Unusual presentation of more common disease/injury Vitamin B12 deficiency: an unusual cause for recurrent generalised seizures with pancytopaenia

BACKGROUND Vitamin B12 deficiency is known to produce a variety of neuropsychiatric manifestations including peripheral neuropathy, subacute combined degeneration of the spinal cord, optic atrophy, dementia, psychosis and mood disturbances. This case highlights seizures as yet another complication of vitamin B12 deficiency. Although unusual, this condition is nevertheless completely reversible with appropriate therapy; thus awareness of this possibility can spare the occasional patient prolonged therapy with antiepileptic drugs. Moreover, certain commonly employed antiepileptic drugs are themselves known to lower vitamin B12 levels. Paradoxically, initiation of therapy with these drugs in a patient with underlying vitamin B12 deficiency can further exacerbate the problem, leading to poor control of seizures and unmasking other neurological and haematological manifestations of vitamin B12 deficiency. Vitamin B12 deficiency should be ruled out in all patients with otherwise unexplained seizures, especially when associated with suggestive features such as a macrocytic anaemia, as seen in our patient.