Epileptic seizures in 1902 patients: a perspective from a consultant neurological practice (1961-1991)

Over a 30 year period, a total of 1902 persons with at least one epileptic seizure was referred to a consultant neurological practice. The type of seizure that was present was not determined in 10.6%, was generalised in 33.3%, partial in 53.9%, infantile convulsions in 1.1%, and 'generalised-partial' in 1.2%. The latter category probably represented the coincidence of generalised seizures (overt or as an EEG trait) and partial seizures in occasional individuals. At presentation, 13.9% of the series had experienced only a solitary seizure (80% of these a tonic-clonic fit). Compared with the rest of the series, solitary seizure sufferers more often went at least 1 year seizure free (78.6% v. 40.2%, for those with known outcomes), and were known to have been able to cease therapy after 3-5 years without seizures (26.5% v. 12.5%). Established seizure disorders (first seizure more than 1 year earlier, at least three tonic-clonic fits and/or at least 10 less severe seizures) were already present at referral in 996 persons (52.4%). Of these persons, a minimum of 9.1% were able to cease therapy after 3-5 years seizure free. In the whole series, at least 274 persons (14.4%) ceased therapy after a mean of 4.72 +/- SD 3.05 years without seizures. The outcome was unknown in 50: seizures recurred in 20.5% of the remaining 224 who were followed for at least 1 year (in 70% the recurrence was within 1 year of withdrawing therapy). Even one tonic-clonic fit at any time increased the chance of a failed withdrawal of therapy, while seizure control with anticonvulsant monotherapy, earlier age at first seizure and earlier age at seizure control correlated with a successful withdrawal of therapy.