Pellagra is caused due to the deficiency of?

BCCL kharkhanda Staff Nurse - 2015

Applied Nutrition & Dietetics

Easy

Appeared in: BCCL kharkhanda Staff Nurse - 2015

Explanation

Pellagra is the clinical condition resulting from a severe deficiency of niacin (Vitamin B3).
The classic signs of pellagra are often remembered by the '3 D's': Dermatitis (a photosensitive rash, especially around the neck, known as Casal's necklace), Diarrhea, and Dementia.
Niacin is crucial for cellular metabolism as it is a precursor to the coenzymes NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate), which are essential for numerous oxidation-reduction reactions.
Deficiency can arise from a diet lacking in niacin and its precursor, the amino acid tryptophan, which is common in populations with a diet based on untreated maize (corn).

Option A: Thiamine (Vitamin B1) deficiency is the cause of Beriberi, not Pellagra. Beriberi primarily affects the nervous system (dry beriberi) and the cardiovascular system (wet beriberi).
Option C: Pyridoxine (Vitamin B6) deficiency does not cause Pellagra. Its deficiency is associated with conditions like microcytic anemia, dermatitis, and neurological symptoms such as confusion and depression.
Option D: Riboflavin (Vitamin B2) deficiency causes a condition called ariboflavinosis, which is distinct from Pellagra. Symptoms include cheilosis (cracks at the corners of the mouth) and glossitis (inflamed tongue).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Vitamin Deficiency Diseases as background academic context rather than a clinical decision trigger.
Nurses must be able to recognize the signs of pellagra, especially in at-risk populations such as individuals with alcoholism, malabsorptive disorders (e.g., Crohn's disease), or those on restrictive diets, to ensure prompt diagnosis and intervention.
Patient education is a critical nursing function. This includes teaching about dietary sources of niacin (e.g., meat, fish, nuts, fortified grains) and the importance of a balanced diet to prevent deficiency.
What if? If a patient presents with dementia and a history of chronic alcoholism, a nurse should consider deficiencies of both Niacin (Pellagra) and Thiamine (Wernicke-Korsakoff syndrome), as symptoms can overlap and both are common in this population.

How to Approach the Question

Identify the key term in the question stem, which is 'Pellagra'.
This is a factual recall question that requires knowledge of vitamins and their associated deficiency diseases.
Systematically review each option and recall the primary disease linked to its deficiency.
Thiamine (B1) deficiency causes Beriberi.
Niacin (B3) deficiency causes Pellagra.
Pyridoxine (B6) deficiency is linked to anemia and neuropathy.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 734-736

E6 Textbook of Biochemistry for medical StudentsDM Vasudevan Part 2 — Subpart A (pp 1-239 of 478) p. 138-140

E6 Medicine Harrison 22e Part 2 p. 512-514