Epilepsy in vitamin B12 deficiency and its treatment in infancy

Vitamin B12 (cobalamin) deficiency in European infants is rare. Common symptoms include failure to thrive, neurodevelopmental delay or regression, microcephaly and apathy.

We report on two infants diagnosed with vitamin B12 deficiency who developed the above mentioned symptoms and new-onset seizures, the latter after initiation of vitamin B12 treatment.

In a 5 month old girl presenting with encephalopathic symptoms a vitamin B12 deficiency was diagnosed by methylmalonic aciduria and increased serum level of homocysteine. She was solely breast-fed and her mother suffered from an atrophic gastritis. Within the first 4 weeks after starting vitamin B12 replacement therapy our patient developed a hypsarrhythmia in the EEG without clinical seizures. Vigabatrin therapy was successful and in the subsequent EEGs there were no apparent epileptiform discharges after vigabatrin withdrawal. The girl shows appropriate neurodevelopment.

In a 14.5 month old boy with psychomotor retardation suffering from pneumonia the routine blood test revealed a megaloblastic anemia. Further investigations confirmed the diagnosis of vitamin B 12 deficiency. Denying supplementary alimentation he was only breast-fed. His mother was on a vegan diet. After 5 days of vitamin B12 intravenous-replacement the boy showed a tremor and jerks. EEG recording revealed a bifrontal status epilepticus which was not related to the jerks. Giving clonazepam intravenously several times and adding it temporarily to an oral anticonvulsive treatment consisting of phenobarbital and oxcarbazepine the EEG improved. After cessation of the anticonvulsive therapy, EEG recordings remain normal, but the boy still shows a slight developmental delay.

In evaluation of failure to thrive and developmental disturbance vitamin B12 deficiency should be taken into account. Epilepsy is a possible but not a leading symptom of vitamin B12 deficiency. In our cases an association between replacement therapy and the development of epilepsy can not be excluded. In management of vitamin B12 supplementary treatment this should be considered.