Infantile beriberi — DTM&H MCQ

Correct answer: B — Urgent thiamine replacement

The correct answer is B, urgent thiamine replacement. This infant has classic infantile (wet) beriberi: tachycardia, high-output heart failure and lactic acidosis in an exclusively breastfed baby whose mother has subsisted on polished rice, which is stripped of thiamine-rich husk. Thiamine pyrophosphate is an essential cofactor for pyruvate dehydrogenase and alpha-ketoglutarate dehydrogenase; deficiency blocks aerobic pyruvate metabolism, forcing anaerobic glycolysis and causing lactic acidosis while starving the myocardium of ATP, producing acute cardiac failure. Because maternal thiamine stores and breast milk thiamine content are both depleted, the infant becomes critically deficient within weeks. This is a medical emergency: parenteral thiamine given promptly is life-saving and clinical improvement can occur within hours, exactly as described in reports of thiamine-responsive infant Shoshin beriberi. Why the other options are wrong: E. High-dose vitamin A: treats xerophthalmia and reduces measles mortality but has no role in cardiac beriberi and will not correct the metabolic block causing acidosis. D. Oral iron alone: addresses iron-deficiency anaemia, not the acute cardiogenic and metabolic crisis of thiamine deficiency, and oral therapy is too slow even if relevant. A. Nicotinamide: corrects niacin deficiency (pellagra), which causes dermatitis, diarrhoea and dementia, not this acute cardiac and lactic acidosis picture. C. Zinc alone: used for diarrhoeal disease and growth faltering but does not reverse the enzymatic block in pyruvate metabolism responsible for this presentation. Key point: Acute heart failure with lactic acidosis in a breastfed infant of a thiamine-deplete, rice-dependent mother is infantile beriberi and demands emergency parenteral thiamine before other supportive measures.

Reference: Sobrino Diaz A et al, Shoshin beriberi and thiamine-responsive right heart failure in infants: recognition and emergency management protocol, ScienceDirect/Archives de Pediatrie, 2022, https://www.sciencedirect.com/science/article/abs/pii/S0929693X22002081