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Seizures - status epilepticus

Red flags

>5 minutes of continuous seizure, or >=2 seizures without full recovery between - the operational definition; treat as status, do not wait for the classical 30-minute definition
Hypoxia, aspiration, hyperthermia, rhabdomyolysis - the systemic threats that kill, not the seizure itself
Failure to respond to first-line benzodiazepine - escalate on the clock, not on hope
Unexplained status in a known epileptic - always check for a reversible precipitant (non-adherence, infection, metabolic)
New-onset status in an adult - high index for structural, metabolic, toxic, or autoimmune cause

Differential by mechanism

Precipitants

Antiepileptic non-adherence/withdrawal - commonest cause in known epileptics
Structural - stroke (ischaemic/haemorrhagic), tumour, trauma, prior lesion
Metabolic - hypoglycaemia, hyponatraemia, hypocalcaemia, hepatic/uraemic encephalopathy
Infective - encephalitis, meningitis
Toxic - alcohol withdrawal, sympathomimetics, tricyclic overdose, isoniazid
Autoimmune/paraneoplastic encephalitis - consider if refractory with no other cause

Mimics

Psychogenic non-epileptic seizures (prolonged, side-to-side head movement, pelvic thrusting, eyes closed/resisting opening, normal post-ictal state)
Cardiac syncope with convulsive movements
Movement disorder/dystonic storm

Focused history

Known epilepsy - medication adherence, recent changes, last seizure
Witnessed onset and evolution, duration
Alcohol/substance use and withdrawal timing
Fever, infective symptoms, recent illness
Head trauma, prior stroke, malignancy
Collateral history critical - patient cannot give one during/immediately after

Focused examination

Airway, breathing, circulation first - status is a resuscitation scenario
Temperature (hyperthermia from ongoing convulsion), glucose (bedside, immediate)
Signs of trauma, tongue biting, incontinence (supports epileptic vs psychogenic)
Focal neurological signs once seizure controlled (Todd's paresis vs new structural lesion)
Signs of infection, meningism, rash
Signs of alcohol withdrawal or toxidrome

Investigation strategy

Bedside glucose immediately - treat hypoglycaemia before/alongside anticonvulsants
Bloods: UEC, calcium, magnesium, LFT, FBE, anticonvulsant levels, VBG/lactate, troponin if prolonged
CT brain - most patients, especially new-onset or focal signs
EEG - mandatory if not rapidly waking after apparent cessation, to exclude ongoing non-convulsive status
LP (once safe) if infective/autoimmune encephalitis suspected
Toxicology screen if indicated

Management

Time-based algorithm - do not deviate from the clock

0-5 min: ABC, oxygen, glucose, IV access, bloods

5-20 min (first-line): benzodiazepine

IV lorazepam 0.1mg/kg (preferred - longer anti-seizure effect than diazepam), or IM midazolam if no IV access (as effective as IV lorazepam - RAMPART trial), or IV diazepam
Repeat once at 5-10 min if seizure continues - do not exceed 2 doses before escalating

20-40 min (second-line): IV antiepileptic

Levetiracetam, sodium valproate, or fosphenytoin - ESETT trial showed equivalent efficacy (~45-50% seizure cessation) between all three
Choice by context: levetiracetam favoured for speed/safety profile and no need for cardiac monitoring; avoid valproate in known/suspected pregnancy or hepatic disease; fosphenytoin needs cardiac monitoring (bradycardia, hypotension)

40+ min (refractory status): general anaesthesia

ICU admission, intubation, continuous EEG monitoring
Propofol, midazolam infusion, or thiopentone - titrated to seizure/burst-suppression on EEG

Concurrent measures

Thiamine before/with glucose if alcohol use or malnutrition possible (avoid precipitating Wernicke)
Correct identified metabolic precipitant
Treat suspected infective/autoimmune cause empirically while awaiting results (e.g. empirical aciclovir if encephalitis cannot be excluded)

Traps

Under-dosing the first benzodiazepine dose - real-world dosing is frequently below guideline recommendation and predicts treatment failure
Waiting the "classical" 30 minutes before treating - the 5-minute operational threshold exists precisely to prevent this delay
Missing ongoing non-convulsive status after convulsions appear to stop - EEG is mandatory if consciousness does not rapidly normalise
Giving glucose without thiamine first in a malnourished/alcohol-dependent patient
Failing to search for and treat the underlying precipitant while focused on the seizure itself

Talk track

Status is >5 minutes continuous or recurrent seizures without recovery - treat on that clock. Benzodiazepine first (IV lorazepam or IM midazolam, one repeat), then a second-line IV agent at 20 minutes (levetiracetam, valproate, or fosphenytoin - ESETT showed equivalence), then general anaesthesia with continuous EEG if still refractory at 40 minutes. In parallel: glucose and thiamine, find and treat the precipitant, and get an EEG if consciousness does not normalise once convulsions stop.

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