Family Nurse Practitioner Exam

What is the primary defect in pernicious anemia?

1. A) Iron deficiency

2. B) Vitamin B12 malabsorption

3. C) Folic acid deficiency

4. D) Hemolysis

The correct answer is: B) Vitamin B12 malabsorption

The primary defect in pernicious anemia is indeed vitamin B12 malabsorption. This condition arises due to an autoimmune response that attacks the gastric mucosa, ultimately leading to a deficiency in intrinsic factor, a protein essential for the absorption of vitamin B12 in the intestines. Without sufficient intrinsic factor, vitamin B12 cannot be adequately absorbed from dietary sources, resulting in a deficiency that can affect red blood cell formation and lead to macrocytic anemia. Pernicious anemia specifically points to this malabsorption issue, highlighting its distinction from other types of anemia that may stem from different nutritional deficiencies or pathological processes. Understanding this underlying mechanism is crucial for recognizing the clinical manifestations and appropriate treatment modalities associated with pernicious anemia, which often involves vitamin B12 supplementation to address the absorption defect.