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Define status epilepticus. Describe its stepwise management.

Pharmacology · 2nd Professional — Para-Clinical

Definition

Status epilepticus is a seizure lasting more than 5 minutes, or two or more seizures without full recovery of consciousness between them. It is a medical emergency with a mortality of 10 to 20%.

The old definition of 30 minutes has been abandoned, because irreversible neuronal injury begins well before then and self-termination becomes unlikely after about 5 minutes — the change in definition was made to prompt earlier treatment
Precipitants — antiepileptic withdrawal or non-adherence (the commonest), alcohol withdrawal, infection (meningitis, encephalitis, cerebral malaria, neurocysticercosis), stroke, head injury, metabolic disturbance (hypoglycaemia, hyponatraemia, hypocalcaemia), drugs, eclampsia

Stepwise Management

Time	Action
0–5 minutes	ABC — airway, oxygen, position; check glucose immediately (give glucose with thiamine if low or unknown in an alcoholic); intravenous access; blood for electrolytes, calcium, drug levels, toxicology
5–20 minutes — first line	Benzodiazepine: intravenous lorazepam 4 mg (preferred — longer duration of anticonvulsant action and less redistribution than diazepam), or diazepam 10 mg, or intramuscular midazolam where there is no venous access. May be repeated once
20–40 minutes — second line	Intravenous phenytoin 20 mg/kg (or fosphenytoin), valproate 40 mg/kg, or levetiracetam 60 mg/kg — all comparable in trials
40–60 minutes — refractory	General anaesthesia with intubation and ventilation — midazolam infusion, propofol or thiopentone; continuous EEG monitoring
Throughout	Treat the cause — antibiotics for meningitis, antimalarials, correction of sodium or glucose, delivery in eclampsia (with magnesium sulphate)

CLINICAL PEARL

Lorazepam is preferred to diazepam although diazepam enters the brain faster. Diazepam is highly lipid-soluble, so it acts within seconds but redistributes out of the brain within about 20 minutes and the seizure returns. Lorazepam is less lipid-soluble, enters slightly more slowly, and stays in the brain for hours. In status, duration of effect matters more than speed of onset.

Practical Points on Individual Drugs

Phenytoin must be given slowly, no faster than 50 mg per minute, with cardiac monitoring — rapid infusion causes hypotension and arrhythmia, largely from the propylene glycol diluent
Phenytoin must never be mixed with glucose solutions, in which it precipitates; normal saline is used
Fosphenytoin is a water-soluble prodrug that can be given faster and is less irritant, and can be given intramuscularly
Extravasation of phenytoin causes severe tissue necrosis — the "purple glove" syndrome
Do not under-dose the benzodiazepine — giving too little for fear of respiratory depression is a common error and prolongs the seizure, which is itself far more dangerous

Applied Aspects

Always check the blood glucose — hypoglycaemia is a readily reversible cause and is missed if the seizure dominates attention
Consider eclampsia in any woman of childbearing age; magnesium sulphate, not a conventional antiepileptic, is the treatment, and delivery is definitive
In India, consider cerebral malaria, neurocysticercosis, tuberculous meningitis and hyponatraemia — the causes differ from those in Western texts and change management substantially
Non-adherence is the commonest precipitant in a known epileptic; ask about it, and address cost, supply and understanding rather than simply increasing the dose
Prolonged seizures cause hyperthermia, rhabdomyolysis, acidosis and aspiration, all of which require specific attention alongside stopping the seizure
Buccal or intranasal midazolam can be given by family members at home and prevents many hospital presentations; teaching the family is a practical, high-value intervention
Non-convulsive status must be considered in any patient who fails to wake after a seizure; it requires an EEG and is easily missed

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