What causes Wernicke-Korsakoff syndrome?
Wernicke-Korsakoff syndrome is actually a spectrum, including two separate sets of symptoms, one of which tends to start when the other subsides. Wernicke's encephalopathy involves damage to multiple nerves in both the central nervous system (brain and spinal cord) and the peripheral nervous system (the rest of the body). It may also include symptoms
caused by alcohol withdrawal. The cause is generally attributed to malnutrition, especially lack of vitamin B1 (thiamine), which commonly accompanies habitual alcohol use or alcoholism.
Wernicke-Korsakoff syndrome is caused by a deficiency in the B vitamin thiamine. Thiamine plays a role in metabolizing glucose to produce energy for the brain. An absence of thiamine therefore results in an inadequate supply of energy to the brain, particularly the hypothalmus (which regulates body temperature, growth and appetite and has a role in emotional response. It also controls pituitary functions including metabolism and hormones) and mammillary bodies (where neural pathways connect various parts of the brain involved in memory functions). The disease is typically associated with chronic alcoholism, but may be associated with malnutrition or other conditions which cause nutritional deficiencies.
Heavy alcohol use interferes with the metabolism of thiamine, so even in the unusual cases where alcoholics are eating a balanced diet while drinking heavily, the metabolic problem persists because most of the thiamine is not absorbed.
Korsakoff syndrome, or Korsakoff psychosis, tends to develop as Wernicke's symptoms diminish. It involves impairment of memory out of proportion to problems with other cognitive functions.
Patients often attempt to hide their poor memory by confabulating. The patient will create detailed, believable stories about experiences or situations to cover gaps in memory. This is not usually a deliberate attempt to deceive because the patient often believes what he is saying to be true. It can occur whether or not the thiamine deficiency was related to alcoholism and with other types of brain damage. Korsakoff psychosis involves damage to areas of the brain involved with memory.