Pernicious anaemia is caused by the deficiency of?

Appeared in: Central Institute of Psychiatry - 9 July 2022

Explanation

Pernicious anaemia is a specific form of megaloblastic anaemia.
It is caused by the inability to absorb Vitamin B12 from the diet, not a dietary lack itself.
This malabsorption is due to a deficiency of intrinsic factor (IF), a protein secreted by the stomach's parietal cells, which is essential for B12 absorption in the ileum.
The underlying cause is often an autoimmune attack on the parietal cells or intrinsic factor.
Vitamin B12 (cobalamin) is crucial for DNA synthesis in red blood cells and for maintaining the myelin sheath of nerves.

Option A: Vitamin B1 (Thiamine) deficiency does not cause pernicious anaemia.
Option C: Vitamin B6 (Pyridoxine) deficiency is not the cause of pernicious anaemia.
Option D: This is a duplicate of option A. Vitamin B1 (Thiamine) deficiency does not cause pernicious anaemia.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Causes of Pernicious Anaemia as background academic context rather than a clinical decision trigger.
Understanding that pernicious anaemia is an absorption problem, not a dietary one, is critical for nursing management. Oral B12 supplements are ineffective; treatment must be parenteral (injections).
Nurses must educate patients that treatment is lifelong. Stopping B12 injections will cause the symptoms to return and can lead to permanent, irreversible nerve damage.
What if? A patient with pernicious anaemia also has a history of chronic alcoholism. The nurse should be vigilant for signs of both Vitamin B12 and Vitamin B1 (Thiamine) deficiency, as alcoholism puts the patient at high risk for both.

How to Approach the Question

First, identify the core concept in the question: the cause of 'pernicious anaemia'.
This is a direct recall question testing your knowledge of haematological disorders and vitamin deficiencies.
Recall the specific definition of pernicious anaemia. While it's a B12 deficiency anaemia, the term 'pernicious' specifically refers to the cause being a lack of intrinsic factor.
Evaluate the options. Each option is a different B vitamin.
Connect the condition (pernicious anaemia) to the correct vitamin deficiency (Vitamin B12).
Eliminate the other options by recalling the conditions associated with their deficiencies (e.g., B1 with Beriberi, B6 with neuropathy).

Concept Tested & Keywords

QXBz1LUOQBX5KzofVvo37Q

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

E6 Medicine Harrison 22e Part 2 p. 510-512

Practise the full Central Institute of Psychiatry - 9 July 2022

Attempt every question from this paper in a timed mock, then review the full solution for each one.