There has been considerable controversy about the appropriate management of a patient who has experienced an apparent first seizure. The decision to begin outpatient treatment with antiepileptics depends on the risk of recurrent seizures weighed against the risk/benefit ratio of anticonvulsant therapy. Until recently, reliable data on these questions have been unavailable. Previous studies have suggested rates of recurrence ranging from 23 to 71 percent. Some studies have found no benefit from treatment, while others have reported a 50 percent reduction in the risk of recurrence.
A careful analysis8 found that in patients with an apparent first seizure, the most important predictors of the risk of recurrence were the etiology of the seizure and the results of the EeG. In patients with idiopathic seizures and a normal neurologic exam, the risk of a recurrent seizure within two years was 24 percent if the EEG was normal and 48 percent if the EEG was abnormal. In patients with previous neurologic injury or illness or an abnormal neurologic exam, the risk was 48 percent if the EEG was normal, and 65 percent if the EEG was abnormal. Neither family history, age, sex, nor the presence of status epilepticus at the time of the first seizure was a strong predictor of the risk of recurrence. Unfortunately, EEG results are often not available to the emergency physician who must make a treatment decision.
A randomized multicenter clinical trial of 397 patients demonstrated that treatment of first unprovoked seizures appears to reduce the risk of recurrent seizures from 51 to 25 percent during two years of follow-up.9 Given these two studies, some general recommendations can be made. Patients with secondary seizures due to an identifiable neurologic condition should generally be treated, as their risk of recurrence is quite high (48 to 65 percent). In patients with idiopathic seizures, the decision is less clear. Their risk of recurrence may be as low as 24 percent if the EEG is normal. Given the expense, inconvenience, and potential side effects of treatment, some patients may wish to defer a decision about treatment until an EEG and neurologic consultation are obtained. In these patients, the only realistic approach is a full discussion of the risks and benefits of treatment. Often, a decision need not be made in the emergency department and patients can be referred to their regular physicians within one week for further evaluation and management.
The ideal antiepileptic regimen is a single-drug therapy that controls seizures with minimum toxicity. If treatment is initiated, drug selection is based on the type of seizure (Table224-6). For generalized tonic-clonic or focal seizures, either phenytoin or carbamazepine would be an appropriate choice for most adults (see above for loading information), both drugs are equally as efficacious and have similar side effect profiles. Valproate, phenobarbital, and primidone may also be used. For absence seizures, ethosuximide or valproate may be used (see Iable.224-5 for dosing). Gabapentin (900 mg to 1.8 g daily) and lamotrigine (300 to 500 mg daily) are newly approved drugs useful as adjunctive therapy.
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