Efficacy of Pyridoxine in Early-Onset Idiopathic Intractable Seizures in Children

Abstract

To identify pyridoxine responsive seizures among children with early onset intractable seizures, and to identify pyridoxine-dependency as a subset in this group. Patients with neonatal onset idiopathic, intractable seizures were identified over a 6-month period and subjected to a 'pyridoxine trial', at the Pediatric Neurology Clinic of a tertiary-care teaching hospital in New Delhi, India. This consisted of an intravenous infusion of 100 mg of pyridoxine over 10-min with a simultaneous EEG monitoring. This procedure was carried out in the EEG laboratory with all appropriate precautions (including availability of resuscitation equipment and trained personnel). Continuous EEG monitoring was done throughout the infusion and till 20 min later, to look for correction of EEG abnormalities. All patients were then prescribed oral pyridoxine, 10-15 mg/kg/day divided TDS for 6 weeks, in addition to their current anticonvulsant therapy. Patients were reviewed every 15 days regarding compliance and change in seizure frequency. A reduction in seizure frequency by 50% of the baseline was considered as 'response' (significant change), meriting further continuation of pyridoxine therapy. In patients who remained seizure free on pyridoxine therapy, previous anti-epileptics were gradually tapered one by one. 621 children with active epilepsy were seen at the PNC, of which 48 had early-onset, medical intractable epilepsy, and 21 children (13 males and 8 females), aged between 11 month and 38 month were enrolled. The median age at onset of seizure was 5.1 months. The major seizure type was focal in 3 and generalized in 18 (including infantile spasm in 11). No patient had normalization of EEG during the 'trial'. Two patients (9.5%) had a response during the 2 weeks of oral treatment and oral therapy was continued. No toxicity or side-effects of pyridoxine were observed in these two patients over a follow-up of more than 18 months. Pyridoxine responsive seizures contribute a significant proportion to early-onset idiopathic intractable epilepsy in childhood. Routine use of pyridoxine in the management of early onset resistant seizures would go a long way in identifying these patients early.