Corneal xerosis and Keratomalacia occur due to the deficiency of?

UPRVUNL - 2021

Biochemistry & Nutrition

Easy

Appeared in: UPRVUNL - 2021

Explanation

Corneal xerosis and keratomalacia are advanced, severe ocular manifestations of Vitamin A deficiency, part of a condition called xerophthalmia.
Vitamin A is essential for maintaining the integrity of epithelial tissues; its deficiency leads to keratinization (drying and hardening) of the cornea, known as corneal xerosis.
Keratomalacia represents the most severe stage, where the cornea undergoes liquefaction (softening and melting), which can rapidly lead to perforation and irreversible blindness.
These conditions are considered a medical emergency requiring immediate high-dose Vitamin A supplementation to prevent vision loss.

Option A: Deficiencies in various B vitamins cause conditions like beriberi (thiamine-B1), pellagra (niacin-B3), and pernicious anemia (cobalamin-B12), which affect the nervous system, skin, and blood cells, not the structural integrity of the cornea.
Option B: Vitamin K is crucial for the synthesis of clotting factors in the liver. Its deficiency leads to impaired blood coagulation, resulting in easy bruising, bleeding, and hemorrhage.
Option D: Vitamin C (ascorbic acid) deficiency causes scurvy, which is characterized by defective collagen synthesis. This manifests as bleeding gums, poor wound healing, and corkscrew hairs.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Ocular manifestations of Vitamin A deficiency as background academic context rather than a clinical decision trigger.
Keratomalacia is a medical emergency. Nurses must recognize the signs and ensure immediate administration of high-dose Vitamin A as per protocol to prevent permanent blindness, especially in children.
Nurses play a vital role in prevention through patient and community education on diets rich in Vitamin A, such as dark green leafy vegetables, carrots, pumpkins, mangoes, papayas, eggs, and liver.
In India, Vitamin A deficiency is a major cause of preventable childhood blindness, addressed by a national program of prophylactic high-dose Vitamin A supplementation for children under 5.

How to Approach the Question

First, identify the key terms in the question: 'Corneal xerosis' and 'Keratomalacia'. Recognize these as severe eye conditions.
Connect these pathological terms to a nutritional deficiency. The question explicitly asks for the deficient vitamin.
Systematically review the primary functions of each vitamin listed in the options.
Recall that Vitamin A is fundamentally linked to vision (rhodopsin cycle) and the health of epithelial surfaces.
Recall that Vitamin B complex is mainly for energy metabolism and nerve function, Vitamin K is for blood clotting, and Vitamin C is for collagen synthesis and immunity.
Based on this, deduce that the severe epithelial and corneal damage described (xerosis and malacia) is a direct consequence of Vitamin A deficiency.

Concept Tested & Keywords

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E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 121-123

E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) p. 150-152