Status Epilepticus

A single seizure lasting >5 minutes, or recurrent seizures without full recovery of consciousness between episodes; the 5-minute threshold (rather than the traditional 30 minutes) reflects evidence that seizures rarely self-terminate after this point and that earlier treatment improves outcomes.

Medical emergency with significant morbidity/mortality risk from the seizure itself and the underlying cause.

Classified by:

• Convulsive status epilepticus: generalized tonic-clonic activity ; most dangerous, highest mortality

• Non-convulsive status epilepticus: altered consciousness/behavior without prominent motor activity, diagnosed via EEG; often underrecognized

• Refractory status epilepticus: persists despite adequate doses of benzodiazepine + one second-line AED

• Super-refractory status epilepticus: continues/recurs ≥24 hours after anesthetic therapy initiation

• Ongoing generalized tonic-clonic movements, or repeated seizures without inter-ictal recovery of consciousness

• Progressive physiological derangement with prolonged seizure activity: hyperthermia, hypoxia, lactic acidosis, rhabdomyolysis, autonomic instability, cerebral edema risk

• Non-convulsive status: subtle motor signs (twitching, nystagmus), fluctuating consciousness, behavioral change, unexplained confusion ; high index of suspicion needed, especially post-convulsive seizure with failure to regain baseline consciousness

• Identify precipitant: known epilepsy with medication non-adherence/illness/sleep deprivation, new structural lesion, metabolic derangement (hypoglycemia, hyponatremia, hypocalcemia), CNS infection, alcohol withdrawal, drug toxicity/overdose, eclampsia, hypoxic brain injury

Clinical diagnosis based on observed seizure duration and pattern; treatment should NOT be delayed for investigations in convulsive status.

Immediate bedside tests (during/immediately after initiating treatment):

• Capillary glucose; mandatory, correct hypoglycemia immediately if present

• Vital signs, SpO2, temperature

Investigations (once treatment initiated, to identify cause):

• U&E, calcium, magnesium, LFTs, FBC

• AED levels if on known anticonvulsants

• Toxicology screen, alcohol level if relevant

• Blood cultures, lumbar puncture if infection suspected (CT head first if focal signs/raised ICP concern)

• CT head: if first presentation, focal neurological signs, head trauma, or failure to improve as expected

• EEG: for suspected non-convulsive status, or to confirm cessation of electrographic seizure activity in a paralyzed/sedated patient; clinical convulsions stop with paralytics but electrographic seizures can continue undetected

Differentials: psychogenic non-epileptic seizures, rigors, decerebrate/decorticate posturing, extreme agitation/dystonic reaction.

Time-based, stepwise protocol; treat aggressively and promptly, do not wait to "see if it stops".

0-5 minutes:

• ABC assessment, oxygen, IV access, glucose check (correct hypoglycemia: IV dextrose ± thiamine first if alcohol use disorder suspected), position to prevent injury/aspiration, note exact time of onset

5-10 minutes; first-line, benzodiazepine:

• IV lorazepam 4mg (adult), repeat once after 5-10 minutes if seizure continues (0.1mg/kg in children, max 4mg per dose)

• If no IV access: buccal midazolam 10mg, or rectal diazepam 10-20mg, or IM midazolam 10mg

10-30 minutes ; second-line, if still seizing after 2 benzodiazepine doses:

• IV levetiracetam 60mg/kg (max 4.5g) over 15 min, OR

• IV valproate 40mg/kg (max 3g) over 10 min (avoid in pregnancy/known hepatic disease), OR

• IV phenytoin 20mg/kg (max 2g) over 20-30 min with cardiac monitoring (hypotension, arrhythmia, purple glove syndrome risk) : fosphenytoin preferred where available

• Choice guided by patient factors rather than strict hierarchy (ESETT trial showed similar efficacy)

30-60 minutes ; refractory status, anesthesia required:

• Rapid sequence induction and intubation, general anesthesia: propofol, midazolam infusion, or thiopental ;ICU admission mandatory

• Continuous EEG monitoring essential once paralyzed/sedated; titrate anesthetic to seizure suppression or burst-suppression

• Continue/add maintenance AED alongside anesthesia

Super-refractory status (>24h despite anesthesia): consider ketamine infusion, inhalational anesthetics, immunotherapy if autoimmune encephalitis suspected, ketogenic diet; tertiary neurocritical care involvement essential.

Throughout: identify and treat underlying cause simultaneously, monitor for and manage complications (hyperthermia; active cooling, rhabdomyolysis ; aggressive IV fluids, aspiration pneumonia, cardiac arrhythmia).

Post-stabilization: establish/optimize maintenance AED therapy, address precipitant, EEG to confirm resolution, neurology follow-up, driving/safety counseling.