ABSTRACT

Pyridoxine dependent seizure (PDS) is an uncommon cause of intractable convulsions presenting in infancy and early childhood. Pyridoxinedependent seizures are characterized by intractable seizures that are not controlled with anticonvulsants but that respond both clinically and electrographically to large daily supplements of pyridoxine (vitamin B6). Here we present a case with a clinical response to pyridoxine after 3 days of treatment.

A three days old male newborn, born by uncomplicated normal spontaneous birth, was admitted to hospital with intractable myoclonic seizures started till birth. Physical examination revealed weak newborn reflexes and hypotonia. Routine biochemical investigation (serum electrolytes including calcium and magnesium, serum glucose, total blood count vb), cranial ultrasonography, serum quantitative aminoasid analysis, urine organic analysis and urine sulfite test were all revealed normal. EEG was found normal despite convulsions. Phenobarbital and pyridoxine (100 mg/d) were started. As the seizures were unresposive to treatment the patient was transfered to ICU where he was given midazolam. The seizures stopped the other day. Because the EEG was totally normal and the seizures did not respond to pyridoxine treatment, pyridoxine dependence was mostly excluded. No further seizures were seen and the patient was discharged from hospital at the 10th day after cessation of phenobarbital and pyridoxine treatment. After 15 days from the last seizure the patient was readmitted to hospital with status epilepticus. EEG was consistent with generalized burst-suppression pattern and phenytoin and midazolam treatment was commenced. As the seizures were resistant to any treatment, pyridoxine (100mg/day) was restarted. Both Glut1 defect and nonketotic hyperglycemia were excluded with further laboratory investigations. Seizures responded to pyridoxine therapy at the first day and the EEG returned to normal.

Keywords: Pyridoxine dependent seizure, infantile seizures, neonatal seizures, metabolic disorders