Although status epilepticus is defined as seizure activity that lasts for more than 30 minutes or that continues intermittently during this period without recovery of alertness, in practice, a treatment regimen should begin when a seizure lasts for more than a few minutes. The approach discussed here closely follows the recommendations of the Epilepsy Foundationís Working Group on Status Epilepticus, with a few exceptions.12,45,46 (See Table: Protocol for Treatment of SE)
The initial priority is given to the airway, breathing, and circulation. Oxygen is given by nasal cannula, and the patient is often placed on his or her side to minimize the chance of aspiration. Objects should not be placed in the patientís mouth. Within the first 5 minutes of a seizure, two reliable IV lines should be established. Venous blood is sent for electrolytes, glucose, and hematology studies and determination of AED levels. If there is any question of hypoglycemia, give 100 mg thiamine followed by 50 mL of 50% glucose by direct push into the IV line.
The pharmacologic approach to status epilepticus begins with treatment with a benzodiazepine, followed by phenytoin and then, if needed, barbiturates for refractory seizures. Lorazepam is preferred because of its longer duration of action, but diazepam is also an acceptable initial treatment. The initial dose can be 2 mg IV of lorazepam, repeated every 5 minutes up to a total dose of 0.1 mg/kg. If the status is stopped, phenytoin loading can then be used to prevent recurrent status.
Phenytoin often controls those seizures not effectively terminated by benzodiazepines. For most adults, the loading dose of 20 mg/kg is sufficient to produce blood levels of 10Ė15 mg/liter. If the initial dose of phenytoin is not effective, a second dose of 10 mg/kg can be given, which increases the blood level to approximately 25 mg/liter. Phenytoin must be given at a rate no faster than 50 mg per minute in adults, and cardiac monitoring should be used to watch for arrhythmias and hypotension.
Fosphenytoin, a phenytoin prodrug, is preferred when available, as it does not require a glycol diluent that renders phenytoin incompatible with glucose-containing solutions. This compound carries a much lower incidence of thrombophlebitis, can be given at a faster IV rate than phenytoin, and can be loaded intramuscularly when IV access is not available.
Seizures that are refractory to benzodiazepines and adequate doses of phenytoin can be treated with barbiturates. Adequate doses of barbiturates may lead to hypotension and respiratory depression, however, so dopamine should be present at the bedside when therapy with barbiturates is begun, and assisted ventilation should be readily accessible. Phenobarbital is given with an initial loading dose of 20 mg/kg at a rate of no more than 50 mg per minute.
EEG testing is required if the patient does not stop seizing. Continuous EEG is necessary to guide the degree of cerebral electrical suppression. Anesthetic doses of pentobarbital are initiated if the patient remains in status epilepticus (See Table: Pentobarbital-induced anesthesia in refractory generalized tonic-clonic status epilepticus). All patients are intubated before this step, if this has not been done before this time. (Separation of the effects of pentobarbital from the cardiorespiratory complications of refractory generalized tonic-clonic status epilepticus may be difficult.) A loading dose of pentobarbital is 10 mg/kg, which is followed by a continuous infusion at a rate of 0.5 to 4.0 mg/kg per hour. This infusion is titrated to maintain the EEG in a 3-to-1 burst-suppression pattern. (More recent evidence may suggest that titrating therapy to complete suppression of the EEG background may be more effective than titrating to burst suppression.47) When 12 to 24 hours have passed since suppression of epileptiform discharges, the amount of sedation can be lightened with EEG guidance. If seizures recur, a small bolus of pentobarbital is given to return the EEG to burst suppression or complete suppression, and the infusion is continued for another 48 to 60 hours. If seizures recur after this period, the prognosis for meaningful recovery is often poor, although many centers have pursued prolonged drug-induced coma, some for up to 50 days. Surviving patients have significant neurologic impairment.48
Many relatively small studies have tested medications other than pentobarbital for the treatment of refractory status epilepticus, including IV midazolam and propofol infusions.49 In general, these therapies may be useful in certain circumstances (particularly with children53), but their absolute indications have yet to be determined.
Bilateral motor activity with preserved consciousness is rare in epilepsy, with the exception of epileptic myoclonus and supplementary motor seizures. Motor signs may become subtle during prolonged seizures, as the neurons subserving motor function become fatigued and refractory to activation. Animal data suggest that 30 minutes of sustained seizure activity results in irreversible neuronal injury.44
Reviewed and revised May 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.
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