Pernicious anaemia is caused by the deficiency of:

DSSSB 13 August 2024

Medical & Surgical Nursing

Easy

Appeared in: DSSSB 13 August 2024

Explanation

Pernicious anemia is an autoimmune disorder where the body's immune system attacks the parietal cells of the stomach.
These parietal cells are responsible for producing Intrinsic Factor (IF), a protein crucial for vitamin absorption.
Intrinsic Factor is essential for the absorption of Vitamin B12 in the terminal ileum.
The destruction of parietal cells leads to a lack of IF, causing impaired absorption and subsequent deficiency of Vitamin B12.
This deficiency results in megaloblastic anemia and can lead to irreversible neurological damage if left untreated.

Option A: Vitamin C (ascorbic acid) deficiency causes scurvy, which affects collagen synthesis, leading to symptoms like bleeding gums, poor wound healing, and petechiae. It is not related to pernicious anemia.
Option B: Vitamin B6 (pyridoxine) deficiency can cause a different type of anemia called sideroblastic anemia, as well as peripheral neuropathy, cheilosis, and glossitis. It does not cause the megaloblastic changes seen in pernicious anemia.
Option C: Vitamin B5 (pantothenic acid) deficiency is extremely rare in humans. When it does occur, it can cause symptoms like fatigue, insomnia, and a burning sensation in the feet, but it is not associated with any form of anemia.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pathophysiology of pernicious anemia and its relation to vitamin deficiencies as background academic context rather than a clinical decision trigger.
Patients with pernicious anemia require lifelong Vitamin B12 replacement therapy, typically via intramuscular or deep subcutaneous injections, because the oral route is ineffective due to the lack of intrinsic factor.
Nurses must monitor for both hematologic improvement (e.g., rising hemoglobin, decreased MCV) and neurologic status (e.g., paresthesias, gait, memory), as neurologic damage can be irreversible if treatment is delayed.
What if? If a patient with pernicious anemia develops iron deficiency as well (a dimorphic anemia), their blood smear would show both large macrocytes and small microcytes. This can happen after B12 therapy starts, as rapid red cell production consumes iron stores.

How to Approach the Question

This is a factual recall question that tests your knowledge of the specific cause of a named disease.
First, identify the key term in the question: 'Pernicious anaemia'.
Recall the specific pathophysiology of this condition. The term 'pernicious' suggests a complex, insidious process, not just a simple dietary lack.
Associate pernicious anemia with its unique mechanism: an autoimmune attack on the stomach leading to a lack of Intrinsic Factor.
Connect the lack of Intrinsic Factor to its sole purpose: facilitating the absorption of Vitamin B12.
Evaluate the options. Eliminate vitamins linked to other well-known deficiency diseases (e.g., Vitamin C and scurvy) to confirm your answer.

Concept Tested & Keywords

Concept Tested: Pathophysiology of pernicious anemia and its relation to vitamin deficiencies.
Stem keywords: Pernicious anaemia, deficiency
Lead-in keywords: caused by
Negative lead-in flag: false

QlLJale8EwNx5TRAKOPHfv

E6 PATHOLOGY QUICK REVIEWBased on Harsh Mohan Textbook of PATHOLOGY p. 104-106

E6 Medicine Davidson Principles Practice 24e p. 964-966

E6 Pharmacology Katzung 16e p. 934-936