Chapter 145. Seizures and Status Epilepticus in Adults

A seizure is an episode of abnormal neurologic function caused by inappropriate electrical discharge of brain neurons. Primary seizures are those without a clear cause. Secondary seizures result from another identifiable neurologic condition, such as a mass or stroke (Table 145-1).

Seizures are classified as generalized and partial. Generalized seizures are caused by nearly simultaneous activation of the entire cerebral cortex. The attacks begin with abrupt loss of consciousness. Generalized tonic-clonic seizures (grand mal) are the most familiar example. The patient suddenly becomes rigid, trunk and extremities are extended, and the patient falls to the ground. The rigid (tonic) phase is followed by a symmetric, rhythmic (clonic) jerking of the trunk and extremities, commonly associated with incontinence. After the attack, the patient is flaccid and unconscious. A typical episode lasts from 60 to 90 seconds, with gradual return of consciousness. Postictal confusion may persist for hours. Absence (petit mal) seizures are a subclass of generalized seizures. Typically seen in school-aged children, they usually last only a few seconds. Patients suddenly lose consciousness without losing postural tone. They appear confused, detached or withdrawn, and current activity ceases. The attack ends abruptly.

Partial seizures are due to electrical discharges beginning in a localized region of the cerebral cortex, often a brain lesion. The discharges may remain local or spread to other regions. Partial seizures may be simple, in which consciousness is not affected, or complex, in which consciousness is altered. Complex partial seizures are often due to discharges in the temporal lobe (also termed temporal lobe seizures). Symptoms include automatisms, visceral complaints, hallucinations, memory disturbances, distorted perception, and affective disorders.

Status epilepticus is continuous or intermittent seizures for more than 5 min without recovery of consciousness. Nonconvulsive status epilepticus is associated with minimal or imperceptible convulsive activity and is confirmed by EEG.

Eclampsia refers to the combination of seizures, hypertension, edema, and proteinuria in pregnant women beyond 20 weeks gestation or up to 3 weeks postpartum.

Obtain a detailed history, addressing the presence of preceding aura, abrupt or gradual onset, progression of motor activity, incontinence, whether the activity was local or generalized and symmetric or not, duration, and the presence of postictal confusion or lethargy. If the patient has a known seizure disorder, ascertain previous seizure pattern, common precipitants, and any change in antiepileptic regimen. If there is no previous history of seizures, a more detailed inquiry is needed. Ask the patient about recent or remote head injury. Persistent, severe, or sudden headache suggests intracranial pathology. Pregnancy or recent delivery raises the possibility of eclampsia. A history of metabolic or electrolyte abnormalities, hypoxia, systemic illness (especially cancer), coagulopathy or anticoagulation, drug ingestion or withdrawal, and alcohol use may pinpoint predisposing factors. Seizures are a common manifestation of central nervous system (CNS) disease in patients with the human immunodeficiency virus, although their causes differ somewhat from immunocompetent patients (Table 145-2).

Physical examination should include checking for injuries. Perform a directed neurologic exam and follow closely the level of consciousness. Progressive deterioration requires prompt intervention. A transient focal deficit following a simple or complex focal seizure is referred to as Todd paralysis and should resolve within 48 hours. If the patient's symptoms cannot be readily attributed to a benign cause, further urgent evaluation is warranted.

Laboratory testing should be individualized. In a patient with a known seizure disorder who has had a routine seizure, a glucose level and an anticonvulsant level may suffice. In an adult with a first seizure, more extensive studies are usually needed, including serum glucose, electrolytes, renal functions, calcium, magnesium, a pregnancy test, and toxicology studies. Lumbar puncture is indicated if the patient is febrile or immunocompromised, or if subarachnoid hemorrhage is suspected. Obtain a noncontrast head CT for the patient with a first seizure or a change in seizure pattern to identify a structural lesion or an acute intracranial process. A follow-up contrast CT or MRI may be indicated. Other radiographic testing will be case-specific.

The differential diagnosis of seizures includes syncope, pseudoseizures, hyperventilation syndrome, movement disorders, migraines, and narcolepsy.

1. Most commonly, little is required during the course of a seizure other than to protect the patient from injury. IV anticonvulsants are not indicated during an uncomplicated seizure.

2. In patients with a known seizure disorder whose anticonvulsant levels are low, supplemental doses may be appropriate. Oral loading of phenytoin (18 milligrams/kilogram PO as a single dose or divided into 3 doses given every 2 hours) will achieve therapeutic concentrations in 2 to 24 hours. Alternatively, 10 to 20 milligrams/kilogram of IV phenytoin at a rate of 25 milligrams/min achieves anticonvulsant effects in 1 to 2 hours. The dose of fosphenytoin is 10 to 20 milligrams phenytoin equivalent at a maximum IV rate of 150 milligrams/min. Loading doses of other antiepileptics may be guided by the patient's neurologist.

3. Administer magnesium sulfate, 4 to 6 grams IV, to eclamptic patients followed by an infusion of 1 to 2 grams/h. Consult an obstetrician early in the patient's care.

4. Patients in status epilepticus require large-bore IV access, cardiac monitoring, and pulse-oximetry. Endotracheal intubation is recommended. If a paralytic agent is used, a short-acting agent is preferred so seizure activity can be monitored. Lorazepam is considered the initial anticonvulsant of choice, followed by phenytoin or fosphenytoin (Figure 145-1). In refractory cases, consider IV valproate, phenobarbital, or pentobarbital. If seizures persist, induce anesthesia with IV infusions of midazolam or propofol. Neuromuscular blocking agents may be necessary, in which case EEG monitoring is mandatory.

Patients with a first seizure who have a normal neurologic examination, no acute or chronic medical comorbidities, normal diagnostic testing including neuroimaging, and a normal mental status can be discharged from the ED. Initiation of antiepileptic medication and further testing may be deferred to the outpatient setting. Consider admission for patients who do not meet the above criteria. Instruct discharged patients to take precautions to minimize the risks for injury from further seizures. Swimming, working with hazardous tools or machines, and working at heights should be prohibited. Driving is prohibited until cleared by the neurologist or primary care physician, and driving privileges should conform to state laws.