INCIDENCE OF PYRIDOXINE-DEPENDENT SEIZURES -A RETROSPECTIVE STUDY

Ebinger M., Schäfer K., Schultze Ch., Schaible Th., König St.

Children's Hospital Mannheim, University of Heidelberg, 68167

Mannheim, Germany

OBJECT: Pyridoxine dependent seizures (PDS) are a rarely diagnosed metabolic disorder inherited with an autosomal- recessive trait. To estimate the incidence of PDS in the district of our hospital, we performed a retrospective study over a course of 11 years. During that time we used a specific diagnostic and simultaneously therapeutic approach.

PATIENTS AND METHODS: Neonates displaying seizures are given first-line anti-epileptic drugs such as phenobarbital. Whenever the seizures are not controlled, a single shot of intravenous pyridoxine is applied. In case of PDS, the seizures immediately cease, but recur despite the continuing anticonvulsant medication after some days. If the seizures respond again to pyridoxine, we begin a permanent pyridoxine substitution and withdraw the anticonvulsant medication. The diagnosis of PDS is definite if the seizures do not recur. All mature neonates that were delivered to our hospital due to seizures or developed seizures during hospitalization were treated according to the described procedure. Excluded were preterm neonates.

RESULTS: After this regimen is administered, we found four children with PDS. The first trial of pyridoxine is started at 1, 5, and 6 days of age. Relating this incidence to the number of births in our hospital district yields a frequency of at least 1 in 20,000 of all newborn children.

CONCLUSIONS: The incidence of PDS may have been underestimated; PDS are likely to be under-recognized and therefore often mistreated. The high incidence of PDS we found in our hospital district shows that the applied, simple regimen is sufficient to diagnose PDS in neonates.