Wernicke's encephalopathy is a degenerative brain disorder caused by the lack of thiamine (vitamin B1). It may result from alcohol abuse, dietary deficiencies, prolonged vomiting, eating disorders, or the effects of chemotherapy. Symptoms include mental confusion, vision impairment, stupor, coma, hypothermia, hypotension, and ataxia. Korsakoff's amnesic syndrome – a memory disorder – also results from a deficiency of thiamine, and is associated with alcoholism. The heart, vascular, and nervous system are involved. Symptoms include amnesia, confabulation, attention deficit, disorientation, and vision impairment. The main features of Korsakoff's amnesic syndrome are the impairments in acquiring new information or establishing new memories, and in retrieving previous memories. Although Wernicke's and Korsakoff's may appear to be two different disorders, they are generally considered to be different stages of the same disorder, which is called Wernicke-Korsakoff syndrome. Wernicke's encephalopathy represents the "acute" phase of the disorder, and Korsakoff's amnesic syndrome represents the "chronic" phase.
Treatment involves replacement of thiamine and providing proper nutrition and hydration. In some cases, drug therapy is also recommended.
Most symptoms can be reversed if detected and treated promptly. However, improvement in memory function is slow and, usually, incomplete. Without treatment, these disorders can be disabling and life-threatening.