Vitamin A deficiency — DTM&H MCQ

Correct answer: D — Vitamin A deficiency

The correct answer is D, Vitamin A deficiency. Night blindness together with dry, foamy conjunctival plaques (Bitot's spots) is the classic clinical picture of xerophthalmia due to vitamin A deficiency, and measles itself depletes hepatic vitamin A stores and increases metabolic demand, precipitating or worsening deficiency in already malnourished children such as those in refugee camp settings. This combination (measles plus night blindness plus Bitot's spots) is a WHO-recognised indication for urgent high-dose vitamin A treatment to prevent progression to corneal ulceration, keratomalacia and permanent blindness, and to reduce measles-associated morbidity and mortality. The keratinised, foamy conjunctival lesion is pathognomonic for vitamin A deficiency and is not produced by any of the other listed conditions. Why the other options are wrong: B. Riboflavin deficiency: causes angular stomatitis, glossitis and corneal vascularisation, not night blindness or Bitot's spots, so it does not fit the eye findings described. E. Onchocerciasis: causes chronic itching, skin nodules and progressive visual loss (river blindness) from microfilarial keratitis and chorioretinitis, transmitted by Simulium blackflies, not an acute association with measles or foamy conjunctival plaques. C. Trachoma: caused by Chlamydia trachomatis, produces follicular conjunctivitis, conjunctival scarring and trichiasis leading to corneal damage from repeated infection, not night blindness or Bitot's spots. A. Acanthamoeba keratitis: a painful contact-lens-associated corneal infection with ring infiltrate, irrelevant to this child's context and unrelated to measles or vitamin A status. Key point: night blindness plus Bitot's spots in a malnourished child, especially with measles, is xerophthalmia from vitamin A deficiency and mandates immediate high-dose vitamin A treatment.

Reference: World Health Organization: Vitamin A supplementation (immunization/micronutrient linkage guidance) and WHO/UNICEF joint statement on vitamin A for measles management; WHO, https://www.who.int/teams/immunization-vaccines-and-biologicals/essential-programme-on-immunization/integration/linking-with-other-health-interventions/vitamin-a