Infantile encephalopathy due to vitamin deficiency in industrial countries

Severe avitaminosis causing life-threatening conditions in the infantile age group is extremely uncommon and has been reported in babies with malabsorption receiving prolonged inadequate vitamin supplements. We report two infants who presented with neurological deterioration. Immediate work-up and treatment for infectious and inborn metabolic disorders were initiated and the diagnosis, made with a few days delay, was prolonged avitaminosis of thiamine (B1) and cobalamin (B12). B1 deficiency was suspected when further neurological deterioration was observed during administration of intravenous fluids containing glucose in an infant with high lactate levels in the cerebrospinal fluid. High transketolase activity that normalized after thiamine treatment and the findings in the MRI and MRS of the brain confirmed the suspected diagnosis. B12 deficiency was suspected in an infant of a strict vegetarian mother who presented with neurological deterioration and severe megaloblastic anemia. The diagnosis was confirmed when low serum levels of B12 and methylmalonic aciduria were detected and treatment with B12 resulted in normalization of urinary methymalonic acid. Avitaminosis, even in industrialized countries, should be considered in an atypical age group with no known risk factors. Early diagnosis and prompt treatment may accomplish a quick recovery with fewer sequelae.