Seizures, Status Epilepticus, and ICU EEG
Definitions and treatment ladder
Convulsive status epilepticus begins at 5 minutes of continuous seizure activity; focal status with impaired awareness at 10 minutes. Treat with a benzodiazepine first (IM midazolam if no IV access), then a second-line agent: levetiracetam 60 mg/kg, fosphenytoin 20 phenytoin equivalents/kg, or valproate 40 mg/kg. Refractory status requires anesthetic doses of midazolam, propofol, or pentobarbital titrated to seizure cessation or burst suppression, typically for 24-48 hours, with continuous EEG and a slow taper.
EEG in the ICU
Obtain at least 20-30 minutes of EEG in any patient who fails to recover consciousness after a convulsion, and continuous monitoring in coma, after status, on ECMO, or during neuromuscular blockade. Recognize nonconvulsive status, lateralized and generalized periodic discharges, triphasic waves of metabolic encephalopathy, alpha coma, and burst suppression. Periodic discharges with clinical or EEG improvement after a benzodiazepine trial support an ictal-interictal continuum, but repeated sedation is not benign.
Trap: a paralyzed patient with continuous seizure activity shows only subtle eye or blood pressure changes; without EEG the diagnosis is missed.
Rule of thumb: a patient who remains unresponsive 20-30 minutes after a seizure, or whose exam cannot be explained by sedation, needs EEG before the explanation becomes postictal encephalopathy.