The first sign of Vitamin A deficiency is?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2018

Applied Nutrition & Dietetics

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2018

Explanation

Night blindness (nyctalopia) is the earliest functional symptom of Vitamin A deficiency.
Vitamin A, in the form of retinal, is a critical component of rhodopsin, the pigment in the retina's rod cells responsible for vision in low light.
A deficiency of Vitamin A impairs the regeneration of rhodopsin, leading to poor dark adaptation and difficulty seeing in dim light or at night.
This functional impairment occurs before any structural changes to the eye become visible.

Option A: Corneal ulceration is a sign of severe, late-stage Vitamin A deficiency (Stage X3A/B), known as keratomalacia. It is a medical emergency and can lead to permanent blindness.
Option B: Bitot's spots are a specific clinical sign of Vitamin A deficiency, but they are not the first sign. They typically appear after the onset of night blindness and conjunctival xerosis (Stage X1B).
Option D: 'Muddy eyes' is a non-specific and non-clinical term. While conjunctival xerosis (dryness) can cause the conjunctiva to appear dull or wrinkled, 'muddy eyes' is not a recognized diagnostic sign of Vitamin A deficiency.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Early signs of Vitamin A deficiency as background academic context rather than a clinical decision trigger.
Nurses play a key role in identifying early Vitamin A deficiency by screening at-risk populations (e.g., children under 5, pregnant women, malnourished individuals) by simply asking about difficulty seeing at night.
Prompt identification and administration of high-dose Vitamin A can completely reverse night blindness and prevent progression to irreversible blindness from corneal damage.
In the Indian context, the National Vitamin A Prophylaxis Programme provides high doses of Vitamin A to children aged 9 months to 5 years to prevent deficiency.

How to Approach the Question

This is a factual recall question that tests your knowledge of a specific nutritional deficiency.
First, identify the core concept: Vitamin A deficiency and its signs.
Recall the primary function of Vitamin A in the body, particularly its role in the visual cycle (formation of rhodopsin for night vision).
Understand that functional impairments (like difficulty with night vision) often precede visible structural changes (like spots or ulcers on the eye).
Evaluate each option based on the known progression of the disease (xerophthalmia). Night blindness is the earliest functional symptom.
Eliminate options that represent later, more severe stages (Corneal ulceration, Bitot's spots) or are non-specific (Muddy eyes).

Concept Tested & Keywords

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E6 Parks TextBook of Preventive & Social Medicine part 2 — Subpart A (pp 1-232 of 464) pp. 150-152, 151-153

E6 textbook of Applied Biochemistry and Nutrition & DieteticsHarbans Lal (pp 26-464 of 479) p. 361-363