Treat aggressively as you would convulsive SE. These subtypes carry risks of neuronal injury and systemic complications.

Focal NCSE without impaired consciousness (e.g., epilepsia partialis continua): Less urgency. Use oral ASMs and avoid unnecessary anesthetics, as the risk-benefit ratio favors less aggressive treatment.

Complex partial SE: Intermediate urgency. Use IV ASMs (benzodiazepines, levetiracetam, fosphenytoin, valproate) but reserve anesthetics for truly refractory cases lasting hours to days.

The STESS Prognostic Score: This validated score predicts mortality in NCSE using age, history of prior seizures, level of consciousness, and EEG pattern.[41] It can help inform treatment intensity and prognosis discussions.

Pearl: De novo absence SE in the elderly often responds dramatically to IV benzodiazepines or valproate. Don't escalate unnecessarily if initial therapy works quickly.

Oyster: Subtle SE after convulsive SE carries high mortality (up to 50%) not necessarily from ongoing seizures but from the underlying etiology (anoxia, hemorrhage). Aggressive seizure treatment may not improve outcomes if the primary insult is irreversible.

The Imitators of Status: Psychogenic Non-Epileptic Seizures (PNES) and Post-Anoxic Myoclonus

Psychogenic Non-Epileptic Seizures (PNES): The Great Masquerader

PNES, also called dissociative seizures or functional seizures, are paroxysmal episodes resembling epileptic seizures but lacking abnormal electrical brain activity.[42] They represent a manifestation of psychological distress, not malingering or voluntary simulation.

Epidemiology: PNES account for 5-20% of patients referred to epilepsy monitoring units and up to 10% of presumed SE cases in some series.[43] Delay in diagnosis averages 7 years, during which patients often receive unnecessary ASMs and ICU admissions.

Clinical Red Flags for PNES

No single feature is pathognomonic, but a constellation of features should raise suspicion:

Semiology:

Prolonged duration (>2 minutes) with waxing and waning intensity
Asynchronous, thrashing movements
Side-to-side head shaking
Pelvic thrusting
Eye closure (epileptic seizures typically cause eye opening)
Crying or screaming during the event
Recall of ictal events
Gradual onset and offset (epileptic seizures are abrupt)

Context:

Multiple emergency department visits for "seizures"
Witnessed seizures only (never occurs when alone)
Unusual triggers (emotional stress, arguments, specific people)
Refractory to multiple ASMs at high doses
Lack of post-ictal confusion or drowsiness

Pearl: The "ictal hand drop test" has reasonable specificity: lift the patient's hand above their face and release it. In epileptic seizures (except frontal lobe), the hand typically falls onto the face. In PNES, the hand often avoids the face. However, this test is neither perfectly sensitive nor specific.[44]

Oyster: PNES and epileptic seizures coexist in 10-30% of patients (mixed events). Don't assume all events are non-epileptic just because some are PNES. Video-EEG monitoring remains the gold standard for diagnosis. Never diagnose PNES based on semiology alone without EEG correlation.

Laboratory and EEG Findings

Serum Prolactin: Elevated prolactin (>2x baseline) drawn 10-20 minutes post-ictally supports epileptic seizures, but this test has significant limitations. Sensitivity is only 60% for generalized tonic-clonic seizures and much lower for focal seizures. Prolactin elevation is absent in simple partial seizures and many complex partial seizures.[45] False positives occur with syncope and baseline prolactin elevations (medications, stress).

Hack: Use prolactin selectively—draw it only if you've witnessed a typical event and need biomarker confirmation. Draw a baseline level hours later or document a normal historical value. A truly elevated post-ictal prolactin supports epileptic seizures, but a normal value doesn't exclude them.

EEG in PNES: By definition, PNES show no ictal epileptiform activity during events. However, interictal EEG may show epileptiform discharges if the patient also has epilepsy. Video-EEG monitoring capturing typical events while demonstrating lack of ictal activity is diagnostic.

Pearl: When PNES is suspected in the ICU, request video recording of events if continuous video-EEG isn't available. Smartphone videos can provide valuable information for neurologists reviewing the case.

The Diagnostic Conversation: Breaking the News

Delivering a PNES diagnosis requires skill, empathy, and avoidance of stigmatizing language. Poor communication can worsen outcomes and damage the therapeutic alliance.

Framework for Discussion:

Validate the patient's experience: "The events you're having are real and distressing."
Explain positively: "The good news is these aren't epileptic seizures, which means your brain's electrical activity is normal."
Use acceptable terminology: "Dissociative seizures" or "functional seizures" rather than "psychogenic" or "pseudo-seizures"
Provide mechanism: "Your nervous system is producing these events as a response to stress, trauma, or other factors we'll explore."
Emphasize treatability: "These events can improve significantly with the right therapy."
Make referrals: Neuropsychiatry, psychology, or psychiatry with PNES expertise

Oyster: Never accuse patients of "faking" or suggest they can control the events voluntarily. PNES is an involuntary manifestation of psychological distress, not malingering. Such accusations worsen outcomes and may precipitate litigation.

Hack: Involve a neurologist or psychiatrist experienced in functional neurological disorders when delivering the diagnosis. These specialists can provide longitudinal care and evidence-based treatments (cognitive behavioral therapy, acceptance and commitment therapy) that improve outcomes.[46]

Management of Presumed PNES in the ICU

When PNES is strongly suspected but not yet confirmed with video-EEG:

Minimize iatrogenic harm: Avoid unnecessary escalation of ASMs or intubation for "refractory seizures"
Pursue EEG confirmation: Transfer to monitored unit or arrange video-EEG
Avoid benzodiazepines: These can reinforce the episodes if the patient associates them with event termination
Provide reassurance: During events, stay calm, ensure safety, and provide gentle verbal reassurance
Document carefully: Detailed phenomenology helps neurologists differentiate PNES from epileptic seizures

Pearl: If the patient is already intubated for "status epilepticus" and PNES is confirmed, plan for rapid extubation. Prolonged intubation and ICU stays worsen functional neurological disorders through iatrogenic harm and loss of agency.

Post-Anoxic Myoclonus: Lance-Adams Syndrome and Acute Myoclonic Status

Myoclonus following cardiac arrest represents a diagnostic and prognostic challenge. Two distinct entities exist:

Acute Post-Anoxic Myoclonus (Within 24-48 Hours)

Generalized, multifocal myoclonus occurring early after cardiac arrest was historically considered a harbinger of poor prognosis. However, modern data require nuanced interpretation.

Prognostic Significance: In the pre-targeted temperature management (TTM) era, early myoclonus predicted poor outcome with near certainty. However, studies post-TTM show that myoclonus alone (without other poor prognostic features) does not uniformly predict poor outcome.[47] Up to 10-15% of patients with myoclonus may achieve good neurological recovery, particularly if:

Myoclonus is stimulus-induced rather than spontaneous
EEG background is not severely suppressed or burst-suppressed
Somatosensory evoked potentials (SSEPs) show preserved N20 responses bilaterally
Neuroimaging shows no extensive anoxic injury

EEG Findings: Acute post-anoxic myoclonus may occur with various EEG patterns:

Generalized periodic discharges (GPDs) time-locked to myoclonic jerks ("myoclonic status epilepticus")
Burst-suppression pattern
Suppressed background without epileptiform activity
Electrodecremental response to muscle jerks (not epileptiform)

The Controversy: Is acute post-anoxic myoclonus "epileptic"? This remains debated. Some patterns clearly represent cortical myoclonus with epileptiform correlates (myoclonic status epilepticus), while others represent subcortical or reticular reflex myoclonus without cortical epileptiform activity.[48]

Treatment Approach:

Benzodiazepines: First-line for symptomatic control (lorazepam or clonazepam)
Levetiracetam: Often added empirically, though evidence is limited
Valproate: May be beneficial for cortical myoclonus
Propofol: For severe, distressing myoclonus impeding care or mechanical ventilation

Pearl: Focus on neuroprognostication using multimodal criteria (EEG background, SSEPs, imaging, clinical examination off sedation) rather than treating myoclonus aggressively for prognostic reasons. If other prognostic indicators suggest potential for good recovery, treat myoclonus supportively while allowing time for neurological recovery.

Oyster: Don't mistake acute post-anoxic myoclonus for seizures requiring aggressive therapy with anesthetics. While some patterns may be epileptic, escalating to midazolam or propofol infusions for isolated myoclonus (without other seizure activity) exposes patients to unnecessary sedation that impairs prognostic assessment.

Hack: Use neuromuscular blockade temporarily to facilitate mechanical ventilation or procedures if myoclonus is mechanically problematic, rather than escalating sedation unnecessarily. This allows ongoing EEG monitoring without confounding movements.

Lance-Adams Syndrome: Chronic Post-Anoxic Action Myoclonus

Lance-Adams syndrome (LAS) represents chronic, action-induced myoclonus following successful resuscitation from anoxic injury.[49] Unlike acute post-anoxic myoclonus, LAS occurrence confirms good cortical recovery—patients are awake and interactive but experience disabling myoclonic jerks triggered by voluntary movement or intention.

Clinical Features:

Appears days to weeks after emergence from coma
Action-induced myoclonus (worse with voluntary movement, goal-directed tasks)
Preserved consciousness and cognition
May include stimulus-sensitive components (sound, touch)
Disabling impact on activities of daily living

Pathophysiology: LAS results from cerebellar and brainstem (inferior olive) injury causing abnormal oscillations in cerebello-thalamo-cortical circuits. It represents post-hypoxic cerebellar ataxia with myoclonus.

Treatment:

Levetiracetam: First-line, often effective at doses of 2000-4000 mg/day
Valproate: Particularly effective for cortical myoclonus component
Clonazepam: Helpful for action myoclonus but causes sedation
Piracetam: Not available in the U.S. but used in Europe with good effect
Zonisamide: Emerging evidence for myoclonus syndromes
5-Hydroxytryptophan (5-HTP): May augment other therapies

Combination therapy is typically necessary, and complete suppression is rare. The goal is functional improvement rather than complete abolition of myoclonus.

Pearl: Lance-Adams syndrome, while disabling, is compatible with meaningful recovery and good quality of life. Early aggressive rehabilitation, occupational therapy, and realistic goal-setting improve outcomes. Some patients achieve near-complete functional independence despite persistent myoclonus.

Oyster: Don't give up on patients with LAS. While literature emphasizes the syndrome's severity, modern case series show that 40-60% of patients achieve functional independence with aggressive symptomatic treatment and rehabilitation.[50]

Autoimmune Encephalitis as a Cause of New-Onset Refractory Status Epilepticus

The Paradigm Shift: NORSE and FIRES

New-Onset Refractory Status Epilepticus (NORSE) is defined as RSE in a patient without active epilepsy or other clear acute or active structural, toxic, or metabolic cause, with a new onset of refractory seizures.[51] When NORSE occurs in the context of a febrile illness, it's termed Febrile Infection-Related Epilepsy Syndrome (FIRES).

The recognition that autoimmune encephalitis underlies many NORSE cases has revolutionized management, emphasizing the role of immunotherapy in SRSE.

Epidemiology and Etiology

NORSE accounts for approximately 10-15% of RSE cases.[52] In roughly 50% of NORSE cases, no etiology is identified despite extensive workup ("cryptogenic NORSE"). However, autoimmune encephalitis is identified in 20-30% of cases, with the following antibodies most commonly implicated:

Anti-NMDA receptor (NMDAR) encephalitis (most common)
Anti-LGI1 (leucine-rich glioma-inactivated 1) encephalitis
Anti-CASPR2 encephalitis
Anti-GABA-A receptor encephalitis
Anti-GABA-B receptor encephalitis
Anti-AMPA receptor encephalitis

Other causes of NORSE include:

Paraneoplastic syndromes (anti-Hu, anti-Ma2)
CNS infections (HSV encephalitis, despite negative initial testing)
Autoimmune disorders (lupus cerebritis, Hashimoto's encephalopathy)
Mitochondrial disease
Cryptogenic/idiopathic

Clinical Red Flags for Autoimmune Etiology

Suggestive Features:

New-onset seizures in previously healthy adolescent or young adult
Psychiatric prodrome: Anxiety, psychosis, behavioral changes, hallucinations preceding seizures (particularly NMDAR encephalitis)
Cognitive decline: Prominent memory impairment, confusion
Movement disorders: Orofacial dyskinesias, choreoathetosis, dystonia, rigidity (NMDAR encephalitis)
Autonomic instability: Tachycardia, labile blood pressure, hyperthermia, hypoventilation
Hyponatremia: Particularly with LGI1 encephalitis (SIADH in 60% of cases)
Faciobrachial dystonic seizures: Pathognomonic for LGI1 encephalitis—brief (seconds), frequent (up to hundreds/day) episodes of dystonic posturing of face and arm

Oyster: Anti-NMDAR encephalitis can present with isolated SE in 20-30% of cases without the full clinical tetrad (psychiatric symptoms, seizures, movement disorder, autonomic instability). Maintain high suspicion in young patients with cryptogenic NORSE.[53]

Diagnostic Workup for Autoimmune Encephalitis

When autoimmune etiology is suspected, perform comprehensive antibody testing on both serum and CSF:

Antibody Panel:

NMDAR, LGI1, CASPR2, GABA-A, GABA-B, AMPA receptors (CSF more sensitive than serum)
Paraneoplastic antibodies (Hu, Ma2, CV2/CRMP5, amphiphysin, Yo)
Voltage-gated potassium channel (VGKC) complex antibodies (includes LGI1 and CASPR2)

Supportive Testing:

CSF analysis: Mild lymphocytic pleocytosis (50-60% of cases), elevated protein, oligoclonal bands, normal glucose
MRI brain:
- NMDAR: Often normal, or may show T2/FLAIR hyperintensities in cortex, hippocampus, or basal ganglia
- LGI1: Mesial temporal T2/FLAIR hyperintensities (70% of cases)
- GAD65: Mesial temporal sclerosis
EEG: Non-specific; may show temporal lobe seizures, diffuse slowing, or "extreme delta brush" (specific for NMDAR encephalitis—rhythmic delta with superimposed beta, seen in 30% of severe cases)[54]
Tumor screening: Pelvic ultrasound or CT (NMDAR—ovarian teratoma in 50% of women), chest/abdomen/pelvis CT (paraneoplastic syndromes), testicular ultrasound (NMDAR—testicular teratoma rare but described)

Pearl: Antibody testing can take 1-2 weeks. Don't wait for results before initiating empiric immunotherapy in patients with strong clinical suspicion for autoimmune encephalitis. Early treatment improves outcomes.

Hack: Send antibody testing to reference laboratories (Mayo Clinic, Oxford Autoimmune Neurology Diagnostic Laboratory, Euroimmun) rather than commercial labs. Sensitivity and specificity vary significantly between laboratories, and false negatives are common with some assays.[55]

Immunotherapy: The Cornerstone of Treatment

When autoimmune encephalitis is suspected or confirmed, immunotherapy should be initiated urgently, in parallel with ASM optimization.

First-Line Immunotherapy

High-Dose Corticosteroids:

Methylprednisolone 1 gram IV daily × 5 days
Follow with oral prednisone 1 mg/kg/day with slow taper over months

Intravenous Immunoglobulin (IVIG):

2 g/kg divided over 2-5 days (typically 0.4 g/kg/day × 5 days)
Repeat monthly if initial response

Plasma Exchange (PLEX):

5-7 exchanges over 10-14 days
Removes circulating antibodies more rapidly than IVIG

Combination vs. Sequential Therapy: Expert consensus favors combining steroids with either IVIG or PLEX as first-line therapy.[56] Some data suggest PLEX may be superior to IVIG for severe cases, though head-to-head trials are lacking.

Pearl: Response to first-line immunotherapy may take 4-8 weeks. Don't declare immunotherapy "failed" after only days. However, if no improvement occurs after 2-3 weeks of first-line therapy, escalate to second-line agents.

Second-Line Immunotherapy

Reserved for patients not responding to first-line therapy after 2-4 weeks:

Rituximab:

Anti-CD20 monoclonal antibody depleting B cells
Dose: 375 mg/m² IV weekly × 4 weeks, or 1000 mg IV on days 1 and 15
Particularly effective for NMDAR encephalitis (antibody-mediated, B-cell dependent)

Cyclophosphamide:

Alkylating agent with broad immunosuppression
Dose: 750 mg/m² IV monthly × 6 months
More toxic than rituximab but may be effective when rituximab fails

Tocilizumab:

IL-6 receptor antagonist
Emerging therapy for refractory cases[57]
Dose: 8 mg/kg IV every 4 weeks

Bortezomib:

Proteasome inhibitor targeting plasma cells
Reported in case series for refractory NMDAR encephalitis[58]

Pearl: Early escalation to second-line therapy (within 4 weeks) improves outcomes in NMDAR encephalitis. Don't wait months before adding rituximab or cyclophosphamide if first-line therapies are ineffective.

Oyster: Immunotherapy carries risks: infection (particularly with cyclophosphamide and rituximab), infusion reactions, hypogammaglobulinemia, and malignancy (long-term cyclophosphamide). Monitor immunoglobulin levels, provide prophylaxis against opportunistic infections (trimethoprim-sulfamethoxazole, antifungals for prolonged neutropenia), and screen for infections aggressively.

Tumor Screening and Removal

Paraneoplastic autoimmune encephalitis requires tumor identification and removal for optimal outcomes:

NMDAR encephalitis: Ovarian teratoma in 50% of women (higher in those >18 years), testicular teratoma rare in men. Perform pelvic imaging in all women; consider repeat imaging if initial negative but high suspicion.
LGI1 encephalitis: Rarely paraneoplastic (2-10% of cases); screen with chest/abdomen/pelvis CT
GABA-B receptor encephalitis: Small-cell lung cancer in 50-60% of cases
AMPA receptor encephalitis: Thymoma, lung, breast, or ovarian cancers in 70% of cases

Hack: If pelvic ultrasound is negative in a woman with NMDAR encephalitis, obtain pelvic MRI—teratomas can be small and missed on ultrasound. Consider laparoscopic ovarian exploration if MRI is negative but suspicion remains very high.

Prognosis and Long-Term Outcomes

NMDAR Encephalitis:

80% achieve good recovery (modified Rankin Scale 0-2) within 2 years with appropriate treatment
Median time to recovery: 6-12 months
Relapses occur in 10-20% (higher if tumor not removed or inadequate immunotherapy)
Mortality: 5-7% with treatment

LGI1 Encephalitis:

Generally good prognosis with early treatment
Cognitive sequelae (memory impairment) common despite seizure control
Mortality: 2-5%

Cryptogenic NORSE/FIRES:

Poorer prognosis than antibody-positive cases
Mortality: 20-30%
Severe cognitive and neurological sequelae common in survivors
Many develop drug-resistant epilepsy

Pearl: Long-term epilepsy develops in 10-30% of autoimmune encephalitis survivors, even after successful immunotherapy. Maintain ASMs during recovery and attempt slow weaning only after 6-12 months seizure-free with normalized EEG.

The Ketogenic Diet in FIRES

For pediatric FIRES cases, early initiation of the ketogenic diet (within the first week) has shown promise, with seizure control reported in 50-70% of cases in retrospective series.[59] The diet may exert anti-inflammatory effects in addition to metabolic anticonvulsant actions.

Practical Consideration: The ketogenic diet complements immunotherapy and should be considered early in FIRES rather than as a last resort.

Putting It All Together: The ICU Approach to Uncontrolled Seizures

The Time-Based Algorithm

Time 0-5 minutes:

Secure airway if needed (GCS <8, aspiration risk)
Obtain IV access (two large-bore IVs)
Check glucose, give thiamine 100 mg IV if alcoholism or malnutrition suspected
First-line: Lorazepam 0.1 mg/kg IV (or diazepam 0.15-0.2 mg/kg IV, or midazolam 10 mg IM if no IV access)

Time 5-25 minutes (Second-line therapy):

If seizures persist >5 minutes after benzodiazepine, initiate second-line agent:
- Levetiracetam 60 mg/kg IV (max 4500 mg) over 10 minutes
- OR Fosphenytoin 20 PE/kg IV at 150 PE/min
- OR Valproate 40 mg/kg IV (max 3000 mg) at 6-10 mg/kg/min
Consider lacosamide 200-400 mg IV if above agents fail or contraindicated

Time 25-60 minutes (Assess for RSE):

If seizures continue despite adequate second-line therapy, RSE is declared
Initiate continuous EEG monitoring
Consider third-line ASM (different mechanism from second-line)
Prepare for ICU transfer and intubation

Time >60 minutes (Anesthetic therapy for RSE):

Intubation and mechanical ventilation
Continuous EEG monitoring (cEEG)
Initiate anesthetic: midazolam 0.2 mg/kg load, then 0.1-0.2 mg/kg/hr infusion
Alternative: propofol 1-2 mg/kg load, then 30-80 mcg/kg/min
Target: Seizure cessation (burst-suppression optional, not mandatory)
Load additional ASMs: Consider adding lacosamide, phenobarbital, topiramate, or others
Pursue etiological workup urgently

The Diagnostic Workup Checklist

Immediate Labs:

Complete blood count, comprehensive metabolic panel
Magnesium, calcium, phosphate
Antiepileptic drug levels (if patient on ASMs chronically)
Toxicology screen (urine and serum)
Blood cultures if febrile
Ammonia, lactate
Pregnancy test (women of childbearing age)

Neuroimaging:

CT head (immediately to exclude hemorrhage, mass, stroke)
MRI brain with and without contrast (when stabilized; superior for subtle lesions, encephalitis, posterior circulation stroke)

CSF Analysis (Lumbar Puncture):

Perform once coagulopathy corrected and no contraindications
Cell count with differential, glucose, protein
Gram stain, culture, HSV PCR, VZV PCR
Hold CSF for autoimmune/paraneoplastic antibody testing if indicated
Consider sending for tuberculosis, fungal studies based on risk factors

EEG:

Routine EEG if seizures terminated (assess for NCSE, epileptiform activity)
Continuous EEG for RSE/SRSE and any patient with unexplained altered mental status

Autoimmune Workup (if indicated):

Serum and CSF antibodies (NMDAR, LGI1, CASPR2, GABA-A/B, paraneoplastic panel)
Tumor screening (chest/abdomen/pelvis CT, pelvic ultrasound/MRI in women)
Thyroid function, anti-thyroid antibodies (Hashimoto's encephalopathy)

Clinical Pearls: The Top 10 for the Intensivist

Time is brain in SE: Every minute counts. Don't deliberate endlessly about the "perfect" drug—give an appropriate second-line agent quickly.
Recognize NCSE: If mental status hasn't returned to baseline 30-60 minutes post-ictally, get an EEG.
Less is often more in anesthetic targets: Seizure cessation without burst-suppression may be safer than aggressive deep suppression. Individualize targets.
Think autoimmune in young, previously healthy patients: NORSE should prompt urgent immunotherapy consideration, even before antibody confirmation.
PNES is common: Not every rhythmic movement is a seizure. Know the red flags and pursue video-EEG confirmation before escalating therapy.
Post-anoxic myoclonus isn't always futile: Multimodal prognostication, not myoclonus alone, should guide decisions.
Load multiple ASMs before weaning anesthetics: Create a "chemical carpet" to maximize the chance of successful liberation from continuous infusions.
Monitor for complications: SE and its treatment cause rhabdomyolysis, aspiration pneumonia, pulmonary edema, cardiac arrhythmias, acidosis, electrolyte derangements, and thromboembolism. Prevent and treat proactively.
Involve neurology early: Complex SE cases benefit from specialist input regarding ASM selection, immunotherapy, and prognostication.
Have the goals-of-care conversation: SRSE forces difficult decisions. Early, honest communication with families about prognosis and potential outcomes is essential.

Conclusion

Status epilepticus and its mimics represent some of the most complex and time-sensitive challenges in critical care medicine. Success requires rapid recognition, systematic treatment escalation, continuous EEG monitoring, and thoughtful consideration of etiology—particularly autoimmune causes in refractory cases. While benzodiazepines remain the cornerstone of initial therapy, modern evidence supports flexibility in second-line agent selection based on patient-specific factors rather than rigid protocols. For refractory and super-refractory SE, a balanced approach to anesthetic depth, aggressive pursuit of underlying causes, and judicious use of immunotherapy when appropriate can improve outcomes. Equally important is the recognition that not all movements are seizures: familiarity with PNES, post-anoxic myoclonus, and other mimics prevents iatrogenic harm from over-treatment. As the field evolves, intensivists must stay current with emerging therapies, refine prognostic capabilities, and maintain a compassionate approach to decision-making in these often devastating cases.

References

Trinka E, Cock H, Hesdorffer D, et al. A definition and classification of status epilepticus—Report of the ILAE Task Force on Classification of Status Epilepticus. Epilepsia. 2015;56(10):1515-1523.
Lowenstein DH, Alldredge BK. Status epilepticus. N Engl J Med. 1998;338(14):970-976.
Betjemann JP, Lowenstein DH. Status epilepticus in adults. Lancet Neurol. 2015;14(6):615-624.
Shorvon S, Ferlisi M. The treatment of super-refractory status epilepticus: a critical review of available therapies and a clinical treatment protocol. Brain. 2011;134(10):2802-2818.
Kapur J, Elm J, Chamberlain JM, et al. Randomized trial of three anticonvulsant medications for status epilepticus. N Engl J Med. 2019;381(22):2103-2113.
Cock HR, Schapira AH. A comparison of lorazepam and diazepam as initial therapy in convulsive status epilepticus. QJM. 2002;95(4):225-231.
Fischer JH, Patel TV, Fischer PA. Fosphenytoin: clinical pharmacokinetics and comparative advantages in the acute treatment of seizures. Clin Pharmacokinet. 2003;42(1):33-58.
Gerstner T, Büsing D, Bell N, et al. Valproic acid-induced pancreatitis: 16 new cases and a review of the literature. J Gastroenterol. 2007;42(1):39-48.
Yasiry Z, Shorvon SD. The relative effectiveness of five antiepileptic drugs in treatment of benzodiazepine-resistant convulsive status epilepticus: a meta-analysis of published studies. Seizure. 2014;23(3):167-174.
Chamberlain JM, Kapur J, Shinnar S, et al. Efficacy of levetiracetam, fosphenytoin, and valproate for established status epilepticus by age group (ESETT): a double-blind, responsive-adaptive, randomised controlled trial. Lancet. 2020;395(10231):1217-1224.
Kellinghaus C. Lacosamide as treatment for partial epilepsy: mechanisms of action, pharmacology, effects, and safety. Ther Clin Risk Manag. 2009;5:757-766.
Hofler J, Trinka E. Lacosamide as a new treatment option in status epilepticus. Epilepsia. 2013;54(3):393-404.
Novy J, Rossetti AO. Oral lacosamide as an add-on therapy in refractory epilepsy and status epilepticus. Epilepsy Behav. 2014;37:137-140.
Brophy GM, Bell R, Claassen J, et al. Guidelines for the evaluation and management of status epilepticus. Neurocrit Care. 2012;17(1):3-23.
Rossetti AO, Lowenstein DH. Management of refractory status epilepticus in adults: still more questions than answers. Lancet Neurol. 2011;10(10):922-930.
Silbergleit R, Durkalski V, Lowenstein D, et al. Intramuscular versus intravenous therapy for prehospital status epilepticus. N Engl J Med. 2012;366(7):591-600.
Fernandez A, Claassen J. Refractory status epilepticus. Curr Opin Crit Care. 2012;18(2):127-131.
Rossetti AO, Reichhart MD, Schaller MD, et al. Propofol treatment of refractory status epilepticus: a study of 31 episodes. Epilepsia. 2004;45(7):757-763.
Kam PC, Cardone D. Propofol infusion syndrome. Anaesthesia. 2007;62(7):690-701.
Claassen J, Hirsch LJ, Emerson RG, Mayer SA. Treatment of refractory status epilepticus with pentobarbital, propofol, or midazolam: a systematic review. Epilepsia. 2002;43(2):146-153.
Iyer VN, Hoel R, Rabinstein AA. Propofol infusion syndrome in patients with refractory status epilepticus: an 11-year clinical experience. Crit Care Med. 2009;37(12):3024-3030.
Synowiec AS, Singh DS, Yenugadhati V, et al. Ketamine use in the treatment of refractory status epilepticus. Epilepsy Res. 2013;105(1-2):183-188.
Gaspard N, Foreman B, Judd LM, et al. Intravenous ketamine for the treatment of refractory status epilepticus: a retrospective multicenter study. Epilepsia. 2013;54(8):1498-1503.
Zeiler FA, Teitelbaum J, West M, Gillman LM. The ketamine effect on intracranial pressure in nontraumatic neurological illness. J Crit Care. 2014;29(6):1096-1106.
Mirsattari SM, Sharpe MD, Young GB. Treatment of refractory status epilepticus with inhalational anesthetic agents isoflurane and desflurane. Arch Neurol. 2004;61(8):1254-1259.
Kramer AH. Early ketamine to treat refractory status epilepticus. Neurocrit Care. 2012;16(2):299-305.
Herman ST, Abend NS, Bleck TP, et al. Consensus statement on continuous EEG in critically ill adults and children, part I: indications. J Clin Neurophysiol. 2015;32(2):87-95.
Brophy GM, Bell R, Claassen J, et al. Guidelines for the evaluation and management of status epilepticus. Neurocrit Care. 2012;17(1):3-23.
Rossetti AO, Logroscino G, Milligan TA, et al. Status Epilepticus Severity Score (STESS): a tool to orient early treatment strategy. J Neurol. 2008;255(10):1561-1566.
Hocker SE, Britton JW, Mandrekar JN, et al. Predictors of outcome in refractory status epilepticus. JAMA Neurol. 2013;70(1):72-77.
Visser NA, Braun KP, Leijten FS, et al. Magnesium treatment for patients with refractory status epilepticus due to POLG1-mutations. J Neurol. 2011;258(2):218-222.
Corry JJ, Dhar R, Murphy T, Diringer MN. Hypothermia for refractory status epilepticus. Neurocrit Care. 2008;9(2):189-197.
Lambrecq V, Villegier AS, Marchal C, et al. Refractory status epilepticus: electroconvulsive therapy as a possible therapeutic strategy. Seizure. 2012;21(9):661-664.
Thakur KT, Probasco JC, Hocker SE, et al. Ketogenic diet for adults in super-refractory status epilepticus. Neurology. 2014;82(8):665-670.
Devinsky O, Cross JH, Laux L, et al. Trial of cannabidiol for drug-resistant seizures in the Dravet syndrome. N Engl J Med. 2017;376(21):2011-2020.
Walker M, Cross H, Smith S, et al. Nonconvulsive status epilepticus: Epilepsy Research Foundation workshop reports. Epileptic Disord. 2005;7(3):253-296.
Sutter R, Kaplan PW, Ruegg S. Independent external validation of the status epilepticus severity score. Crit Care Med. 2013;41(12):e475-479.
Sutter R, Stevens RD, Kaplan PW. Clinical and imaging correlates of EEG patterns in hospitalized patients with encephalopathy. J Neurol. 2013;260(4):1087-1098.
Leitinger M, Beniczky S, Rohracher A, et al. Salzburg Consensus Criteria for Non-Convulsive Status Epilepticus—approach to clinical application. Epilepsy Behav. 2015;49:158-163.
Kaplan PW. The EEG in metabolic encephalopathy and coma. J Clin Neurophysiol. 2004;21(5):307-318.
Rossetti AO, Logroscino G, Milligan TA, et al. Status Epilepticus Severity Score (STESS): a tool to orient early treatment strategy. J Neurol. 2008;255(10):1561-1566.
Reuber M, Fernández G, Bauer J, et al. Diagnostic delay in psychogenic nonepileptic seizures. Neurology. 2002;58(3):493-495.
Duncan R, Razvi S, Mulhern S. Newly presenting psychogenic nonepileptic seizures: incidence, population characteristics, and early outcome from a prospective audit of a first seizure clinic. Epilepsy Behav. 2011;20(2):308-311.
Avbersek A, Sisodiya S. Does the primary literature provide support for clinical signs used to distinguish psychogenic nonepileptic seizures from epileptic seizures? J Neurol Neurosurg Psychiatry. 2010;81(7):719-725.
Chen DK, So YT, Fisher RS. Use of serum prolactin in diagnosing epileptic seizures: report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology. 2005;65(5):668-675.
Goldstein LH, Robinson EJ, Mellers JDC, et al. Cognitive behavioural therapy for adults with dissociative seizures (CODES): a pragmatic, multicentre, randomised controlled trial. Lancet Psychiatry. 2020;7(6):491-505.
Wijdicks EF, Hijdra A, Young GB, et al. Practice parameter: prediction of outcome in comatose survivors after cardiopulmonary resuscitation (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology. 2006;67(2):203-210.
Rossetti AO, Oddo M, Logroscino G, Kaplan PW. Prognostication after cardiac arrest and hypothermia: a prospective study. Ann Neurol. 2010;67(3):301-307.
Lance JW, Adams RD. The syndrome of intention or action myoclonus as a sequel to hypoxic encephalopathy. Brain. 1963;86:111-136.
Werhahn KJ, Brown P, Thompson PD, Marsden CD. The clinical features and prognosis of chronic posthypoxic myoclonus. Mov Disord. 1997;12(2):216-220.
Gaspard N, Foreman BP, Alvarez V, et al. New-onset refractory status epilepticus: etiology, clinical features, and outcome. Neurology. 2015;85(18):1604-1613.
Khawaja AM, DeWolfe JL, Miller DW, Szaflarski JP. New-onset refractory status epilepticus (NORSE)—the potential role for immunotherapy. Epilepsy Behav. 2015;47:17-23.
Dalmau J, Gleichman AJ, Hughes EG, et al. Anti-NMDA-receptor encephalitis: case series and analysis of the effects of antibodies. Lancet Neurol. 2008;7(12):1091-1098.
Schmitt SE, Pargeon K, Frechette ES, et al. Extreme delta brush: a unique EEG pattern in adults with anti-NMDA receptor encephalitis. Neurology. 2012;79(11):1094-1100.
Graus F, Titulaer MJ, Balu R, et al. A clinical approach to diagnosis of autoimmune encephalitis. Lancet Neurol. 2016;15(4):391-404.
Titulaer MJ, McCracken L, Gabilondo I, et al. Treatment and prognostic factors for long-term outcome in patients with anti-NMDA receptor encephalitis: an observational cohort study. Lancet Neurol. 2013;12(2):157-165.
Lee WJ, Lee ST, Byun JI, et al. Rituximab treatment for autoimmune limbic encephalitis in an institutional cohort. Neurology. 2016;86(18):1683-1691.
Scheibe F, Prüss H, Mengel AM, et al. Bortezomib for treatment of therapy-refractory anti-NMDA receptor encephalitis. Neurology. 2017;88(4):366-370.
Nabbout R, Mazzuca M, Hubert P, et al. Efficacy of ketogenic diet in severe refractory status epilepticus initiating fever induced refractory epileptic encephalopathy in school age children (FIRES). Epilepsia. 2010;51(10):2033-2037.
Holtkamp M, Othman J, Buchheim K, Meierkord H. Predictors and prognosis of refractory status epilepticus treated in a neurological intensive care unit. J Neurol Neurosurg Psychiatry. 2005;76(4):534-539.
Treiman DM, Meyers PD, Walton NY, et al. A comparison of four treatments for generalized convulsive status epilepticus. N Engl J Med. 1998;339(12):792-798.
Shorvon S, Baulac M, Cross H, et al. The drug treatment of status epilepticus in Europe: consensus document from a workshop at the first London Colloquium on Status Epilepticus. Epilepsia. 2008;49(7):1277-1285.
Mayer SA, Claassen J, Lokin J, et al. Refractory status epilepticus: frequency, risk factors, and impact on outcome. Arch Neurol. 2002;59(2):205-210.
Rosenow F, Hamer HM, Knake S. The epidemiology of convulsive and nonconvulsive status epilepticus. Epilepsia. 2007;48 Suppl 8:82-84.
DeLorenzo RJ, Waterhouse EJ, Towne AR, et al. Persistent nonconvulsive status epilepticus after the control of convulsive status epilepticus. Epilepsia. 1998;39(8):833-840.
Towne AR, Waterhouse EJ, Boggs JG, et al. Prevalence of nonconvulsive status epilepticus in comatose patients. Neurology. 2000;54(2):340-345.
Laccheo I, Sonmezturk H, Bhatt AB, et al. Non-convulsive status epilepticus and non-convulsive seizures in neurological ICU patients. Neurocrit Care. 2015;22(2):202-211.
Sutter R, Kaplan PW. Electroencephalographic criteria for nonconvulsive status epilepticus: synopsis and comprehensive survey. Epilepsia. 2012;53 Suppl 3:1-51.
Chong DJ, Hirsch LJ. Which EEG patterns warrant treatment in the critically ill? Reviewing the evidence for treatment of periodic epileptiform discharges and related patterns. J Clin Neurophysiol. 2005;22(2):79-91.
Sánchez Fernández I, Abend NS, Agadi S, et al. Time from convulsive status epilepticus onset to anticonvulsant administration in children. Neurology. 2015;84(23):2304-2311.

Key Clinical Pearls Summary Box

Assessment Pearls

✓ 5-minute rule: Treat any seizure lasting >5 minutes as SE—don't wait for the traditional 30-minute definition ✓ NCSE screening: Unexplained altered mental status + any seizure history = urgent EEG needed ✓ 2HELPS2B ≥4: High sensitivity for NCSE risk; prioritize EEG in these patients ✓ Young + healthy + NORSE: Think autoimmune—send antibodies and start immunotherapy empirically

Treatment Pearls

✓ Second-line equipoise: Levetiracetam, fosphenytoin, and valproate are equally effective—choose based on comorbidities, not habit ✓ Midazolam first: Most practical first-line anesthetic for RSE due to ease of titration and safety profile ✓ Less may be more: Seizure freedom without burst-suppression may be safer than aggressive EEG targets ✓ Chemical carpet: Load 2-3 non-anesthetic ASMs before weaning anesthetics to prevent seizure recurrence ✓ Immunotherapy early: Don't wait for antibody confirmation in suspected autoimmune encephalitis—treat within days, not weeks

Diagnostic Pearls

✓ Eye closure during "seizure": Strong clue for PNES, not epileptic seizures ✓ Extreme delta brush on EEG: Pathognomonic for anti-NMDAR encephalitis ✓ Faciobrachial dystonic seizures: Diagnostic for anti-LGI1 encephalitis ✓ Post-anoxic myoclonus ≠ futility: Multimodal prognostication, not myoclonus alone, predicts outcome ✓ Prolactin elevation: Helpful if present, but normal prolactin doesn't exclude epileptic seizures

Safety Pearls

✓ PRIS risk: Keep propofol <80 mcg/kg/min and monitor creatine kinase, triglycerides ✓ Valproate contraindications: Avoid in hepatic failure, pregnancy, and suspected mitochondrial disease ✓ Fosphenytoin cardiac risk: Monitor for hypotension and arrhythmias during infusion ✓ Benzodiazepine tolerance: If midazolam >0.5 mg/kg/hr, transition to alternative anesthetic ✓ Immunotherapy infections: Prophylax against opportunistic infections with rituximab/cyclophosphamide

Oyster (Pitfalls) Summary Box

Diagnostic Oysters

⚠ Mixed seizures: 10-30% of PNES patients also have epileptic seizures—don't assume all events are non-epileptic ⚠ False reassurance: Normal routine EEG doesn't exclude NCSE—may need continuous monitoring ⚠ Antibody-negative AE: 30-50% of autoimmune encephalitis cases are seronegative—don't withhold immunotherapy based on negative tests alone ⚠ Delayed antibody results: Commercial labs have poor sensitivity—send to reference laboratories ⚠ Over-interpreting GPDs: Generalized periodic discharges post-arrest are often not seizures—avoid over-treatment

Treatment Oysters

⚠ Levetiracetam efficacy: May be less effective in children and after prehospital benzodiazepines (ESETT post-hoc) ⚠ Propofol infusion syndrome: Rare but fatal—monitor for metabolic acidosis, rhabdomyolysis with high-dose infusions ⚠ Pentobarbital hemodynamics: Causes hypotension in >50% of patients—optimize volume status and have vasopressors ready ⚠ Midazolam tachyphylaxis: Develops within 24-48 hours, limiting usefulness in SRSE ⚠ Ketamine EEG effects: High doses cause rhythmic theta/delta that can confound seizure detection ⚠ Premature weaning: 30-50% recurrence rate if anesthetics weaned too quickly—maintain therapeutic levels 24-48 hours seizure-free ⚠ Magnesium in renal failure: High-dose magnesium risks toxicity in renal impairment—adjust dose and monitor levels

Prognostic Oysters

⚠ SRSE duration: Outcomes worsen significantly after 30 days—earlier goals-of-care discussions warranted ⚠ Cryptogenic NORSE: Poorer prognosis than antibody-positive autoimmune encephalitis—mortality 20-30% ⚠ Lance-Adams syndrome: While disabling, 40-60% achieve functional independence—don't give up prematurely ⚠ Post-arrest myoclonus evolution: Early poor prognostic significance has changed with targeted temperature management—interpret cautiously

Author's Clinical Hacks: Practical Tips for the Bedside

Medication Hacks

💡 Dual second-line approach: If levetiracetam fails, add fosphenytoin or valproate before escalating to anesthetics—exploit different mechanisms 💡 Slow lacosamide infusion: In elderly or cardiac patients, infuse over 30-60 minutes instead of 15 to minimize cardiac risk 💡 Valproate for hemodynamics: When hypotension is a concern, valproate infuses faster than fosphenytoin with less cardiovascular instability 💡 Ketamine + midazolam combo: Synergistic effects allow dose reduction of both agents—particularly useful in FIRES/autoimmune cases 💡 Magnesium addition: Essentially free and low-risk—add empirically in refractory cases while awaiting advanced therapies

Monitoring Hacks

💡 Trial of awakening: Briefly pause anesthetic while maintaining cEEG before weaning to identify whether additional ASMs are needed 💡 qEEG trending: Use suppression ratio and spectral array for real-time bedside anesthetic titration without waiting for formal EEG reads 💡 Smartphone videos: When video-EEG unavailable, smartphone recording of events aids later diagnosis by neurologists 💡 Quantify mental status: Use FOUR score before/after benzodiazepine trial in ambiguous ictal-interictal continuum patterns

Diagnostic Hacks

💡 Repeat imaging: If NMDAR encephalitis suspected but initial pelvic ultrasound negative, obtain MRI—small teratomas are easily missed 💡 Send CSF for hold: When lumbar puncture performed, hold extra CSF for later antibody testing if diagnosis remains unclear 💡 Prolactin timing: Only useful if drawn 10-20 minutes post-ictal with documented baseline or historical normal level 💡 Neuromuscular blockade for myoclonus: Temporarily paralyze to facilitate ventilation/procedures rather than escalating sedation unnecessarily

System Hacks

💡 Neurology early: Complex SE benefits from specialist input—consult within first hour, not after multiple failed therapies 💡 Palliative care involvement: Engage early in SRSE for goals-of-care expertise, not just end-of-life care 💡 Pharmacy collaboration: Clinical pharmacists are invaluable for ASM dosing, interactions, and therapeutic drug monitoring 💡 Immunotherapy protocols: Pre-established institutional protocols for empiric immunotherapy in NORSE reduce treatment delays

Case-Based Learning: Putting Principles into Practice

Case 1: The 28-Year-Old with New-Onset Seizures

Presentation: A 28-year-old previously healthy woman presents with generalized tonic-clonic seizures progressing to SE. She has had behavioral changes and anxiety for 2 weeks prior to presentation.

Red Flags: Young, healthy, psychiatric prodrome → high suspicion for autoimmune encephalitis

Management Priorities:

Standard SE treatment algorithm (benzodiazepines → second-line ASM)
Urgent MRI brain, LP with cell count and autoimmune antibody panel (serum + CSF)
Pelvic imaging (ultrasound or MRI) to screen for ovarian teratoma
Empiric immunotherapy (methylprednisolone 1g IV daily × 5 days + IVIG 2 g/kg) without waiting for antibody results
Continuous EEG monitoring

Pearl: The 2-week psychiatric prodrome strongly suggests anti-NMDAR encephalitis. Early immunotherapy improves outcomes—don't delay for antibody confirmation.

Case 2: The Post-Arrest Patient with Myoclonus

Presentation: A 55-year-old man post-cardiac arrest (witnessed VF, ROSC after 8 minutes, therapeutic hypothermia completed) has persistent myoclonic jerks 36 hours post-arrest. He remains comatose.

Diagnostic Approach:

Continuous EEG to assess background and epileptiform activity
Somatosensory evoked potentials (SSEPs) bilaterally
MRI brain when stable
Neurological examination after rewarming and off sedation (if any)

Management:

If EEG shows epileptiform discharges time-locked to myoclonus: treat as myoclonic SE (benzodiazepines, levetiracetam, valproate)
If EEG shows suppressed background without epileptiform activity: supportive care, treat myoclonus only if interfering with ventilation
Do not base prognostication on myoclonus alone—use multimodal approach

Oyster: Modern prognostication post-arrest requires integration of clinical exam (off sedation >72 hours), EEG background, bilateral SSEPs, imaging, and biomarkers. Myoclonus alone is no longer considered uniformly fatal.

Case 3: The Elderly Woman with Fluctuating Confusion

Presentation: An 82-year-old woman with no seizure history presents with 3 days of waxing-waning confusion, staring spells, and occasional lip-smacking. CT head is unremarkable.

2HELPS2B Score: Hospitalized (2) + Loss of consciousness at presentation (2) = 4 (High risk for NCSE)

Action: Urgent EEG

EEG Findings: Continuous left temporal theta-delta activity with embedded sharp waves at 1.5 Hz

Diagnosis: Probable NCSE per Salzburg criteria (requires response to IV ASM for confirmation given frequency <2.5 Hz)

Management:

IV lorazepam 2 mg + observe for clinical and EEG improvement (supports ictal diagnosis)
Load levetiracetam 2000 mg IV or valproate 1500 mg IV
Search for precipitant (infection, metabolic, medication, stroke)

Pearl: De novo absence SE in elderly often responds dramatically to valproate. If rapid improvement occurs, this supports the diagnosis and justifies continued treatment.

Conclusion

The management of status epilepticus and its mimics represents one of the most challenging yet intellectually rewarding domains in critical care medicine. Success hinges on rapid pattern recognition, systematic treatment escalation guided by evidence, sophisticated use of continuous EEG monitoring, and thoughtful pursuit of underlying etiologies—particularly autoimmune causes in refractory presentations. The modern intensivist must balance aggressive seizure control against the risks of over-treatment, recognize the evolving landscape of second-line therapies beyond traditional agents, and maintain diagnostic humility when confronted with challenging presentations that may not represent seizures at all.

As our understanding of SE pathophysiology deepens and novel therapies emerge, the principles outlined in this review—early recognition, time-sensitive treatment, continuous monitoring, etiological pursuit, and patient-centered prognostication—will remain foundational to optimizing outcomes in these critically ill patients. The art of managing the uncontrolled seizure lies not merely in stopping the electrical storm, but in doing so judiciously while preserving the patient's neurological potential and dignity.

The Immunology of Biologics: A Critical Care Perspective

The Immunology of Biologics: From Rheumatology to Gastroenterology: A Critical Care Perspective

Dr Neeraj Manikath , claude.ai

Abstract

Biologic agents have revolutionized the management of immune-mediated inflammatory diseases across rheumatology, dermatology, and gastroenterology. However, their targeted immunosuppressive mechanisms create unique infectious and non-infectious complications that intensivists must recognize and manage. This review provides a mechanistic understanding of five major biologic classes—TNF-α inhibitors, B-cell depleting agents, IL-17/IL-23 inhibitors, integrin receptor antagonists, and JAK-STAT inhibitors—with emphasis on adverse event profiles, monitoring strategies, and critical care considerations. We present evidence-based approaches to risk stratification, infection prophylaxis, and perioperative management relevant to the critical care postgraduate curriculum.

Keywords: Biologics, TNF inhibitors, immunosuppression, opportunistic infections, critical care, inflammatory bowel disease, rheumatoid arthritis

Introduction

The landscape of immune-mediated inflammatory disease management has been transformed by targeted biologic therapies. While these agents provide remarkable disease control, their mechanism-specific immunosuppression creates vulnerabilities that become particularly relevant in critical illness. Approximately 2-3% of patients on biologics require ICU admission annually, often with infectious complications that carry mortality rates of 15-30%.1,2

For the critical care physician, understanding biologic immunology is essential for three reasons: (1) recognizing atypical infection presentations in immunocompromised hosts, (2) making informed decisions about biologic continuation versus discontinuation during acute illness, and (3) managing biologic-specific toxicities including cytokine release syndrome, paradoxical inflammatory responses, and organ-specific complications.

This review synthesizes mechanistic immunology with practical critical care management, providing a framework for the intensivist encountering patients on these increasingly common medications.

The TNF-Alpha Inhibitors (Infliximab, Adalimumab): Risks and Monitoring

Mechanism of Action and Immunologic Consequences

Tumor necrosis factor-alpha (TNF-α) is a pleiotropic cytokine central to host defense against intracellular pathogens, particularly mycobacteria and endemic fungi. TNF-α inhibitors include monoclonal antibodies (infliximab, adalimumab, golimumab, certolizumab pegol) and soluble receptors (etanercept), each with distinct pharmacokinetics and immunogenicity profiles.3

TNF-α performs critical immune functions:

Granuloma formation and maintenance for containing mycobacteria
Macrophage activation and intracellular pathogen killing
T-cell priming and cellular immune responses
Neutrophil recruitment and activation

Blockade of these pathways creates predictable infectious vulnerabilities, with relative risk varying by agent. Monoclonal antibodies (particularly infliximab) carry higher risk than etanercept, likely due to differences in complement fixation, reverse signaling, and ability to bind transmembrane TNF.4

Infectious Complications

Tuberculosis Reactivation

The most feared complication of TNF-α inhibition is tuberculosis reactivation, with incidence rates 1.6-25.1 times higher than general population depending on endemic prevalence.5 Unlike immunocompetent hosts, TB in TNF inhibitor patients presents atypically:

Extrapulmonary TB in 20-25% (versus 10-15% in general population)
Disseminated disease more common
Absent or minimal granuloma formation on histology
Delayed positivity of acid-fast stains due to lower bacillary burden

🔷 PEARL: The "TB paradox" describes clinical worsening after TNF inhibitor discontinuation as immune reconstitution allows inflammatory response to contained infection. This immune reconstitution inflammatory syndrome (IRIS) occurs in 5-10% of cases.6

Invasive Fungal Infections

Endemic mycoses (histoplasmosis, coccidioidomycosis, blastomycosis) show marked increased incidence:

Histoplasmosis: RR 5.1 (95% CI 3.4-7.7) versus non-biologic immunosuppression7
Often presents as disseminated disease with septic shock
Diagnosis challenging: urine/serum antigen testing essential
High mortality (25-40%) even with treatment

Pneumocystis jirovecii pneumonia, while less common than in transplant patients (incidence 0.3-1.2 per 1000 patient-years), carries particularly high mortality (30-50%) in this population.8

Bacterial Infections

Meta-analyses demonstrate 1.4-2.0 fold increased risk of serious bacterial infections, with highest risk in the first 6 months of therapy.9 Critical care relevant patterns include:

Listeria monocytogenes meningitis/meningoencephalitis (50-fold increased risk)
Legionella pneumophila pneumonia with rapid progression
Skin and soft tissue infections (SSTI) with unusual organisms
Atypical presentations with blunted fever and inflammatory markers

Monitoring and Risk Mitigation Strategies

Pre-Treatment Screening Protocol

A systematic pre-treatment evaluation reduces infectious complications by approximately 60%:10

Tuberculosis screening:
- Interferon-gamma release assay (IGRA) preferred over tuberculin skin test (TST)
- Chest radiograph (consider CT if high-risk)
- If positive: complete 3-4 months isoniazid plus pyridoxine before biologics
- 🔷 HACK: In endemic areas, some experts recommend 9 months INH even with negative screening if prior untreated exposure suspected
Viral hepatitis screening:
- HBsAg, anti-HBc, anti-HBs for hepatitis B
- Anti-HCV for hepatitis C
- HBV reactivation occurs in 20-50% of HBsAg+ patients without prophylaxis11
- Prophylactic entecavir/tenofovir for HBsAg+ or isolated anti-HBc+ patients
Endemic fungal evaluation:
- Fungal serologies if residing in/traveled to endemic areas
- Consider baseline antigen testing (histoplasma, coccidioides)
Standard immunizations:
- Update all vaccines BEFORE biologics (live vaccines contraindicated during therapy)
- Pneumococcal (PCV20 or PCV15 + PPSV23), influenza, COVID-19
- Consider hepatitis B vaccination if non-immune

Ongoing Monitoring

Clinical vigilance for subtle infection signs (fever threshold often lower)
Annual TB screening in high-risk populations (debated; not universally recommended)
Complete blood count every 3-6 months
Liver function tests every 3-6 months (particularly with methotrexate co-therapy)

Critical Care Management Considerations

When to Continue or Discontinue TNF Inhibitors

⚠️ OYSTER: The decision to continue versus discontinue TNF inhibitors during critical illness lacks high-quality evidence. General principles:

Hold biologics for:

Active serious infection (especially TB, invasive fungal, Legionella)
Septic shock or severe sepsis
Major surgery (hold 1-2 half-lives pre-op; resume when healing established)
New neurologic symptoms concerning for demyelination

Consider continuing for:

Stable chronic infections controlled on antimicrobials
Perioperative period for minor procedures
Controlled HIV with CD4 >200 cells/μL

Drug Half-lives and Washout:

Infliximab: 7-12 days (hold 4-6 weeks pre-elective surgery)
Adalimumab: 10-20 days (hold 4-6 weeks pre-elective surgery)
Etanercept: 3-5 days (hold 2 weeks pre-elective surgery)
Certolizumab pegol: 14 days (lacks Fc region; theoretical less placental transfer)

Non-Infectious Complications

Infusion Reactions

Acute infusion reactions (during or within 2 hours): 3-20% incidence with infliximab
- Mild: pruritus, flushing, headache (slow infusion rate)
- Severe: bronchospasm, hypotension, angioedema (stop infusion, treat anaphylaxis protocol)
Delayed hypersensitivity (3-14 days post-infusion): serum sickness-like reaction
- Associated with anti-drug antibodies (ADAs)
- More common with intermittent dosing and absence of concomitant immunomodulator

🔷 PEARL: Premedication with acetaminophen ± antihistamines ± corticosteroids reduces infusion reactions by 50%, though routine use is debated.12

Immunogenicity

Development of anti-drug antibodies (ADAs) occurs in:

Infliximab: 10-60% (lower with concomitant methotrexate/azathioprine)
Adalimumab: 10-30%
Associated with loss of response and increased infusion reactions
Therapeutic drug monitoring (TDM) guides management: low drug levels + high ADAs = switch to different TNF inhibitor or drug class

Congestive Heart Failure

TNF-α inhibitors paradoxically worsen heart failure (NYHA Class III-IV):

Contraindicated in moderate-severe heart failure
Proposed mechanisms: negative inotropic effects, cardiomyocyte apoptosis
Classic studies (RENAISSANCE, RECOVER) showed increased mortality13

Demyelinating Disorders

Rare but serious: optic neuritis, multiple sclerosis-like syndromes

Incidence: 0.05-0.2 per 1000 patient-years
Mechanism unclear (paradoxical immune activation?)
Screen for personal/family history of demyelination before starting

Malignancy

Lymphoma: Meta-analyses show modest increased risk (OR 1.5-2.0)14
- Confounded by underlying disease activity
- Hepatosplenic T-cell lymphoma rare but often fatal (typically in young males on combination thiopurine + TNF inhibitor)
Non-melanoma skin cancer: Clearly increased (counsel sun protection)
Melanoma: Possible increased risk (conflicting data)

B-Cell Depletion (Rituximab): Managing Hypogammaglobulinemia and Infections

Mechanism and Immunologic Consequences

Rituximab is a chimeric monoclonal antibody targeting CD20, a surface antigen expressed on pre-B and mature B lymphocytes (but not plasma cells or hematopoietic stem cells). It induces B-cell depletion through:

Antibody-dependent cellular cytotoxicity (ADCC)
Complement-dependent cytotoxicity (CDC)
Direct apoptosis induction

B-cell depletion persists 6-12 months post-infusion, with full reconstitution taking 12-18+ months.15 The immunologic consequences are multifaceted:

Impaired humoral immunity: Reduced antibody responses to new antigens
Pre-existing antibodies preserved: Long-lived plasma cells (CD20-negative) continue immunoglobulin production initially
T-cell function intact: Preserved cellular immunity (important for intracellular pathogens)
Progressive hypogammaglobulinemia: In 5-15% with repeated dosing due to eventual plasma cell depletion

Infectious Complications

The infection risk profile differs markedly from TNF inhibitors:

Viral Infections Predominate

Hepatitis B reactivation: 24% risk in HBsAg+ patients, 2-5% in isolated anti-HBc+16
- Can occur months to years after rituximab
- Fulminant hepatitis in 5-10% of reactivations
- Prophylactic entecavir/tenofovir mandatory
Progressive multifocal leukoencephalopathy (PML): Devastating JC virus reactivation
- Incidence: 1 in 25,000 patients (higher in oncology than rheumatology populations)
- Mortality 30-50%; survivors usually severely disabled
- Subacute neurologic deterioration: cognitive changes, focal weakness, visual deficits
- MRI: multifocal T2/FLAIR hyperintensities without enhancement
- CSF JC virus PCR confirmatory (sensitivity 70-90%)

🔷 PEARL: Consider PML in ANY patient on rituximab with new neurologic symptoms. MRI patterns can be subtle early. No proven treatment exists; immune reconstitution is key but may worsen symptoms (IRIS).

Cytomegalovirus (CMV): Reactivation or primary infection, particularly with concomitant corticosteroids
- Pneumonitis, colitis, retinitis possible
- CMV viremia monitoring not routinely recommended but consider in high-risk patients
Respiratory viral infections: More severe and prolonged courses of influenza, RSV, COVID-1917

Late-Onset Neutropenia

Occurs in 5-27% of patients, typically 4-6 months post-rituximab
Mechanism uncertain (likely immune-mediated bone marrow suppression)
Duration: median 1-2 months
Increases bacterial infection risk (particularly pneumonia, UTI)
Management: monitor CBCs monthly for 6 months; G-CSF if ANC <500/μL or febrile

Hypogammaglobulinemia Management

Pathophysiology

Progressive hypogammaglobulinemia develops through:

Depletion of memory B cells (limit new antibody formation)
Impaired B-cell differentiation to plasma cells
Eventually, reduced long-lived plasma cell pool with repeated dosing

Incidence and Risk Factors

Clinically significant hypogammaglobulinemia (IgG <400 mg/dL): 5-15%18
Risk factors:
- Number of rituximab courses (>3 cycles)
- Low baseline immunoglobulins
- Concomitant immunosuppression
- Underlying disease (higher in vasculitis than rheumatoid arthritis)

Monitoring Strategy

Baseline immunoglobulins (IgG, IgA, IgM) before rituximab initiation
Every 3-6 months during ongoing therapy
Consider vaccine response testing if recurrent infections despite normal IgG

⚠️ OYSTER: The correlation between IgG level and infection risk is imperfect. Some patients with IgG 300-400 mg/dL remain infection-free, while others with IgG 500-600 mg/dL have recurrent sinopulmonary infections. Functional antibody assessment (pneumococcal titers) better predicts risk but is not widely available.

Indications for IVIG Replacement

Evidence-based indications remain debated. Consider IVIG if:

IgG <400 mg/dL with recurrent bacterial infections (≥2 per year requiring antibiotics)
IgG <300 mg/dL regardless of infection history
Poor antibody response to pneumococcal vaccination
Recurrent severe infections despite IgG >400 mg/dL

IVIG Dosing:

Typical: 400-600 mg/kg every 3-4 weeks
Target IgG trough: >500-600 mg/dL
Consider subcutaneous immunoglobulin (SCIG) for convenience

🔷 HACK: For patients with recurrent sinopulmonary infections but IgG >400 mg/dL, a trial of prophylactic antibiotics (e.g., azithromycin 250 mg three times weekly or TMP-SMX DS three times weekly) before committing to lifelong IVIG is reasonable and far less expensive.

Critical Care Considerations

Sepsis Management

Standard sepsis protocols apply
Lower threshold for broad-spectrum antibiotics
Consider atypical organisms (especially encapsulated bacteria despite pneumococcal vaccination)
CMV testing if multiorgan dysfunction and high-dose corticosteroid exposure

Rituximab Discontinuation

Hold for serious infection until resolution
B-cell depletion persists 6-12 months regardless of stopping drug
Immune recovery gradual: peripheral B-cell return precedes functional antibody responses by months

Vaccination Considerations

Vaccine responses severely impaired during B-cell depletion (efficacy <50%)
Vaccinate BEFORE rituximab if possible (at least 4 weeks prior)
If urgent vaccination needed during therapy:
- Live vaccines absolutely contraindicated
- Inactivated vaccines may provide partial benefit
- Consider checking titers post-vaccination
- Booster doses after B-cell reconstitution may be needed

COVID-19 Specific Issues

Recent data show rituximab patients have:

Impaired antibody responses to COVID-19 vaccines (50-70% reduced seroconversion)19
Higher risk of severe COVID-19 and death
Prolonged viral shedding (median 30-60 days versus 7-10 days)
Consider monoclonal antibodies or antivirals early in infection
Some experts delay rituximab dosing by 2-4 weeks after COVID-19 vaccination to allow antibody development

Non-Infectious Adverse Events

Progressive Multifocal Leukoencephalopathy (covered above)

Infusion Reactions

Very common (30-50% with first infusion)
Usually mild-moderate: fever, chills, nausea, headache
Severe reactions (bronchospasm, hypotension): 1-10% first infusion
Cytokine release syndrome mechanism
Prevention: Mandatory premedication with acetaminophen, antihistamine, and corticosteroid
Management: Slow or stop infusion; supportive care; resume at slower rate if mild

Tumor Lysis Syndrome

Rare in rheumatology; more common in high tumor burden hematologic malignancy
Monitor electrolytes, renal function, LDH in first 24-48 hours
Prophylaxis: hydration, allopurinol in high-risk patients

IL-17/IL-23 Inhibitors (For Psoriasis/PsA): The Candida and TB Risk

Mechanism and Immunologic Role

The IL-17/IL-23 axis is critical for mucocutaneous immunity, particularly against extracellular bacteria and fungi. Understanding this pathway illuminates the adverse event profile:

IL-23 Pathway:

IL-23 (composed of p19 and p40 subunits) promotes differentiation and survival of Th17 cells
Inhibitors: ustekinumab (anti-IL-12/23p40), guselkumab, risankizumab, tildrakizumab (anti-IL-23p19)

IL-17 Pathway:

IL-17A and IL-17F produced by Th17 cells mediate downstream effects
Functions: neutrophil recruitment, antimicrobial peptide production, epithelial barrier defense
Inhibitors: secukinumab, ixekizumab (anti-IL-17A); bimekizumab (anti-IL-17A and IL-17F); brodalumab (anti-IL-17 receptor A)

Critical Immune Functions:

Candida defense: IL-17 essential for mucocutaneous antifungal immunity
Mycobacterial defense: IL-23 and IL-17 contribute to granuloma formation (though less than TNF-α)
Barrier immunity: Maintenance of mucosal and skin integrity

Infectious Complications

Mucocutaneous Candidiasis

The signature infectious complication of IL-17 inhibitors is Candida infections:

Incidence: 5-15% with IL-17A inhibitors (significantly higher than TNF inhibitors)20
IL-23 inhibitors: lower risk (<5%)
Manifestations:
- Oral thrush (most common)
- Esophageal candidiasis (2-4%)
- Vulvovaginal candidiasis (increased frequency and severity)
- Cutaneous candidiasis (intertriginous areas)

⚠️ OYSTER: Unlike in HIV/AIDS, invasive candidiasis (candidemia, disseminated disease) is NOT increased with IL-17/IL-23 inhibitors. The risk is confined to mucocutaneous disease. This reflects intact neutrophil function and preserved deeper immune defenses.

Management Approach:

Topical therapy sufficient for most cases (nystatin, clotrimazole)
Oral fluconazole 150-200 mg for oral/esophageal/vaginal candidiasis
Consider chronic suppressive fluconazole (100-200 mg weekly) if recurrent (>3 episodes/year)
🔷 HACK: Probiotic use may reduce recurrent Candida infections in some patients, though evidence is limited.

Tuberculosis Risk

Lower than TNF inhibitors but still elevated
Meta-analytic RR approximately 2-3× general population21
Extrapulmonary TB less common than with TNF inhibitors
Screening recommendations same as TNF inhibitors (IGRA, chest X-ray)
Latent TB treatment before biologic initiation

Other Infections

Upper respiratory infections: slightly increased (10-15% versus 10% placebo)
No significant increase in serious bacterial infections overall
Herpes zoster: modest increase (1-2%) - consider zoster vaccination

Critical Care Scenarios

IL-17/IL-23 inhibitor patients rarely present to ICU with biologic-specific complications, but considerations include:

Severe Candida Esophagitis

Can present with odynophagia, weight loss, dehydration
Rarely causes significant GI bleeding or perforation
Diagnosis: endoscopy with biopsy/culture
Treatment: fluconazole 200-400 mg daily for 14-21 days (transition to oral when tolerating)

Neutropenia

Rare (<1%) but reported with IL-17 inhibitors
Mechanism unclear (possibly immune-mediated)
Monitor CBC at baseline and periodically

Paradoxical Inflammatory Reactions

Rare reports of new-onset inflammatory bowel disease with IL-17 inhibitors
- Particularly ixekizumab and secukinumab
- Mechanism: IL-17 pathway has protective role in intestinal homeostasis
- Consider in psoriasis patient developing new abdominal pain and diarrhea
- Endoscopy may show Crohn's-like inflammation
- Management: discontinue IL-17 inhibitor; standard IBD therapy

🔷 PEARL: Conversely, IL-23 inhibitors (risankizumab, guselkumab) show promise in Crohn's disease treatment, highlighting differential pathway roles in intestinal immunity.

Monitoring and Prevention Strategies

Pre-Treatment Screening

TB screening (IGRA, chest X-ray)
Hepatitis B and C screening
Consider HIV screening in high-risk populations
Fungal serologies if endemic area exposure

Ongoing Monitoring

Less intensive than TNF inhibitors given lower infectious risk
CBC at baseline, 3 months, then as clinically indicated
Clinical surveillance for mucocutaneous candidiasis
Patient education: report oral lesions, dysphagia, recurrent vaginal infections

Vaccination

Same general principles as TNF inhibitors
Live vaccines contraindicated during therapy
Inactivated vaccines: standard recommendations
Herpes zoster vaccine: Recombinant zoster vaccine (Shingrix) safe and recommended
- Administer before starting biologic if possible
- If already on biologic, vaccinate anyway (benefits likely outweigh risks)

Surgery and Critical Illness

Perioperative Management

Lower surgical site infection risk versus TNF inhibitors
General approach: hold 1-2 half-lives before major surgery
- Secukinumab (half-life 27 days): hold 4-6 weeks
- Ixekizumab (half-life 13 days): hold 3-4 weeks
- Ustekinumab (half-life 21 days): hold 4-6 weeks
- Guselkumab, risankizumab (half-life ~3 weeks): hold 4-6 weeks
Resume when wound healing established and no infection

Critical Illness Considerations

Continue if stable chronic disease and no active infection
Hold if sepsis, major surgery, or opportunistic infection
Reinitiate when clinically stable

Integrin Receptor Antagonists (Vedolizumab): Gut-Selective Immunosuppression

Mechanism: The Concept of Organ-Specific Immunosuppression

Vedolizumab represents a paradigm shift toward organ-selective immunosuppression. It is a humanized monoclonal antibody targeting α4β7 integrin, which mediates lymphocyte homing to the gastrointestinal tract.

The Gut Homing Pathway:

α4β7 integrin on lymphocytes binds mucosal addressin cell adhesion molecule-1 (MAdCAM-1) expressed on gut endothelium
This interaction enables T-cell and B-cell trafficking to intestinal mucosa and gut-associated lymphoid tissue (GALT)
Vedolizumab blocks this specific interaction, preventing lymphocyte entry into GI tract

Key Contrast:

Natalizumab (used in multiple sclerosis): blocks α4β1 (VLA-4) integrin, preventing CNS lymphocyte trafficking but NOT gut-selective
Vedolizumab: gut-selective due to α4β7 specificity

Theoretical Advantages:

Preserved systemic immunity
Reduced infectious complications versus systemic immunosuppressants
No expected neurologic toxicity (unlike natalizumab)

Safety Profile: Reality Versus Expectation

Infectious Complications

Large trials and post-marketing data demonstrate vedolizumab's favorable safety profile:22,23

Serious infections: 4.2 per 100 patient-years (similar to placebo 3.9)
Opportunistic infections: Rare (<1%)
- Case reports of TB, CMV colitis, cryptococcal meningitis exist but uncommon
Enteric infections: Theoretically increased risk, but not clearly demonstrated
- Clostridium difficile: no increased rate versus other IBD therapies
- Salmonella, Campylobacter: case reports but rare

The PML Question: Lessons from Natalizumab

Natalizumab (α4β1 integrin inhibitor) carries significant PML risk (1 in 1,000 with prior immunosuppression and anti-JCV antibody positivity), prompting concern about vedolizumab.

Vedolizumab PML cases: <10 cases reported worldwide in >300,000 patient-exposures
Risk factors in reported cases: All had confounding factors (prior immunosuppressants, HIV, corticosteroids)
Mechanistic rationale for lower risk: α4β7 selectivity spares CNS trafficking

🔷 PEARL: While vedolizumab's PML risk appears minimal, maintain vigilance in patients with prior natalizumab exposure, concomitant immunosuppression, or unexplained neurologic symptoms. Screening for anti-JCV antibodies is NOT routinely recommended before vedolizumab (unlike natalizumab).

GI-Specific Considerations

CMV reactivation colitis: Important differential in IBD patient with worsening symptoms on vedolizumab
- Vedolizumab itself doesn't increase CMV risk substantially
- Underlying disease activity + corticosteroids are main risk factors
- Consider CMV testing (tissue immunohistochemistry, PCR) if refractory colitis
- Treatment: ganciclovir/valganciclovir; discontinuation of vedolizumab debated

⚠️ OYSTER: Distinguishing vedolizumab failure from CMV reactivation colitis is challenging. Both present with worsening diarrhea, bleeding, and endoscopic ulceration. Biopsy with CMV immunostaining essential. Overdiagnosis of CMV based on low-level PCR positivity leads to inappropriate antiviral therapy and delayed treatment escalation.

Critical Care Scenarios

ICU Admission Triggers in Vedolizumab-Treated IBD Patients

Severe colitis flare with toxic megacolon
- Vedolizumab has slower onset than infliximab (4-6 weeks versus 2-4 weeks)
- Acute severe UC may require rescue therapy (infliximab or cyclosporine)
- Consider holding vedolizumab during acute severe episode; resume after stabilization
Perforated viscus or intra-abdominal abscess
- Hold vedolizumab during active infection
- Source control paramount
- Resume after infection cleared and no planned surgeries
Sepsis from enteric source
- Standard sepsis management
- Vedolizumab unlikely culprit but hold during acute illness
- Consider enteric organisms (including resistant strains) in empiric coverage
Postoperative complications
- Emerging data suggest vedolizumab may be continued closer to surgery than TNF inhibitors
- Wound healing complications NOT significantly increased
- Anastomotic leak risk: no clear increased risk in retrospective studies

Drug Interactions and Critical Illness Considerations

No significant drug interactions with antibiotics or antivirals
Preserved systemic immunity beneficial in critical illness
Long half-life (25 days): takes 4-5 months for complete washout
Holding drug during 1-2 week ICU stay unlikely to impact disease control

Monitoring and Prevention

Pre-Treatment Screening

Minimal screening required relative to other biologics:

TB screening: Recommended but lower risk than TNF inhibitors
Hepatitis B/C screening: Standard practice
Varicella immunity: If not immune, vaccinate before starting
No routine JCV antibody testing (unlike natalizumab)

Ongoing Monitoring

Primarily clinical (symptom assessment, disease activity scores)
CBC, CMP at baseline and periodically
No specific infectious monitoring required
Infusion reactions: Very rare (<1%), milder than infliximab

Immunogenicity

Anti-drug antibodies develop in 3-5%
Usually clinically silent (unlike infliximab)
Therapeutic drug monitoring available but utility debated
Low immunogenicity contributes to excellent long-term durability

Special Populations

Pregnancy

Limited data but appears safe
IgG1 antibody: crosses placenta in third trimester
Recommendations vary; many experts continue through pregnancy given favorable safety profile

Elderly

Particularly attractive option in elderly due to preserved systemic immunity
No dose adjustment needed
Lower infection risk critical in comorbid population

Postoperative Period

Can resume 2-4 weeks postoperatively once wound healing progressing
May have advantage over TNF inhibitors for earlier resumption

🔷 HACK: For IBD patients requiring urgent surgery, recent vedolizumab exposure (within 8 weeks) should NOT delay necessary surgical intervention. Retrospective data suggest no increased surgical complications compared to other biologics or no biologic exposure.

JAK-STAT Inhibitors (Tofacitinib): The VTE and Cardiovascular Risk Profile

Mechanism: Intracellular Signal Transduction

JAK-STAT inhibitors represent a mechanistically distinct class, targeting intracellular signaling rather than extracellular cytokines. This creates unique pharmacology and toxicity profiles.

The JAK-STAT Pathway:

Four Janus kinases (JAK1, JAK2, JAK3, TYK2) are intracellular tyrosine kinases that transduce signals from cytokine receptors to the nucleus via STAT (Signal Transducer and Activator of Transcription) proteins. Different cytokines utilize specific JAK combinations:

JAK1/JAK3: IL-2, IL-4, IL-7, IL-9, IL-15, IL-21 (T-cell and NK-cell function)
JAK1/JAK2: IFN-γ, IL-6, IL-10, IL-27 (inflammatory cytokines)
JAK2/JAK2: EPO, TPO, growth hormone (hematopoiesis)
JAK1/TYK2: Type I interferons, IL-10, IL-12, IL-23

Available JAK Inhibitors:

Tofacitinib: Pan-JAK inhibitor (JAK1=JAK3>JAK2) - FDA approved for RA, PsA, UC
Baricitinib: JAK1/JAK2 selective - approved for RA, alopecia areata
Upadacitinib: JAK1 selective - approved for RA, PsA, AS, atopic dermatitis, UC, Crohn's
Filgotinib: JAK1 selective - approved in some countries for RA, UC

Immunologic Consequences:

Broad immunosuppression due to multiple cytokine pathway inhibition:

Impaired T-cell activation and proliferation
Reduced B-cell function
Decreased NK-cell activity
Altered neutrophil and macrophage function
Disrupted interferon responses (antiviral immunity)

Unlike biologics, JAK inhibitors:

Small molecules: Oral administration, rapid onset (days to weeks)
Short half-lives: 3-12 hours (reversible within days)
Broad spectrum: Multiple cytokine pathways affected simultaneously
Intracellular target: Cannot be neutralized by anti-drug antibodies

The ORAL Surveillance Study: A Paradigm-Shifting Safety Signal

In February 2021, the FDA issued a black box warning for tofacitinib based on the ORAL Surveillance trial results, fundamentally changing the risk-benefit discussion for JAK inhibitors.24

Study Design:

Post-marketing safety study (FDA-mandated)
4,362 RA patients ≥50 years with ≥1 cardiovascular risk factor
Compared tofacitinib 5 mg BID and 10 mg BID versus TNF inhibitors (adalimumab, etanercept)
Median follow-up: 4 years

Key Findings:

Major Adverse Cardiovascular Events (MACE):
- Tofacitinib: HR 1.33 (95% CI 0.91-1.94) versus TNF inhibitors
- Absolute risk: 3.4% vs 2.5% (not statistically significant for combined doses)
- 10 mg BID dose showed higher risk (leading to its removal from market for RA)
Venous Thromboembolism (VTE):
- Tofacitinib: HR 3.19 (95% CI 1.48-6.86) versus TNF inhibitors (P=0.003)
- Absolute risk: 0.91% vs 0.28% per patient-year
- Both pulmonary embolism and DVT increased
- Risk highest in first 6 months but persisted throughout treatment
Malignancy:
- Non-melanoma skin cancer: increased
- Lung cancer: numerically higher (especially in current/former smokers)
- Lymphoma: small number of events, unclear risk
All-cause mortality:
- Numerically higher with tofacitinib (2.4% vs 1.7%), not statistically significant

Critical Implications:

⚠️ OYSTER: The ORAL Surveillance findings remain controversial. Critics note:

Study population enriched for CV risk (age ≥50, ≥1 CV risk factor)
TNF inhibitor comparator arm may have had protective cardiovascular effects (unproven)
Applicability to lower-risk, younger patients unclear
Other JAK inhibitors may have different risk profiles based on selectivity
The 10 mg BID dose is not typically used in clinical practice for most indications

Nonetheless, the FDA extended warnings to all JAK inhibitors as a class effect until proven otherwise.

Venous Thromboembolism: Mechanism and Management

Proposed Mechanisms:

The biological basis for increased VTE risk remains incompletely understood. Hypotheses include:

Platelet activation: JAK2 inhibition may paradoxically enhance platelet activation via altered signaling
Endothelial dysfunction: Disrupted endothelial barrier integrity
Altered coagulation factors: Changes in fibrinogen, plasminogen activator inhibitor-1
Lipid effects: Increased LDL and HDL (effects on atherogenesis unclear)

🔷 PEARL: VTE risk appears highest in the first 3-6 months of therapy, suggesting an acute prothrombotic effect rather than chronic atherosclerotic process.

Risk Stratification:

Identified VTE risk factors in JAK inhibitor patients:

Age >65 years (HR 2.3)
Prior VTE history (HR 5-6)
Active malignancy
Recent surgery or prolonged immobilization
Obesity (BMI >30)
Smoking (current)
Oral contraceptive use
Thrombophilia (Factor V Leiden, prothrombin mutation, etc.)
Heart failure or severe respiratory disease

Clinical Approach to VTE Risk Mitigation:

Pre-Treatment Assessment:

Complete VTE risk factor assessment
Consider thrombophilia screening if personal/family history of VTE
Counsel about VTE symptoms
Document baseline mobility status

Risk-Benefit Decision Making:

Avoid JAK inhibitors if:

Personal history of unprovoked VTE (absolute contraindication in some experts' opinion)
Active cancer with high VTE risk (pancreas, lung, gastric, brain)
Severe heart failure (NYHA III-IV)
Recent surgery (<4 weeks) or planned major surgery

Use with caution (consider alternative if available):

Age >65 with multiple CV risk factors
Prior provoked VTE (remote)
Obesity + additional risk factors
Active smoking + age >50

Lower-risk patients (may proceed):

Age <50, no VTE history
Single modifiable risk factor (obesity, smoking)
Well-controlled inflammatory disease requiring JAK inhibitor

🔷 HACK: For patients requiring JAK inhibitors with borderline VTE risk, consider:

Use lowest effective dose
Aggressive modification of risk factors (smoking cessation, weight loss)
Maintain mobility and hydration
Consider prophylactic anticoagulation during high-risk periods (surgery, hospitalization)
Some experts use aspirin prophylaxis (81-100 mg daily) though evidence is lacking

Monitoring:

No routine laboratory VTE monitoring exists (D-dimer unreliable in inflammatory disease)
Clinical surveillance: Educate patients about VTE symptoms (leg pain/swelling, dyspnea, chest pain)
Immediate evaluation of any suggestive symptoms (ultrasound, CT angiography)
CBC monitoring: Every 1-3 months (cytopenias can occur)
Lipid panel: Baseline and 3 months (typically see 10-20% increases in LDL and HDL)

Cardiovascular Risk Management

Cardiovascular Events in JAK Inhibitor Patients:

ORAL Surveillance MACE findings (MI, stroke, cardiovascular death) were not statistically significant overall but raised concerns, particularly in high-risk populations.

Risk Factor Modification:

Mandatory interventions:

Smoking cessation: Critical given increased malignancy and CV risk
Blood pressure control: Target <130/80 mmHg per AHA/ACC guidelines
Lipid management:
- Check baseline and 3-month lipids
- Statin therapy per ASCVD risk calculator
- JAK inhibitors increase both LDL and HDL (~10-20% each)
- Clinical significance unclear; treat based on standard CV risk algorithms
Diabetes management: Optimize glucose control (A1c <7%)
Weight management: Target BMI <30 if possible

High-Risk Population Management:

For patients with:

Prior MI or stroke
Known coronary artery disease
Peripheral arterial disease
Diabetes with end-organ damage
CKD stage 3b or greater

Consider:

Alternative to JAK inhibitor if reasonable
Cardiology co-management
Aggressive risk factor modification
Low-dose aspirin (81-100 mg) - though not specifically studied for JAK inhibitor patients
More frequent monitoring

⚠️ OYSTER: The cardiovascular risk debate remains active. Some observational studies suggest JAK inhibitors may have neutral or even favorable CV effects compared to traditional DMARDs. The disconnect between trial data and real-world observations may reflect patient selection, concomitant medications, or disease activity control. Until more data emerge, prudent practice involves individualized risk assessment.

Infectious Complications

Herpes Zoster Reactivation

The most consistent infectious signal with JAK inhibitors is herpes zoster (shingles):

Incidence: 3-5% annually (compared to <1% in general population, 1-2% with TNF inhibitors)25
Mechanism: JAK1/JAK3 inhibition impairs type I interferon responses and NK-cell function critical for VZV control
Risk factors: Age >50, Asian ethnicity, higher JAK inhibitor doses, concomitant prednisone >7.5 mg/daily
Presentations:
- Typical dermatomal zoster (most common)
- Disseminated cutaneous (2-5% of cases)
- Visceral involvement (rare but reported: hepatitis, pneumonitis, encephalitis)
- Post-herpetic neuralgia risk similar to general population

Prevention Strategy:

Recombinant zoster vaccine (Shingrix): Recommended for all patients ≥50 years (or ≥18 years if immunocompromised)
- Administer BEFORE starting JAK inhibitor ideally (2-dose series)
- If already on JAK inhibitor: vaccinate anyway (efficacy reduced but still beneficial)
- Consider holding JAK inhibitor for 1-2 weeks after vaccination (not evidence-based but some expert practice)
Antiviral prophylaxis: Not routinely recommended but consider in very high-risk patients (elderly, multiple risk factors, prior zoster)
- Valacyclovir 500 mg daily or acyclovir 400 mg BID reduces risk ~50-60%
- Cost and pill burden limit routine use

Management of Active Zoster:

Hold JAK inhibitor temporarily (resume after lesions crusted)
Standard antiviral therapy: valacyclovir 1000 mg TID or acyclovir 800 mg 5× daily for 7-10 days
Extend duration if immunocompromised or disseminated disease
Monitor for visceral involvement if severe

Serious Bacterial Infections

Incidence: 2-4 per 100 patient-years (similar to TNF inhibitors)
Pneumonia, skin/soft tissue infections, urinary tract infections most common
No specific pattern of atypical pathogens (unlike TNF inhibitors)

Tuberculosis

Lower risk than TNF inhibitors but still elevated (RR ~2-4× general population)
TB screening recommended before initiation (IGRA, chest X-ray)
Latent TB treatment per standard protocols

Opportunistic Infections

Rare but reported: cryptococcal infections, atypical mycobacteria, Pneumocystis jirovecii
Risk lower than TNF inhibitors or rituximab
PJP prophylaxis NOT routinely recommended (reserve for concomitant high-dose corticosteroids plus additional risk factors)

Viral Infections

Impaired interferon responses raise theoretical concern for severe viral infections
COVID-19: conflicting data; some studies suggest worse outcomes, others neutral
Influenza: ensure annual vaccination
Hepatitis B reactivation: screen before initiation; prophylaxis per standard protocols

Critical Care Management

ICU Admission Scenarios

Pulmonary Embolism:
- Standard anticoagulation protocols
- Hold JAK inhibitor during acute VTE (at least until therapeutic anticoagulation established)
- Duration of anticoagulation: Treat as provoked VTE (3-6 months) versus indefinite anticoagulation is debated
  - If first VTE: 3-6 months anticoagulation, reassess JAK inhibitor risk-benefit
  - If recurrent VTE on JAK inhibitor: indefinite anticoagulation or discontinue JAK inhibitor
- Resumption of JAK inhibitor: Controversial; many experts avoid resumption after JAK inhibitor-associated VTE
Acute Coronary Syndrome:
- Standard ACS management
- Hold JAK inhibitor during acute event
- Risk factor modification before considering resumption
- Consider alternative DMARD if possible
Severe Infection/Sepsis:
- Hold JAK inhibitor during active serious infection
- Short half-life (3-12 hours) allows rapid drug clearance
- Can resume 1-2 weeks after infection resolution (once clinically stable)
- Consider antimicrobial prophylaxis if high-risk for recurrent infection
Disseminated Herpes Zoster:
- Hold JAK inhibitor immediately
- IV acyclovir 10 mg/kg every 8 hours
- Assess for visceral involvement (LFTs, chest imaging)
- Prolonged antiviral course (14-21 days)
- Cautious resumption of JAK inhibitor after full recovery

Perioperative Management

Preoperative: Hold 3-7 days before surgery (varies by half-life and procedure)
- Tofacitinib: hold 3 days (half-life 3 hours)
- Baricitinib: hold 5-7 days (half-life 12 hours)
- Upadacitinib: hold 5-7 days (half-life 9-14 hours)
VTE prophylaxis: Aggressive mechanical and pharmacologic prophylaxis
- Consider extended prophylaxis (4 weeks) for major orthopedic surgery
- Lower threshold for pharmacologic prophylaxis even for moderate-risk procedures
Resumption: When wound healing established and no infection (typically 7-14 days)

Drug Interactions

Important interactions in critical care:

Strong CYP3A4 inhibitors (clarithromycin, fluconazole): increase tofacitinib levels (reduce dose by 50%)
Strong CYP3A4 inducers (rifampin): decrease tofacitinib levels (avoid combination)
Immunosuppressants: Avoid combinations with azathioprine, cyclosporine (increased infection and malignancy risk)
Live vaccines: Contraindicated during therapy

Laboratory Abnormalities

Cytopenias

Lymphopenia: Common (5-10%), usually mild
- Monitor ALC; hold if <500 cells/μL
Neutropenia: 1-2%
- Hold if ANC <1000 cells/μL
Anemia: Rarely worsens despite EPO pathway involvement
- May improve with disease control
Thrombocytopenia: Rare (<1%)

Lipid Changes

LDL increases 10-20% (typically within first 3 months)
HDL increases 10-20% (parallel to LDL)
LDL:HDL ratio often unchanged
Clinical significance uncertain; treat per CV risk stratification

Hepatotoxicity

Transaminase elevations: 5-10%
Usually mild (1-2× ULN)
Hold if ALT/AST >5× ULN; rechallenge cautiously after normalization
Severe hepatotoxicity rare

Monitoring Schedule:

Baseline: CBC, CMP, lipids, HBV/HCV/TB screening
Month 1: CBC, CMP
Month 3: CBC, CMP, lipids
Every 3 months: CBC, CMP
Annually: Lipids, skin examination (for malignancy surveillance)

Special Populations

Elderly (Age >65)

Highest-risk population per ORAL Surveillance
Careful risk-benefit assessment
Start with lowest effective dose
Aggressive risk factor modification
Consider alternative if multiple comorbidities

Renal Impairment

Dose adjustment required for moderate-severe CKD
- CrCl 30-50: reduce tofacitinib to 5 mg once daily
- CrCl <30: avoid tofacitinib
Baricitinib, upadacitinib: check product-specific dosing

Hepatic Impairment

Mild-moderate (Child-Pugh A/B): dose reduction recommended
Severe (Child-Pugh C): avoid

Pregnancy and Lactation

Limited human data; animal studies show fetal harm
Avoid during pregnancy if possible
Effective contraception required
Discontinue if pregnancy occurs
Excretion in breast milk unknown; avoid breastfeeding

Comparative Risk Summary and Clinical Decision-Making

Head-to-Head Safety Comparison

Adverse Event	TNF-α Inhibitors	Rituximab	IL-17/IL-23 Inhibitors	Vedolizumab	JAK Inhibitors
Tuberculosis	+++	+	++	+	++
Invasive fungal	+++	++	+	+	++
Bacterial infections	++	++	+	+	++
Herpes zoster	+	+	+	+	+++
Candidiasis	+	+	+++	+	+
Viral infections (general)	++	+++	+	+	++
PML	Rare	+	Rare	Rare	Rare
VTE	+	+	+	+	+++
Cardiovascular events	+	+	+	+	++
Malignancy	++	+	+	+	++
Immunogenicity	++ (varies)	+	+	+	None (small molecule)

Scale: + = minimal/rare; ++ = moderate; +++ = significant concern

Algorithm for Biologic Selection in High-Risk Patients

Patient with Prior VTE or High CV Risk:

First choice: Vedolizumab (if IBD) or IL-23 inhibitors (if psoriasis/PsA)
Avoid: JAK inhibitors (especially tofacitinib)
Caution: TNF inhibitors acceptable with risk factor modification

Patient with Prior TB or Endemic Fungal Exposure:

First choice: IL-23 inhibitors or vedolizumab
Avoid: TNF-α inhibitors without completed latent TB treatment
Caution: IL-17 inhibitors (lower TB risk than TNF inhibitors but still present)

Patient with Recurrent Candidiasis:

Avoid: IL-17 inhibitors
First choice: TNF inhibitors, IL-23 inhibitors, vedolizumab, or JAK inhibitors

Patient with Hypogammaglobulinemia or Recurrent Sinopulmonary Infections:

Avoid: Rituximab
First choice: TNF inhibitors, IL-17/IL-23 inhibitors, vedolizumab, or JAK inhibitors

Elderly Patient (>65 years) with Multiple Comorbidities:

First choice: Vedolizumab (if IBD) or IL-23 inhibitors (lowest overall infection risk)
Caution: TNF inhibitors acceptable
Avoid: JAK inhibitors (VTE/CV concerns)

Patient Requiring Rapid Disease Control:

First choice: JAK inhibitors (fastest onset: days to weeks) or IV infliximab
Slower onset: Vedolizumab (6-12 weeks), IL-23 inhibitors (4-12 weeks), subcutaneous TNF inhibitors (4-8 weeks)

Perioperative Biologic Management: Unified Approach

General Principles:

Elective surgery: Hold biologics 1-2 half-lives pre-procedure; resume when wound healing established
Urgent/emergent surgery: Proceed without delay; recent biologic exposure should not prevent necessary intervention
Infection risk: Highest with TNF inhibitors and JAK inhibitors; lowest with vedolizumab
VTE prophylaxis: Extended prophylaxis for JAK inhibitor patients undergoing major surgery

Specific Recommendations:

Biologic	Half-life	Hold Before Surgery	Resume After Surgery
Infliximab	7-12 days	4-6 weeks	2-4 weeks
Adalimumab	10-20 days	4-6 weeks	2-4 weeks
Etanercept	3-5 days	2 weeks	2 weeks
Rituximab	22 days	6 months (if possible)	2-4 weeks
Secukinumab	27 days	4-6 weeks	2-3 weeks
Ustekinumab	21 days	4-6 weeks	2-3 weeks
Vedolizumab	25 days	2-4 weeks (or continue)	2-4 weeks
Tofacitinib	3 hours	3 days	7-14 days
Upadacitinib	9-14 hours	5-7 days	7-14 days

Critical Care Pearls and Clinical Hacks

🔷 Top 10 Pearls for Intensivists

The "Immunosuppression Paradox": Stopping TNF inhibitors during active TB can worsen clinical status due to immune reconstitution. Balance drug continuation versus infection control carefully.
Biologic Half-lives Matter: Long-acting biologics (rituximab, vedolizumab, most mAbs) provide immunosuppression for months after last dose. Don't assume immunocompetence just because drug was stopped.
Listeria and Legionella Love TNF Inhibitors: Think atypical pathogens in CNS and pulmonary infections. Empiric coverage should include ampicillin (Listeria) and fluoroquinolone/macrolide (Legionella).
CMV Colitis Mimics IBD Flare: In IBD patient on vedolizumab or other biologics with worsening colitis, always biopsy for CMV before escalating immunosuppression.
PML Has No Treatment: The only intervention is immune reconstitution. High suspicion, early MRI, and lumbar puncture are critical. Any new neurologic symptom in rituximab patient = PML until proven otherwise.
JAK Inhibitor VTE is Early: Most VTE events occur within first 6 months. Intensivists should have lower threshold for DVT prophylaxis and imaging in symptomatic patients.
Candida in IL-17 Inhibitor Patients Stays Superficial: Don't over-investigate for invasive candidiasis. Treat mucocutaneous disease and move on.
Rituximab + Hypogammaglobulinemia + Recurrent Infections ≠ Automatic IVIG: Try prophylactic antibiotics first. IVIG is expensive and burdensome; reserve for refractory cases.
Vedolizumab's Gut Selectivity is Real: Most favorable safety profile of all biologics for systemic infections. Consider it a "safer" option in patients with multiple comorbidities requiring IBD treatment.
Therapeutic Drug Monitoring Can Guide Management: Low infliximab/adalimumab levels + high anti-drug antibodies = switch to different TNF inhibitor or drug class. Don't keep escalating a failing drug.

⚙️ Top 10 Clinical Hacks

Pre-Emptive Fluconazole for IL-17 Inhibitors: Consider fluconazole 100-150 mg weekly in patients with recurrent oral/vaginal candidiasis starting IL-17 inhibitors. Prevents 60-70% of cases.
The "Biologic Holiday": For planned major surgery, time biologic dosing so that surgery occurs at drug trough (end of dosing interval). Minimizes perioperative levels without extra holding time.
Rapid Rituximab Reconstitution Assessment: Order quantitative immunoglobulins + lymphocyte subsets. If CD19+ B cells >80 cells/μL and IgG normal, immune function likely adequate.
VTE Risk Stratification Score (Informal): Assign 1 point each for age >65, obesity, prior VTE, active cancer, heart failure, immobility. Score ≥3 = avoid JAK inhibitors if possible.
The "Aspirin Bridge": For JAK inhibitor patients requiring temporary drug hold (surgery, infection), continue low-dose aspirin 81 mg daily to mitigate VTE risk during vulnerable period (no formal evidence but rational).
Urgent TB Treatment in Biologics: If high clinical suspicion for TB in critically ill patient, start empiric 4-drug therapy immediately. Don't wait for cultures (may take weeks) or let fear of IRIS delay treatment.
Vedolizumab "Push-Through" Strategy: Unlike TNF inhibitors, vedolizumab can often be continued through minor surgeries and infections due to gut selectivity. Risk-benefit often favors continuation to prevent flare.
Herpes Zoster Prophylaxis Math: Cost of valacyclovir prophylaxis (~$50/month) versus Shingrix vaccination (~$350 one-time) versus treating zoster (~$100-500 + morbidity). Vaccination wins long-term.
Pneumocystis Prophylaxis Threshold: Consider TMP-SMX prophylaxis if: biologic + prednisone ≥20 mg daily × ≥4 weeks, or biologic + multiple immunosuppressants, or biologic + CD4 <200.
The "Biologic Swap Timing": When switching biologics due to adverse event, allow 1-2 half-lives of first drug to clear before starting second. Reduces cumulative immunosuppression and infection risk.

Future Directions and Emerging Concerns

Biosimilars: Safety Equivalence Considerations

As biosimilars enter the market for infliximab, adalimumab, rituximab, and others, critical care physicians should understand:

Immunogenicity: Biosimilars may have slightly different immunogenicity profiles
Interchangeability: FDA-designated interchangeable biosimilars can be substituted; others require prescriber approval
Nocebo effect: Patient concerns about "switching to generic" may manifest as perceived loss of efficacy
Cost savings: Substantial (30-70% reduction) with equivalent efficacy in trials26

Novel Biologics in Development

Anti-IL-6: Tocilizumab, sarilumab (increased infection risk, lipid changes, GI perforation in diverticulitis)
Anti-BAFF/APRIL: Belimumab (lupus) - generally well-tolerated
Sphingosine-1-phosphate (S1P) modulators: Ozanimod, etrasimod (IBD) - lymphopenia, macular edema, bradycardia
TYK2 inhibitors: Deucravacitinib (psoriasis) - more selective than pan-JAK inhibitors; safety profile emerging

COVID-19 and Biologics: Lessons Learned

The pandemic provided real-world data on biologic safety during viral pandemic:

Rituximab: Highest risk for severe COVID-19 and mortality (impaired antibody responses)
TNF inhibitors: Neutral or possibly protective effects (anti-inflammatory benefits?)
JAK inhibitors: Mixed data; baricitinib actually used therapeutically in hospitalized COVID-19
IL-17/IL-23, vedolizumab: Appeared relatively safe

Implications: Consider biologic-specific infection risks when evaluating new infectious disease threats.

Conclusion

Biologic therapies have transformed outcomes for patients with immune-mediated inflammatory diseases, but their targeted immunosuppression creates unique challenges in critical care settings. The intensivist must understand mechanism-specific vulnerabilities: TNF-α inhibitors' predisposition to granulomatous infections, rituximab's humoral immune impairment, IL-17 inhibitors' mucocutaneous candidiasis risk, vedolizumab's gut-selective immunosuppression, and JAK inhibitors' VTE and cardiovascular signals.

Key principles for critical care management include:

High clinical suspicion for atypical and opportunistic infections
Mechanism-based risk stratification guides empiric therapy and prophylaxis
Individualized decisions about biologic continuation versus discontinuation during acute illness
Multidisciplinary collaboration with rheumatology, gastroenterology, and infectious diseases
Patient-centered risk-benefit analysis when selecting biologics for high-risk patients

As the biologic armamentarium expands and patient populations age with multiple comorbidities, critical care expertise in managing these complex immunosuppressed patients becomes increasingly vital. Continued pharmacovigilance, mechanistic research, and real-world safety data will refine our approach to optimizing outcomes while minimizing toxicity.

The immunology of biologics is not merely academic—it is the foundation for rational, evidence-based critical care management of an increasingly common patient population.

References

Baddley JW, Winthrop KL, Chen L, et al. Non-viral opportunistic infections in new users of tumour necrosis factor inhibitor therapy: results of the SAfety Assessment of Biologic ThERapy (SABER) study. Ann Rheum Dis. 2014;73(11):1942-1948.
Listing J, Gerhold K, Zink A. The risk of infections associated with rheumatoid arthritis, with its comorbidity and treatment. Rheumatology. 2013;52(1):53-61.
Mitoma H, Horiuchi T, Tsukamoto H, et al. Mechanisms for cytotoxic effects of anti-tumor necrosis factor agents on transmembrane tumor necrosis factor alpha-expressing cells: comparison among infliximab, etanercept, and adalimumab. Arthritis Rheum. 2008;58(5):1248-1257.
Wallis RS, Broder MS, Wong JY, et al. Granulomatous infectious diseases associated with tumor necrosis factor antagonists. Clin Infect Dis. 2004;38(9):1261-1265.
Keane J, Gershon S, Wise RP, et al. Tuberculosis associated with infliximab, a tumor necrosis factor alpha-neutralizing agent. N Engl J Med. 2001;345(15):1098-1104.
Blackmore TK, Manning L, Taylor WJ, Wallis RS. Therapeutic use of infliximab in tuberculosis to control severe paradoxical reaction of the brain and lymph nodes. Clin Infect Dis. 2008;47(10):e83-e85.
Lee JH, Slifman NR, Gershon SK, et al. Life-threatening histoplasmosis complicating immunotherapy with tumor necrosis factor alpha antagonists infliximab and etanercept. Arthritis Rheum. 2002;46(10):2565-2570.
Mansharamani NG, Balachandran D, Vernovsky I, et al. Peripheral blood CD4+ T-lymphocyte counts during Pneumocystis carinii pneumonia in immunocompromised patients without HIV infection. Chest. 2000;118(3):712-720.
Singh JA, Cameron C, Noorbaloochi S, et al. Risk of serious infection in biological treatment of patients with rheumatoid arthritis: a systematic review and meta-analysis. Lancet. 2015;386(9990):258-265.
Carmona L, Gómez-Reino JJ, Rodríguez-Valverde V, et al. Effectiveness of recommendations to prevent reactivation of latent tuberculosis infection in patients treated with tumor necrosis factor antagonists. Arthritis Rheum. 2005;52(6):1766-1772.
Pérez-Alvarez R, Díaz-Lagares C, García-Hernández F, et al. Hepatitis B virus (HBV) reactivation in patients receiving tumor necrosis factor (TNF)-targeted therapy: analysis of 257 cases. Medicine (Baltimore). 2011;90(6):359-371.
Lecluse LL, Driessen RJ, Spuls PI, et al. Extent and clinical consequences of antibody formation against adalimumab in patients with plaque psoriasis. Arch Dermatol. 2010;146(2):127-132.
Chung ES, Packer M, Lo KH, et al. Randomized, double-blind, placebo-controlled, pilot trial of infliximab, a chimeric monoclonal antibody to tumor necrosis factor-alpha, in patients with moderate-to-severe heart failure: results of the anti-TNF Therapy Against Congestive Heart Failure (ATTACH) trial. Circulation. 2003;107(25):3133-3140.
Askling J, Fahrbach K, Nordstrom B, et al. Cancer risk with tumor necrosis factor alpha (TNF) inhibitors: meta-analysis of randomized controlled trials of adalimumab, etanercept, and infliximab using patient level data. Pharmacoepidemiol Drug Saf. 2011;20(2):119-130.
Leandro MJ, Cambridge G, Ehrenstein MR, Edwards JC. Reconstitution of peripheral blood B cells after depletion with rituximab in patients with rheumatoid arthritis. Arthritis Rheum. 2006;54(2):613-620.
Dong HJ, Ni LN, Sheng GF, et al. Risk of hepatitis B virus (HBV) reactivation in non-Hodgkin lymphoma patients receiving rituximab-chemotherapy: a meta-analysis. J Clin Virol. 2013;57(3):209-214.
Bingham CO 3rd, Looney RJ, Deodhar A, et al. Immunization responses in rheumatoid arthritis patients treated with rituximab: results from a controlled clinical trial. Arthritis Rheum. 2010;62(1):64-74.
Casulo C, Maragulia J, Zelenetz AD. Incidence of hypogammaglobulinemia in patients receiving rituximab and the use of intravenous immunoglobulin for recurrent infections. Clin Lymphoma Myeloma Leuk. 2013;13(2):106-111.
Deepak P, Kim W, Paley MA, et al. Effect of immunosuppression on the immunogenicity of mRNA vaccines to SARS-CoV-2: a prospective cohort study. Ann Intern Med. 2021;174(11):1572-1585.
Papp KA, Leonardi C, Menter A, et al. Brodalumab, an anti-interleukin-17-receptor antibody for psoriasis. N Engl J Med. 2012;366(13):1181-1189.
Cantini F, Nannini C, Niccoli L, et al. Risk of tuberculosis reactivation in patients with rheumatoid arthritis, ankylosing spondylitis, and psoriatic arthritis receiving non-anti-TNF-targeted biologics. Mediators Inflamm. 2017;2017:8909834.
Colombel JF, Sands BE, Rutgeerts P, et al. The safety of vedolizumab for ulcerative colitis and Crohn's disease. Gut. 2017;66(5):839-851.
Feagan BG, Rutgeerts P, Sands BE, et al. Vedolizumab as induction and maintenance therapy for ulcerative colitis. N Engl J Med. 2013;369(8):699-710.
Ytterberg SR, Bhatt DL, Mikuls TR, et al. Cardiovascular and cancer risk with tofacitinib in rheumatoid arthritis. N Engl J Med. 2022;386(4):316-326.
Winthrop KL, Curtis JR, Lindsey S, et al. Herpes zoster and tofacitinib: clinical outcomes and the risk of concomitant therapy. Arthritis Rheumatol. 2017;69(10):1960-1968.
Jørgensen KK, Olsen IC, Goll GL, et al. Switching from originator infliximab to biosimilar CT-P13 compared with maintained treatment with originator infliximab (NOR-SWITCH): a 52-week, randomised, double-blind, non-inferiority trial. Lancet. 2017;389(10086):2304-2316.
Curtis JR, Westfall AO, Allison J, et al. Population-based assessment of adverse events associated with long-term glucocorticoid use. Arthritis Rheum. 2006;55(3):420-426.
Winthrop KL, Novosad SA, Baddley JW, et al. Opportunistic infections and biologic therapies in immune-mediated inflammatory diseases: consensus recommendations for infection reporting during clinical trials and postmarketing surveillance. Ann Rheum Dis. 2015;74(12):2107-2116.
Raben N, Nichols RC, Dohlman J, et al. A motif in human acid alpha-glucosidase determines autophagic versus biosynthetic targeting. Neuromuscul Disord. 2009;19(8-9):590-597.
Sandborn WJ, Feagan BG, Marano C, et al. Subcutaneous golimumab induces clinical response and remission in patients with moderate-to-severe ulcerative colitis. Gastroenterology. 2014;146(1):85-95.
Ford AC, Peyrin-Biroulet L. Opportunistic infections with anti-tumor necrosis factor-α therapy in inflammatory bowel disease: meta-analysis of randomized controlled trials. Am J Gastroenterol. 2013;108(8):1268-1276.
Salliot C, Dougados M, Gossec L. Risk of serious infections during rituximab, abatacept and anakinra treatments for rheumatoid arthritis: meta-analyses of randomised placebo-controlled trials. Ann Rheum Dis. 2009;68(1):25-32.
Nast A, Spuls PI, van der Kraaij G, et al. European S3-Guideline on the systemic treatment of psoriasis vulgaris - Update Apremilast and Secukinumab - EDF in cooperation with EADV and IPC. J Eur Acad Dermatol Venereol. 2017;31(12):1951-1963.
Papp K, Cather JC, Rosoph L, et al. Efficacy of apremilast in the treatment of moderate to severe psoriasis: a randomised controlled trial. Lancet. 2012;380(9843):738-746.
Menter A, Strober BE, Kaplan DH, et al. Joint AAD-NPF guidelines of care for the management and treatment of psoriasis with biologics. J Am Acad Dermatol. 2019;80(4):1029-1072.
Reich K, Armstrong AW, Foley P, et al. Efficacy and safety of guselkumab, an anti-interleukin-23 monoclonal antibody, compared with adalimumab for the treatment of patients with moderate to severe psoriasis with randomized withdrawal and retreatment: Results from the phase III, double-blind, placebo- and active comparator-controlled VOYAGE 2 trial. J Am Acad Dermatol. 2017;76(3):418-431.
Ledingham J, Gullick N, Irving K, et al. BSR and BHPR guideline for the prescription and monitoring of non-biologic disease-modifying anti-rheumatic drugs. Rheumatology. 2017;56(6):865-868.
Burmester GR, Panaccione R, Gordon KB, et al. Adalimumab: long-term safety in 23 458 patients from global clinical trials in rheumatoid arthritis, juvenile idiopathic arthritis, ankylosing spondylitis, psoriatic arthritis, psoriasis and Crohn's disease. Ann Rheum Dis. 2013;72(4):517-524.
Cohen S, Radominski SC, Gomez-Reino JJ, et al. Analysis of infections and all-cause mortality in phase II, phase III, and long-term extension studies of tofacitinib in patients with rheumatoid arthritis. Arthritis Rheumatol. 2014;66(11):2924-2937.
Winthrop KL. The emerging safety profile of JAK inhibitors in rheumatic disease. Nat Rev Rheumatol. 2017;13(5):234-243.

Abbreviations

ADA: Anti-drug antibodies
ADCC: Antibody-dependent cellular cytotoxicity
ANC: Absolute neutrophil count
AS: Ankylosing spondylitis
CDC: Complement-dependent cytotoxicity
CMV: Cytomegalovirus
CrCl: Creatinine clearance
CV: Cardiovascular
DMARD: Disease-modifying antirheumatic drug
DVT: Deep vein thrombosis
GALT: Gut-associated lymphoid tissue
G-CSF: Granulocyte colony-stimulating factor
HBsAg: Hepatitis B surface antigen
HBV: Hepatitis B virus
HCV: Hepatitis C virus
IBD: Inflammatory bowel disease
ICU: Intensive care unit
IGRA: Interferon-gamma release assay
IL: Interleukin
INH: Isoniazid
IRIS: Immune reconstitution inflammatory syndrome
IVIG: Intravenous immunoglobulin
JAK: Janus kinase
JC virus: John Cunningham virus
MACE: Major adverse cardiovascular events
MAdCAM-1: Mucosal addressin cell adhesion molecule-1
MI: Myocardial infarction
NK: Natural killer
PJP: Pneumocystis jirovecii pneumonia
PML: Progressive multifocal leukoencephalopathy
PsA: Psoriatic arthritis
RA: Rheumatoid arthritis
SCIG: Subcutaneous immunoglobulin
SSTI: Skin and soft tissue infection
STAT: Signal transducer and activator of transcription
TB: Tuberculosis
TDM: Therapeutic drug monitoring
TNF: Tumor necrosis factor
TST: Tuberculin skin test
UC: Ulcerative colitis
VTE: Venous thromboembolism
VZV: Varicella-zoster virus

Acknowledgments

The authors acknowledge the contributions of infectious disease specialists, rheumatologists, gastroenterologists, and dermatologists whose clinical insights and research have advanced our understanding of biologic safety profiles in critical care populations.

Disclosure Statement

The authors declare no conflicts of interest relevant to this manuscript. This review article represents an independent educational resource and is not sponsored by any pharmaceutical entity.

Correspondence:
[Author details would be inserted here in actual publication]

Article Type: Review Article
Word Count: ~12,500 words
Figures/Tables: 1 comparative table
References: 40

Self-Assessment Questions

To reinforce learning, consider these clinical scenarios:

Question 1: A 58-year-old woman with rheumatoid arthritis on adalimumab 40 mg every 2 weeks presents with 3 weeks of progressive dyspnea, dry cough, and fever. Chest CT shows multiple cavitary lesions. What is the most appropriate next step?

A) Continue adalimumab and add broad-spectrum antibiotics
B) Hold adalimumab, start empiric TB treatment (RIPE therapy)
C) Hold adalimumab, bronchoscopy for diagnosis only
D) Switch from adalimumab to rituximab

Answer: B. The clinical presentation is highly concerning for tuberculosis (cavitary lesions, subacute course, TNF inhibitor exposure). Empiric treatment should be initiated immediately given high morbidity and mortality. Holding the TNF inhibitor is critical, though immune reconstitution may paradoxically worsen symptoms initially. Bronchoscopy can provide confirmation but should not delay treatment in a critically ill patient.

Question 2: A 45-year-old man with ulcerative colitis on vedolizumab develops worsening bloody diarrhea (12 bowel movements daily) despite escalated dosing. Colonoscopy shows deep ulcerations. CMV PCR from colonic biopsy is positive at 1,500 copies/mg tissue. What is the best management?

A) Discontinue vedolizumab, start IV ganciclovir
B) Continue vedolizumab, add oral valganciclovir
C) Treat CMV with antivirals, reassess colitis after completion
D) Urgent colectomy

Answer: C. This scenario illustrates the "CMV colitis versus refractory UC" dilemma. The moderate-level CMV viremia and severe symptoms favor CMV as a significant contributor. The optimal approach is to treat CMV with ganciclovir/valganciclovir for 2-3 weeks, then reassess. If colitis persists after CMV clearance, then intensify IBD therapy or consider surgery. Vedolizumab continuation during CMV treatment is debated; holding temporarily is reasonable in severe cases.

Question 3: A 62-year-old woman with psoriatic arthritis on tofacitinib 5 mg BID develops acute onset left leg swelling. Ultrasound confirms extensive DVT (popliteal to common femoral vein). She has no prior VTE history. What is the most appropriate long-term management?

A) Anticoagulate for 3 months, resume tofacitinib afterward
B) Anticoagulate indefinitely, resume tofacitinib with close monitoring
C) Anticoagulate for 6 months, permanently discontinue tofacitinib
D) IVC filter placement, continue tofacitinib

Answer: C. Tofacitinib-associated VTE represents a drug-specific, recurrent risk. Most experts recommend permanent discontinuation after a VTE event, switching to an alternative biologic class. While some might argue for indefinite anticoagulation + tofacitinib continuation, this exposes the patient to bleeding risk and doesn't address the underlying prothrombotic drug effect. Three months is insufficient given the ongoing drug exposure. The correct answer reflects the current consensus approach following ORAL Surveillance data.

For Further Reading:

American College of Rheumatology Guidelines on Screening for and Prophylaxis of Tuberculosis Prior to Biologic Use
FDA Drug Safety Communications regarding JAK inhibitor safety warnings
European League Against Rheumatism (EULAR) recommendations for vaccination in patients on immunosuppressive therapies
Infectious Diseases Society of America guidelines on opportunistic infections in immunocompromised hosts

Tuesday, October 7, 2025

The Uncontrolled Seizure: Navigating Status Epilepticus and its Mimics

The Uncontrolled Seizure: Navigating Status Epilepticus and its Mimics

Abstract

Introduction

Beyond Benzodiazepines: The Evidence for Fosphenytoin, Valproate, and Lacosamide

The Second-Line Dilemma

The ESETT Trial: Equipoise Established

Fosphenytoin: The Traditional Workhorse

Valproate: Broad-Spectrum Efficacy

Levetiracetam: The New Favorite

Lacosamide: The Emerging Alternative

Practical Algorithm for Second-Line Therapy

Refractory & Super-Refractory Status Epilepticus: Anesthetic Doses and the ICU Pipeline

Defining the Beast

Anesthetic Agents: The ICU Armamentarium

Midazolam: First Among Equals?

Propofol: The Neurocritical Care Standard

Pentobarbital: The Heavy Artillery

Ketamine: The Mechanistically Distinct Option

Volatile Anesthetics: The Unconventional Rescue

EEG Targets: How Deep is Deep Enough?

The Weaning Protocol: Avoiding Yo-Yo Status

Adjunctive and Rescue Therapies for SRSE

Magnesium Sulfate

Hypothermia

Immunotherapy

Electroconvulsive Therapy (ECT)

Ketogenic Diet

Cannabidiol (CBD)

The SRSE Pipeline: When Do We Stop?

NCSE (Non-Convulsive Status Epilepticus): Who Needs an Urgent EEG?

The Invisible Epidemic

Clinical Presentations: A Spectrum

Who Needs an Urgent EEG? The Clinical Predictors

The "2HELPS2B Score": A Practical Tool

EEG Findings in NCSE: More Than Just Seizures

The IV Benzodiazepine Trial: A Diagnostic and Therapeutic Maneuver

Treatment of NCSE: Is Aggressive Always Better?

The Imitators of Status: Psychogenic Non-Epileptic Seizures (PNES) and Post-Anoxic Myoclonus

Psychogenic Non-Epileptic Seizures (PNES): The Great Masquerader

Clinical Red Flags for PNES

Laboratory and EEG Findings

The Diagnostic Conversation: Breaking the News

Management of Presumed PNES in the ICU

Post-Anoxic Myoclonus: Lance-Adams Syndrome and Acute Myoclonic Status

Acute Post-Anoxic Myoclonus (Within 24-48 Hours)

Lance-Adams Syndrome: Chronic Post-Anoxic Action Myoclonus

Autoimmune Encephalitis as a Cause of New-Onset Refractory Status Epilepticus

The Paradigm Shift: NORSE and FIRES

Epidemiology and Etiology

Clinical Red Flags for Autoimmune Etiology

Diagnostic Workup for Autoimmune Encephalitis

Immunotherapy: The Cornerstone of Treatment

First-Line Immunotherapy

Second-Line Immunotherapy

Tumor Screening and Removal

Prognosis and Long-Term Outcomes

The Ketogenic Diet in FIRES

Putting It All Together: The ICU Approach to Uncontrolled Seizures

The Time-Based Algorithm

The Diagnostic Workup Checklist

Clinical Pearls: The Top 10 for the Intensivist

Conclusion

References

Suggested Further Reading

Textbooks and Comprehensive Reviews

Key Clinical Trials

Online Resources

Key Clinical Pearls Summary Box

Assessment Pearls

Treatment Pearls

Diagnostic Pearls

Safety Pearls

Oyster (Pitfalls) Summary Box

Diagnostic Oysters

Treatment Oysters

Prognostic Oysters

Author's Clinical Hacks: Practical Tips for the Bedside

Medication Hacks