Wet beriberi — DTM&H MCQ

Correct answer: A — Wet beriberi

The correct answer is A, wet beriberi, which results from thiamine (vitamin B1) deficiency and classically presents with high-output cardiac failure, bilateral oedema, breathlessness and cardiomegaly with preserved ejection fraction. The vignette's diet of polished white rice is the key clue, as milling removes the thiamine-rich husk and bran, and populations dependent on polished rice as a staple are at highest risk of this deficiency. Thiamine is essential for pyruvate dehydrogenase and the citric acid cycle; its deficiency causes peripheral vasodilation and a fall in vascular resistance, triggering renin-angiotensin-aldosterone activation, salt and water retention, and a high-output state rather than pump failure. This combination of geography, diet and preserved-EF high-output failure is pathognomonic for wet beriberi and responds dramatically to parenteral thiamine. Why the other options are wrong: B. Dilated cardiomyopathy: causes low-output failure with reduced EF and ventricular dilatation, not preserved EF high-output failure, and has no specific link to rice-based diets. C. Rheumatic heart disease: causes valvular lesions (commonly mitral stenosis or regurgitation) from prior streptococcal infection, producing valvular murmurs, not a nutritional high-output state. E. Peripartum cardiomyopathy: occurs in the peripartum period in women, which does not fit a 30-year-old male farmer, and typically causes reduced EF. D. Endomyocardial fibrosis: causes restrictive cardiomyopathy with endocardial fibrous thickening and diastolic dysfunction, seen in tropical Africa, not a diet-related high-output picture. Key point: High-output cardiac failure with preserved EF in someone whose staple diet is polished white rice indicates thiamine deficiency (wet beriberi), reversible with parenteral thiamine.

Reference: NCBI Bookshelf (StatPearls), Vitamin B1 (Thiamine) Deficiency, 2024, https://www.ncbi.nlm.nih.gov/books/NBK537204/