Epilepsy and paroxysmal disorders: classification, antiseizure therapy, status epilepticus
Epilepsy questions test classification, drug choice by seizure type, and protocol-driven management of status epilepticus. Egypt's boards also probe pregnancy, driving, and the differentiation of epileptic from non-epileptic attacks.
Classification (ILAE framework)
Seizures are focal, generalised, or of unknown onset; focal seizures are further described by awareness (intact or impaired) and by motor versus non-motor features. Focal aware seizures previously called simple partial; impaired awareness corresponds to complex partial. Generalised types include absence, myoclonic, atonic, tonic-clonic. Focal seizures may evolve to bilateral tonic-clonic. Epilepsy syndromes matter: juvenile myoclonic epilepsy begins in adolescence with morning myoclonus, generalised tonic-clonic seizures, and 3-5 Hz spike-wave; childhood absence epilepsy has frequent brief absences with 3 Hz spike-wave.
Drug selection
Focal onset: levetiracetam, lamotrigine, carbamazepine, oxcarbazepine. Generalised: valproate is broad-spectrum but teratogenic (neural tube defects, reduced IQ, autism risk) and avoided in women of childbearing potential; lamotrigine and levetiracetam are preferred in pregnancy. Absence seizures respond to ethosuximide or valproate; carbamazepine and phenytoin worsen them and worsen myoclonus. Enzyme inducers (carbamazepine, phenytoin, phenobarbital) reduce oral contraceptive efficacy. Single seizures do not usually require long-term therapy after provocation is excluded.
Status epilepticus
At 0-5 minutes: airway, oxygen, glucose, IV access, time the seizure. At 5-20 minutes: a benzodiazepine - IV lorazepam 0.1 mg/kg (max 4 mg, repeat once) or IM midazolam 10 mg if no access. At 20-40 minutes: second-line IV agent - levetiracetam 60 mg/kg, valproate 40 mg/kg, or fosphenytoin 20 phenytoin equivalents/kg. Beyond 40 minutes: refractory status, anaesthetic doses of midazolam, propofol or thiopentone with continuous EEG. Non-convulsive status presents as confusion with ongoing electrographic seizures and requires EEG.
Worked example
A 30-year-old convulses for 8 minutes in the emergency department. Sequence: secure airway and check glucose; lorazepam 4 mg IV, repeat once at 4 minutes if ongoing; at 20 minutes levetiracetam 60 mg/kg IV; if still seizing at 40 minutes, intubate and start midazolam infusion with EEG monitoring; look for precipitants (infection, alcohol withdrawal, non-adherence, metabolic derangement).
Traps
Psychogenic non-epileptic seizures suggest themselves with eyes closed during the event, pelvic thrusting, fluctuating course, and no postictal confusion - but video-EEG is the arbiter. Do not label syncope with brief myoclonus as epilepsy. Never withdraw antiseizure medication abruptly, and remember that alcohol withdrawal seizures are treated with benzodiazepines rather than loading with enzyme-inducing drugs.