Late-onset pyridoxine-dependent seizures: report of two cases.

We report two cases of late-onset pyridoxine-dependent seizures with age onset at 14 and 9 months, respectively. Their intractable seizures were refractory to diazepam, phenobarbital, phenytoin, carbamazepine, valproic acid, and adrenocorticotropic hormone, but stopped soon after intravenous administration of pyridoxine. The psychomotor development was retarded in both cases. Pyridoxine dependency is one of the few treatable intractable seizures in infancy. It should always be kept in mind, even in patients with intractable seizures beyond the neonatal period, regardless of previous patterns of electroencephalography and seizure types and responsiveness to the conventional anticonvulsants.