Chronic consumption of alcohol is the most common cause of thiamine deficiency. Thiamine is a vitamin critical for metabolism of glucose. Thiamine deficiency and direct toxic effects of alcohol on nerves result in peripheral neuropathy and lesions in the central nervous system, and thiamine administration is an essential part of management of alcoholic neuropathy. The doses of thiamine depend on the seriousness of the disease.
Thiamine
Thiamine is a cofactor for several regulating enzymes involved in glucose metabolism, including pyruvate dehydrogenase. Active pyruvate dehydrogenase converts an intermediate metabolite of glucose, pyruvate, to acetyl-coenzyme A. This molecule then enters a series of biochemical reactions, called Krebs cycle. This path is an efficient way of glucose conversion into a usable form of energy, which is a molecule called adenosine triphosphate. This molecule is then used in all biochemical reactions of your body. In the absence of thiamine, metabolism of glucose is steered toward less-efficient pathways where the end products include lactate. The decreased efficiency in energy generation, accumulation of various metabolites and increased levels of lactate are responsible for the neuronal damage. Severe lactate accumulation increases acidity of the blood, causing a life-threatening condition.
Peripheral Neuropathy
Your hands and feet are affected, which is often referred to as "glove-stocking distribution." The symptoms in the feet appear earlier than in the hands. You might feel that your hands and feet are burning. You also might lose the sense of position and the perception of vibration. As the neuropathy progresses, motoric nerves also are affected. This causes muscular weakness, difficulty walking and frequent falls.
Wernicke's Encephalopathy
Long-term alcohol abuse has serious impact on your brain. Acutely, this might present as a triad of symptoms called Wernicke's encephalopathy. The symptoms include ophtalmoplegia, ataxia and confusion. Ophtalmoplegia is paralysis of one or more of the eye muscles and causes changes in vision, including double vision. Ataxia is a loss of gross body movement coordination. At later stages, the patients also develop memory loss. The affected person covers the memory deficiency by telling stories that never happened. These confabulations were noted by Korsakoff, and thus are called Korsakoff amnestic syndrome.
Administration of Thiamine
According to "Medscape Reference", a patient with signs of peripheral neuropathy receives 5 to 30 mg of thiamine orally, three to four times per day for a duration of one month. Wernicke's encephalopathy is a medical emergency that requires hospitalization and intensive care. The recommended doses of thiamine are 100 mg given intravenously or intramuscularly, four times per day until the patient is able to resume normal diet.
References
- "Addiction biology"; Alcohol-thiamine interactions: an update on the pathogenesis of Wernicke encephalopathy; Todd KG, July 1999
- "Neurorology"; Painful alcoholic polyneuropathy with predominant small-fiber loss and normal thiamine status; Koike H; June 2001
- "Lancet Neurology"; Wernicke's encephalopathy: new clinical settings and recent advances in diagnosis and management; Sechi G; May 2007
- Medscape Reference: Thiamin
