Prolonged consumption of alcohol can cause thiamine deficiency. Thiamine plays a role in energy metabolism and its absence damages peripheral nerves and certain areas in the brain. This is known as Wernicke-Korsakoff dementia. Some non-alcohol related conditions also cause the same disease.
The Role of Thiamine in Metabolism
Thiamine, a vitamin B-1, is a key co-factor of several enzymes that control metabolism of glucose. These enzymes convert six-carbon molecules of glucose into one-carbon molecules of CO2 and water. During this conversion, energy is released and stored in a form of adenosine tri-phosphate, or ATP. ATP then fuels all energy-requiring functions in your cells. The areas in brain with high dependency on thiamine are affected most. Dysfunctional cells in those areas of brain are responsible for neurological signs of the disease.
Wernicke-Korsakoff Dementia in Alcoholics
Alcohol decreases thiamine absorption and reduces the ability of liver to store the vitamin. The deficiency then causes peripheral neuropathy with burning feet and hands. As the deficiency worsens, the effects on the brain become apparent. Four symptoms are characteristic for Wernicke-Korsakoff dementia: First, patients may not be able to coordinate their movements. This is called ataxia. Second, they may have dual vision, or nystagmus, which is rhythmic involuntary oscillations of the eyes. Third, the patients may have altered mental status. Carl Wernicke described these three symptoms in 1881. Several years later, Sergei Korsakoff noted that alcoholic patients have memory loss and that they replace the forgotten moments with stories that never happened. This is called confabulations.
Other Forms of the Alcohol-Related Brain Damage
An article in the April 2011 issue of "Nature Reviews Neurology" reviews different forms of alcohol-related brain damage and relates them to anatomical and cellular findings obtained by modern methodology. This research area is important for understanding how alcohol causes brain damage and whether there is a clinical sign or a laboratory marker that help in diagnosis of the conditions at earlier stages.
Non-Alcohol Related Wernicke-Korsakoff
Another area of research targets Wernicke-Korsakoff dementia that did not develop due to alcohol consumption. For example, cancer patients may also have Wernicke-Korsakoff dementia due to malnourishment associated with cancer, as noted in a case study in the November 2009 issue of "Oncology."
Reversibility of the Dementia
Wernicke-Korsakoff dementia is a medical emergency that can have grave consequences. Thiamine deficiency is a clear cause of the disease. Timely administration of high-dose thiamine may reverse some, but usually not all, of the damage.
References
- "medEssentails for the USMLE Step 1"; Michael S Manley, MD; 2010
- "Annals of Emergency Medicine"; Myths and misconceptions of Wernicke's encephalopathy: what every emergency physician should know. Donnino MW; December 2007
- "Nature Revue Neurology"; Clinical and pathological features of alcohol-related brain damage; Zahr NM, April 2011
- "Oncology"; Wernicke's encephalopathy: an underrecognized and reversible cause of confusional state in cancer patients; Kuo SH et al.; November 2009
- Alzheimer's Association; Wernicke-Korsakoff Syndrome; Nov. 17, 2010
