Which deficiency causes dilated cardiomyopathy with edema and is seen in alcoholism or malnutrition?

• A. Niacin deficiency
• B. Vitamin C deficiency
• C. Thiamine deficiency
• D. Vitamin B12 deficiency

Answer: (D)

Thiamine deficiency leads to wet beriberi, which presents with dilated cardiomyopathy and edema, especially in people with alcoholism or malnutrition. Thiamine (vitamin B1) is a crucial cofactor for enzymes that drive aerobic energy production, including pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase. Without enough thiamine, cardiac myocytes generate less ATP, causing systolic dysfunction and chamber dilation, while peripheral vasodilation and sodium retention contribute to edema. This cardiac involvement can be reversed with thiamine repletion when recognized early. In contrast, the other deficiencies cause different syndromes (pellagra with dermatitis/diarrhea/dementia for niacin; scurvy for vitamin C deficiency; megaloblastic anemia and neuropathy for vitamin B12) and do not classically present as dilated cardiomyopathy with edema.