Wet beriberi — DTM&H MCQ

Correct answer: A — Thiamine deficiency causing wet beriberi

The correct answer is A, thiamine deficiency causing wet beriberi. A polished-rice diet strips the thiamine-rich husk, producing classic thiamine deficiency, and the combination of tachycardia, peripheral oedema and high-output cardiac failure is the textbook presentation of wet beriberi, driven by peripheral vasodilation and fluid retention when thiamine-dependent oxidative metabolism fails. Confusion appearing after a glucose-containing drink reflects the fact that carbohydrate load consumes remaining thiamine stores to run glycolysis and the Krebs cycle, precipitating or worsening Wernicke encephalopathy in a thiamine-deplete patient. UK guidance is explicit that thiamine must be given before or with any glucose load in at-risk malnourished or alcohol-dependent patients to avoid triggering this neurological deterioration. Why the other options are wrong: E. Vitamin A deficiency: causes xerophthalmia and night blindness, not cardiac failure or acute confusion after glucose. C. Iron deficiency causing cardiac failure: iron deficiency anaemia can cause high-output failure only at very severe haemoglobin levels and has no link to glucose-triggered confusion or a rice-based diet mechanism. D. Niacin deficiency causing pellagra: presents with dermatitis, diarrhoea and dementia (the three Ds), not oedematous high-output failure. B. Kwashiorkor alone: causes oedema from hypoalbuminaemia but does not explain tachycardia with high-output cardiac failure or acute glucose-precipitated confusion, and it is a protein-deficiency state distinct from thiamine deficiency. Key point: In malnourished patients, glucose must never be given before thiamine, because it can precipitate acute Wernicke encephalopathy on a background of wet beriberi.

Reference: Specialist Pharmacy Service (SPS), 'Using and prescribing thiamine in alcohol dependence' (based on NICE CG100), https://www.sps.nhs.uk/articles/using-and-prescribing-thiamine-in-alcohol-dependence/