Diagnosing epilepsy in neurology clinics: a prospective study.

The certainty of the initial diagnosis of epilepsy was assessed prospectively by one neurologist in outpatients. One hundred and fifty-eight consecutive referrals with loss of consciousness or possible epilepsy were seen. The relative contributions to the initial diagnosis from the referral letter, history taking in clinic, physical examination, and investigation were compared. There was a referring diagnosis in 28.5%. The neurologist reached a diagnosis in 87% of the 158 cases: in 43% epilepsy, 25% syncope, 12% non-epileptic seizures and in 7% other diagnoses. There was a low correlation between referral and specialist diagnosis. Physical examination did not change the diagnosis in any patient. Investigations changed the diagnosis in one patient. Neuro-imaging revealed a relevant abnormality in 12/43 (27.9%) scanned. The yield from EEG was 7/25 (28%), but the EEG changed the diagnosis in only one case. Cardiac testing confirmed the type of syncope in 2/47 (4.3%) of patients. Blood tests did not contribute to the diagnosis in any patient. The neurology consultation significantly increased diagnostic certainty. The diagnosis of epilepsy remains largely clinical. It is important that patients are aware of this prior to investigation.