Thiamine deficiency is seen in all except
Homocysteinemia Thiamine was the first vitamin to be identified and is therefore called as vitamin Bl. Thiamine deficiency or beriberi refers to the lack of thiamine pyrophosphate, the active form of the vitamin . Thiamine pyrophosphate acts as a coenzyme in carbohydrate metabolism through the decarboxylation of alphaketoacids and in the formation of glucose by acting as a coenzyme for the transketolase in the pentose monophosphate pathway Causes of Thiamine deficiency Persons may become deficient in thiamine either by not ingesting enough vitamin B-1 through the diet or by excess use, which may occur in hypehyroidism, pregnancy, lactation, or fever (sates of high energy consumption, such as hypehyroidism, pregnancy, or severe illness, require more thiamine and other nutrients.) Prolonged diarrhea may impair the body's ability to absorb vitamin B-1, and severe liver disease impairs its use. Decreased absorption is seen in - Diarrhea - Chronic intestinal disease - Alcoholism - Malnutrition - Gastric bypass surgery - Malabsorption syndrome - Celiac and tropical sprue - Hyperemesis gravidarum - Long term starvation - Fad diets( Fad diets often do not contain necessary amounts of thiamine) Increased depletion is seen in - Diuretic therapies - Peritoneal dialysis - Hemodialysis(Dialysis robs thiamine from the circulation) Alcohol is known to interfere directly with the absorption of thiamine and with the synthesis of thiamine pyrophosphate.( thiamine should always be replenished when refeeding a patient with alcoholism, as carbohydrate repletion without adequate thiamine can precipitate acute thiamine deficiency.) Beriberi has been repoed among refugees who are relying on emergency food aids. This is due to the lack of available micronutrition supplementation Food faddism and fad diet are terms which refer to the tendency for idiosyncratic diets and eating patterns. A fad diet is supposed and promoted to improve health but may do nothing at all, or even have the opposite results if it is nutritionally unbalanced and unconfirmed by scientific studies Developing countries are known to have more vitamin deficiency problems in general Pathophysiology (Beriberi) In healthy individuals who are deprived of thiamine, thiamine stores are depleted in approximately 1 month. However, within a week of no thiamine intake, healthy people develop a resting tachycardia, weakness, and decreased deep tendon reflexes and some people develop a peripheral neuropathy. Nervous system involvement is termed dry beriberi. Dry beriberi involves both the peripheral and the central nervous systems. - Peripheral nerve involvement is typically a symmetric motor and sensory neuropathy with pain , parasthesias, and loss of reflexes. The legs are affected more than the arms. - Central nervous system involvement results in Wernicke-Korsakoff syndrome. - Wernicke's encephalopathy consists of nystagmus progressing to ophthalmoplegia, truncal ataxia, and confnsion. When there is additional loss of memory and a confabulatory psychosis, the syndrome is known as WernikeKorsakoff syndrome. Wet beriberi is the term used for the cardiovascular involvement of thiamine deficiency. Wet beriberi is characterized by marked peripheral vasodilation resulting in high-output hea .failure with dyspnea, tachycardia, cardiomegaly, and pulmonary and peripheral edema, with warm extremities mimicking cellulitis. Diagnosis In most instances, the clinical response to empiric thiamine therapy is used to suppo a diagnosis of thiamine deficiency. The most commonly used and widely available biochemical tests are measurement of erythrocyte transketolase activity and urinary thiamine excretion
Chronic diarrhoea
Chronic alcoholism
Homocystinemia
Food faddist