A homeless man, who is a chronic alcoholic, is brought to the hospital in a wasted state. He is noted to have a peripheral neuropathy, difficulty balancing, and dementia. He dies suddenly of an arrhythmia, and at autopsy, lesions are found in the mamillary bodies and the vicinity of the third ventricle. The vitamin deficiency associated with these signs and symptoms is which of the following?

This man suffers from beri-beri (heart) and Wernicke-Korsakoff syndrome (brain). Thiamine deficiency in deteriorated alcoholics results in encephalopathy, peripheral neuropathy, and other disorders. Atrophy of the mammillary bodies, with loss of ganglion cells and rupture of small blood vessels, is characteristic. Deficiencies of the other vitamins are not related to these disorders.Diagnosis: Beri-beri, Wernicke encephalopathy