Diagnostic evaluation: If the history suggests a seizure, an EEG should be obtained. Although the EEG will be normal in 50% of patients following a first seizure, an abnormal EEG provides useful information about seizure type and the likelihood of recurrence.2 In nearly a quarter of patients, the EEG will show epileptiform abnormalities that predict future seizures.2
Generally, an EEG should be obtained as soon as feasible, once a seizure is suspected. Some evidence in children suggests that EEG yield is higher in the 24 hours after a first seizure.
A noncontrast head CT or magnetic resonance imaging (MRI) reveals a significant abnormality about 10% of the time.2 A CT or MRI should be obtained. Few studies have compared CT to MRI in terms of yield in determining first seizure etiology, and those that do compare the two suffer from selection bias.2 Although CT or MRI are appropriate in evaluating a patient with a first seizure, the MRI’s greater resolution might provide a higher diagnostic yield in terms of seizure etiology, and, therefore, some experts recommend MRI over CT in nonemergent cases.2
Insufficient data exist to support or refute diagnostic testing beyond brain imaging and EEG. Although electrolyte abnormalities, hypoglycemia, and infections might infrequently cause seizures, such routine blood tests as complete blood count (CBC) and chemistry panels are rarely helpful.
As many as 15% of patients with a seizure will have minor abnormalities on routine lab tests, but the abnormalities do not appear to be the cause of the seizure.2
Lumbar puncture (LP) is categorically recommended only in patients in whom there is a clinical suspicion for infection as a seizure etiology. Reviews suggest that signs and symptoms of infection are typically present in patients with meningitis or another infectious cause for seizure; LP generally has limited utility in other noninfectious causes of seizure.2
The utility of toxicology testing in a first seizure has not been studied widely. Testing urine or blood for the presence of alcohol, cocaine, methamphetamines, benzodiazepines, or drug metabolites could be useful in the appropriate clinical setting.2
It is unclear whether a patient with a first seizure requires hospitalization. If initial testing in the ED rules out serious causes of seizures, the yield for hospitalization is likely to be low. In clinical practice, however, hospitalization is common and often necessary to complete such diagnostic testing as EEG and MRI.
Medical therapy: Patients with suspected epilepsy (e.g., those whose presenting seizure is, in retrospect, not their first seizure) should begin antiepileptic drug therapy (AED).1
Typically, a broad-spectrum AED—one that is effective against both partial and generalized seizures—should be used as initial therapy for epilepsy. These include valproate, lamotrigine, topiramate, zonisamide, and levetiracetam (see Table 1, above). Valproate has the longest history of effectiveness; levetiracetam has fewer drug interactions, and randomized trials support its efficacy.1
Checking blood electrolytes and liver enzymes is recommended before beginning AED treatment. Significant hepatic or renal dysfunction might necessitate dosing adjustments in many AEDs.2
Inpatient consultation with a neurologist might be helpful, although insufficient evidence exists that such consultation improves patient outcomes or makes care more cost-efficient. A neurologist should follow up on patients with a first seizure after hospital discharge.2
Patients with a first seizure that likely was provoked by a reversible condition (e.g., hypotension, hypoglycemia, infection) should generally not begin AED therapy. This also includes patients with multiple seizures in a brief period of time (less than 24 hours), all attributed to the same reversible cause.1