EPILEPTOLOGY OF THE FIRST-SEIZURE PRESENTATION - A CLINICAL, ELECTROENCEPHALOGRAPHIC, AND MAGNETIC-RESONANCE-IMAGING STUDY OF 300 CONSECUTIVE PATIENTS

Background Prognosis and treatment of the first seizure depends on ide ntification of a specific epilepsy syndrome, yet patients with first s eizures are generally regarded as a homogeneous group. We studied whet her it is possible to diagnose specific epilepsy syndromes promptly by use of standard clinical methods, electroencephalography (EEG) and ma gnetic resonance imaging (MRI). Methods 300 consecutive adults and chi ldren presented with unexplained seizures, We systematically collected clinical data from patients and witnesses. and attempted to obtain an EEG within 24 h of the seizure. Where the EEG was negative, a sleep-d eprived EEG was done. MRI was done electively. Findings A generalised or partial epilepsy syndrome was clinically diagnosed in 141 (47%) pat ients. Subsequent analysis showed that only three of these clinical di agnoses were incorrect, Addition of the EEG data enabled us to diagnos e an epilepsy syndrome in 232 (77%) patients. EEG within 24 h was more useful in diagnosis of epileptiform abnormalities than later EEG (51 vs 34%). Neuroimaging showed 38 epileptogenic lesions, including 17 tu mours. There were no lesions in patients for whom generalised epilepsy was confirmed by EEG. Our final diagnoses were: generalised epilepsy (23% of patients); partial epilepsy (58%); and unclassified (19%). Int erpretation An epilepsy syndrome can be diagnosed in most first-seizur e patients. Ideally, an EEG should be obtained within 24 h of the seiz ure followed by a sleep deprived EEG if necessary. MRI aids diagnosis and should be done for ail patients except for those with idiopathic g eneralised epilepsies and for children with benign rolandic epilepsy.