A first generalized seizure accounts for nearly 1% of all visits to the emergency department (ED).5 A patient who presents with a first seizure actually may have had seizures in the past that had not generalized or were not noticed, however.
The vast majority of new-onset seizures seen in the ED are due to factors that lower the seizure threshold, not epilepsy. This necessitates a thorough and immediate workup for the cause of the seizure. In one retrospective study6 of a 3-year period during which 247 patients were admitted for a first generalized seizure, the principal etiologies were:
The evaluation of a patient after a first known seizure should proceed as described for patients with known epilepsy, except that few tests are routinely omitted. (See Abnormal postictal labs)
Another test that is important to consider in these patients is the evaluation of the patient for pregnancy7 to determine limits on testing, such as computed tomography scanning. Pregnancy also may suggest the need to evaluate for hemorrhage or ischemia related to arteriovenous malformations, cavernous angiomata, or venous thrombosis, all of which are more likely to present in pregnancy.
A toxicology screen is indicated if there is a suspicion of drug abuse. Testing for human immunodeficiency virus (HIV) and syphilis should be considered, if suggested by the patient’s history.
If the patient is not actively seizing at the time of evaluation, obtain a clear history of the event, preferably in person and from a witness, so as to be able to distinguish the event from syncope, fainting, hyperventilation, psychogenic nonepileptic seizures, and other types of events that can mimic epileptic seizures. (See Nonepileptic seizures)
If the cause of the event cannot be clearly determined by the history, as is often the case, initial screening can help to determine whether the event was an acute symptomatic seizure or an idiopathic event. The focus of the initial evaluation is to look for acute medical conditions that could have precipitated the event. These include:
If such a condition is found, rapid admission to the hospital, evaluation, and treatment are indicated.
If the patient provides a good history, it is common in those who present with idiopathic seizures to find that multiple prior events have gone unreported.8 These events might be as subtle as brief episodes of morning myoclonus after sleep deprivation, occasional auras of déjà vu, a rising abdominal sensation, or unusual smells or tastes. The patient should be screened for epilepsy risk factors, such as:
Laboratory studies, including lumbar puncture if indicated, and a seizure-protocol MRI scan should be performed. If the patient rapidly returns to normal and the neurologic examination, screening blood work, and screening neuroimaging (e.g., CT scan) are normal, it is reasonable to discharge the patient from the emergency room without prescribing medication, provided that the patient can be seen promptly by a neurologist to complete the evaluation. In this setting, the patient should be told that, statistically, antiepileptic drugs reduce the risk of seizure recurrence by approximately 50% over 2 years, but nearly all patients experience at least some minor side effects.9–11 (See Approach to epilepsy)
If therapy with an antiepileptic drug is initiated, it should be chosen to treat the patient’s seizure type, or, if there is uncertainty, a broad-spectrum agent should be chosen. Such agents include:
If there is no clear family history of epilepsy and the patient presented with a generalized convulsive seizure, most ED physicians are still inclined to start therapy with phenytoin. This is an acceptable choice, since physicians are usually wise to use medications with which they feel comfortable. In many of these patients, this medication is eventually discontinued or replaced with another agent that may have fewer long-term side effects.
Reviewed and revised May 2004 by Steven C. Schachter, MD, epilepsy.com Editorial Board.
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