Status Epilepticus: Lecture Notes

Definition

Synonyms: overt, geneneralised tonic-clinic, major motor SE
Defined as a seizure lasting over 5 mins, or two or more seizures without recovery in between.

Aetiology (Adults)

Idiopathic (24-38%).
- If known epileptic, inadequate/ceased medication most common single cause.
Remote symptomatic (3-17%) – eg. prior CVA, head injury or cerebral palsy.
Progressive encephalopathy (5-15%) – eg. progressive neurological condition.
Acute symptomatic (40-57%):
- Hypoxia.
- Hypoglycaemia.
- Head trauma.
- Meningitis, encephalitis including HIV.
- Metabolic: hyponatraemia, hypocalcaemia, hyperthyroid, uraemia, eclampsia.
- Drug OD: alcohol, tricyclic antidepressants, theophylline, cocaine, amphetamine, anticholinergics, isoniazid.
- Drug withdrawal: alcohol, benzodiazepines, anticonvulsants, narcotics, cocaine.
- Cerebral tumour, CVA, vasculitis incl SLE.

Brown AFT, Wilkes GJ. Emergency department management of status epilepticus. Emerg Med 1994; 6:49-61.

Mortality

2.7% if seizure duration under one hour, up to 40% if seizure duration over one hour.
64% if SE secondary to anoxic brain injury, 32% if CNS infection.

Treatment

First line:

Prehospital: midazolam 0.15-0.3 mg/kg IM (or intranasally or buccal). Alternatively diazepam 0.5 mg/kg rectally.
Inhospital: midazolam 0.1-0.3 mg/kg, or diazepam 0.15 mg/kg, or clonazepam 0.5 -1 mg or lorazepam 0.1 mg/kg IV.
Follow with phenytoin 15-20 mg/kg IV diluted in saline at 50 mg/min with ECG monitoring and 0.22 micron filter. If available (not in Australia) give fosphenytoin 20 mg/kg equivalence IV at 150 mg/min, as does not contain propylene glycol so less incidence hypotension.

Second line:

Phenobarbitone 10-20 mg/kg IV at 100 mg/min (popular in paediatrics). Use in ECG monitored area only.

Third line:

Only in critical care area, with full monitoring ideally including EEG. No randomised trials comparing the different drugs.
More midazolam; or phenytoin to total 30 mg/kg.
Thiopentone – may require IPPV and vasopressor support.
Propofol 3-5 mg/kg, then infusion at 30-100 μg/kg/min; lignocaine or inhaled anaesthetic such as isoflurane etc.

Costello D, Cole A. Treatment of acute seizures and status epilepticus. J Intensive Care Med 2007;22:319-47. [Reference]

Management Problems

Failed drug therapy. Consider:
- Inadequate dosage, failure to initiate maintenance.
- Hypoxia, hypotension, metabolic derangement.
- Failure to identify underlying cause or subsequent complications.
- Pseudostatus (more common in known epileptics !).
Failure to regain consciousness. Consider:
- Medical consequences of SE: hypoxia, hypoglycaemia, cerebral oedema, hypotension, hyperpyrexia, iatrogenic.
- Progression of underlying disease process: head injury, meningitis, encephalitis, drug OD, brain anoxia.
- Subtle generalised convulsive SE; non-convulsive SE (EEG diagnosis).

Shearer P, Park D. Seizures and status epilepticus: Diagnosis and management in the emergency department. Emergency Medicine Practice. An Evidence-based Approach to Emergency Medicine 2006;8(8):1-32.
Walker M. Status epilepticus: An evidence-based guide. BMJ 2005;331:673-7. [Reference]
Marik P, Varon J. The management of status epilepticus. Chest 2004; 126:582-91. [Reference]
Bassin S, Smith T, Bleck T. Clinical review: Status epilepticus. Crit Care 2002; 6(2): 137-142 [Reference]