Status Epilepticus
Felicia C. Chu
Catherine A. Phillips
I. DEFINITIONS
A. Status epilepticus is defined as
1. One or more epileptic seizures lasting 30 minutes or longer without recovery between attacks (formal definition); or
2. Seizure activity lasting 5 minutes or longer (operational definition) without recovery between attacks.
B. Myoclonic status is repetitive, asynchronous myoclonic jerks typically in the setting of severe encephalopathy such as cerebral anoxia.
C. Simple partial status is continuous or repetitive focal seizures without loss of consciousness, such as focal motor seizures in epilepsia partialis continua.
D. Nonconvulsive status is a confusional state of 30 minutes or more.
1. Absence status: may have subtle myoclonic facial movements and automatisms of face and hands.
2. Complex partial status: either a series of complex partial seizures, separated by a confusional state, or a prolonged state of partial responsiveness and semipurposeful automatisms.
II. ETIOLOGY
A. Symptomatic status—status caused by a neurologic or metabolic insult—is more common than idiopathic status.
B. Status can be caused by stroke, anoxic brain injury, electrolyte disturbances (e.g., hyponatremia, hypomagnesemia, hypoglycemia, hyperglycemia, uremia, sepsis), drug or other toxicity, alcohol or other drug withdrawal, and decreasing antiepileptic medication.
C. Viral encephalitis from Epstein-Barr syndrome or herpes simplex virus can have an abrupt onset heralded by status epilepticus.
III. PROGNOSIS AND SEQUELAE
A. Overall, mortality rate is 7% to 25%. Advanced age, generalized tonic-clonic status epilepticus, depth of coma on presentation, and prolonged status (typically >24 hours) are poor prognostic factors.
B. Status caused by anoxia has the highest mortality rate followed by hemorrhage, tumor, metabolic disorders, and systemic infection. Status caused by alcohol withdrawal and antiepileptic drug discontinuation, and idiopathic status have lower mortality rates.
C. Long-term sequelae may include permanent focal neurologic deficits and chronic epilepsy. Aspiration pneumonia is a common complication of status.
IV. INITIAL ASSESSMENT, MANAGEMENT, AND MEDICAL STABILIZATION
A. Initial assessment and treatment should begin within 5 minutes of onset of seizure activity (Table 122-1).
B. History and exam: check for preexisting chronic seizure disorder, antiepileptic drug use, illicit drug use and trauma. Examine for focal neurologic abnormalities.
C. Status-induced hyperthermia will worsen neuronal injury and is essential to treat.
D. Metabolic acidosis often develops early in status and resolves spontaneously once seizures stop without treatment with bicarbonate.
E. When a metabolic disorder causes status, pharmacologic intervention alone is not effective.
F. Exclude systemic and central nervous system (CNS) infections; lumbar puncture (LP) is often necessary; leukocytosis, fever, and cerebrospinal fluid pleocytosis may be caused by status itself.
G. Only short-acting paralytic agents should be used; ongoing electroencephalogram (EEG) monitoring may be necessary for more continuous use.
H. Contrast-enhanced head computed tomography (CT) scan can be done after the patient has been stabilized and the seizures controlled. Magnetic resonance imaging (MRI) is preferred but often not practical in the emergent setting.
V. PHARMACOLOGIC MANAGEMENT OF GENERALIZED STATUS EPILEPTICUS
A. Goals: stop seizures early; prevent recurrence; try to determine the cause. Generalized convulsive status is a medical emergency.
B. A benzodiazepine drug is the initial therapy for status. Both diazepam and lorazepam have essentially the same cardiac (hypotension), respiratory (respiratory depression and apnea), and CNS-depressant side effects.
1. Lorazepam IV: 0.1 mg/kg at 2 mg/minute; a 2- to 4-mg dose may be given initially up to 0.2 mg/kg. The dose of diazepam is 0.15 mg/kg, additional 0.1 mg/kg if necessary.
2. Rectal diazepam is an alternative. For adults, 7.5 to 10 mg of the IV preparation or 0.2 mg/kg of the rectal gel preparation is administered per rectum (PR). The incidence of significant respiratory depression is lower with PR compared to IV administration.
3. Intramuscular (IM) absorption of these agents is delayed and incomplete; this route is unsuitable for treating status.
4. Midazolam IM can be effective if there is no IV access. For adults, 5 to 10 mg can be administered intramuscularly or rectally.
