Idiopathic first seizure in adult life: who should be treated?

OBJECTIVE

To assess the accuracy of the diagnosis, recurrence rate, and fate after the first recurrence in adult patients with an untreated idiopathic first seizure.

DESIGN

Hospital based follow up study.

SETTING

One university hospital and three general hospitals in The Netherlands.

PATIENTS

165 patients aged 15 years or more with a clinically presumed idiopathic seizure; diagnosis was based on a description of the episode according to prespecified diagnostic criteria.

MAIN OUTCOME MEASURES

Results of additional investigations and follow up regarding the accuracy of the diagnosis; first recurrence; and response to treatment after the first recurrence.

RESULTS

Computed tomography showed major abnormalities in 5.5% of the patients and follow up led to doubts about the initial clinical diagnosis in another 6%. Cumulative risk of recurrence was 40% at two years. The cumulative risk of recurrence at two years was 81% (95% confidence interval 66% to 97%) in patients with epileptic discharges on a standard or partial sleep deprivation electroencephalogram, 39% (27% to 51%) in patients with other electroencephalographic abnormalities, and 12% (3% to 21%) in patients with normal electroencephalograms. Treatment was initiated in most patients who had one or more recurrences; 40 (70%) patients were completely controlled, eight (14%) had sporadic seizures, and nine (16%) did not become free of seizures within one year despite treatment.

CONCLUSIONS

The decision to initiate or delay treatment should be based on electroencephalographic findings.