Misdiagnosis and treatment in juvenile myoclonic epilepsy.

Of 1300 epileptic patients 76 (5.8%) were found to have juvenile myoclonic epilepsy (JME). These 76 patients were examined at the epilepsy outpatient clinic of Bakirköy State Hospital for Neurological and Psychiatric Diseases between 1991 and 1996 and data obtained were analysed retrospectively. Clinically typical absence seizures were reported in 40.8%, myoclonic jerks in 100%, and generalized tonic-clonic seizures in 82.9% of the patients. Neurological and mental examination was normal for all patients with the exception of three cases; two with essential tremor and one with minimal dysarthria. Precipitating factors were noted in 85.5% of cases. Abnormal EEG was recorded in 73 (6.1%) patients. Abnormalities mainly consisted of generalized discharges of spike/polyspike and slow-wave (86.6%) and generalized paroxysmal theta or delta (9.2%). Fifteen (19.7%) had focal abnormalities and 20 (26.4%) had photoconvulsive discharges. Of the 76 patients, 40 (52.6%) were not diagnosed at the initial interview; definite diagnosis was delayed by a mean of 5.9 years. As a result of misdiagnosis at the initial interview 40 patients had been administered AED except for valproate. After reassessment of clinical and EEG findings, the medication was changed to valproate therapy. As a result, 65 of our JME patients (85.5%) were seizure free after a one-year follow-up period.