Serum vitamin B12 deficiency and hyperhomocystinemia: a reversible cause of acute chorea, cerebellar ataxia in an adult with cerebral ischemia.

Patients with vitamin B12 deficiency have protean neurological manifestations that are often insidious. Acute onset of cerebellar dysfunction and extrapyramidal manifestations like dystonia and chorea are rather uncommon in adults. We describe a patient who manifested with acute onset of language dysfunction, chorea and ataxia. There was no history of hypertension, diabetes or ischemic heart disease. He had low serum vitamin B12 and elevated serum homocystine levels. He improved dramatically following B12 replacement therapy. Our patient provides insight into the pathophysiological mechanism of this rare manifestation. Further the importance of considering vitamin B12 deficiency, in country like India, where vegetarian food practice is quite common, is being emphasized.