Marasmus — DTM&H MCQ

Correct answer: D — Marasmus

The correct answer is D, Marasmus. Marasmus is the severe wasting form of severe acute malnutrition, characterised by profound loss of subcutaneous fat and muscle, giving the classic wizened, "old man" facies and visible ribs described in the stem, and it occurs in the setting of chronic energy and protein deficiency such as famine or drought. Crucially, marasmus is defined by the absence of bilateral pitting oedema, which distinguishes it from kwashiorkor. Appetite is typically preserved or only mildly reduced, and the child remains alert despite gross wasting, fitting the presentation given. WHO classifies both marasmus and kwashiorkor under severe acute malnutrition, diagnosed by very low weight-for-height, a MUAC under 115 mm, or the presence of oedema, but the wasted, non-oedematous phenotype specifically denotes marasmus. Why the other options are wrong: A. Kwashiorkor: This requires bilateral pitting pedal oedema as its defining feature, often with skin and hair changes and a relatively preserved fat appearance masked by oedema; the stem explicitly states no pedal oedema, excluding this diagnosis. B. Wet beriberi: Wet beriberi is thiamine deficiency causing high-output cardiac failure with oedema, dyspnoea and tachycardia, not the wasted, ribs-visible, appetite-reduced picture described here. E. Pellagra: Pellagra results from niacin deficiency and classically presents with dermatitis, diarrhoea and dementia, not global wasting with old-man facies. C. Scurvy: Scurvy is vitamin C deficiency causing gum bleeding, perifollicular haemorrhages and poor wound healing, none of which are described in this vignette. Key point: Severe wasting with visible ribs and an aged facial appearance but no bilateral pedal oedema defines marasmus, whereas oedema is the hallmark that separates kwashiorkor from it.

Reference: WHO Guideline on the prevention and management of wasting and nutritional oedema (acute malnutrition) in infants and children under 5 years, World Health Organization, 2023. https://www.who.int/publications/i/item/9789240082830