Pernicious anemia results due to :
1.vit B12 deficiency resulting from inadequate intrinsic factor
2.Folic acid deficiency resulting from inadequate intrinsic factor
3.Vit B12 deficiency resulting from inadequate extrinsic factor
4.Al of the above
๐ Explanation:
The correct answer for the MCQ is option 1: Pernicious anemia results from
vitamin B12 deficiency resulting from inadequate intrinsic factor. This is
because pernicious anemia is specifically caused by the body's inability to
absorb vitamin B12 due to a lack of intrinsic factor, which is required for the
absorption of vitamin B12 in the small intestine. Folic acid deficiency, while
it can also cause megaloblastic anemia, is not directly associated with
intrinsic factor and is a separate entity from pernicious anemia.
1. Vitamin B12 deficiency resulting from inadequate intrinsic factor:
Vitamin B12 is an essential nutrient that plays a critical role in the
production of healthy red blood cells. It is involved in the synthesis of DNA
and the metabolism of fatty acids and amino acids. Intrinsic factor is a protein
produced by the parietal cells of the stomach that binds to vitamin B12,
allowing it to be absorbed in the small intestine. When there is a deficiency of
intrinsic factor, vitamin B12 cannot be effectively absorbed from food, leading
to vitamin B12 deficiency anemia. This is the most common cause of pernicious
anemia.
Pernicious anemia is an autoimmune disorder where the body's immune system
mistakenly attacks the stomach cells that produce intrinsic factor. Without
sufficient intrinsic factor, vitamin B12 cannot be absorbed, resulting in a
decrease in the number of red blood cells produced. The red blood cells that are
formed are abnormally large and immature, known as megaloblasts. These cells are
not efficient at carrying oxygen and are destroyed more quickly than normal
cells, leading to the symptoms of anemia such as fatigue, weakness, and pallor.
The deficiency in vitamin B12 can also affect the nervous system, causing
neuropathy, cognitive impairment, and other neurological symptoms.
2. Folic acid deficiency resulting from inadequate intrinsic factor:
Folic acid is another B-vitamin essential for the production of red blood cells
and is involved in DNA synthesis. However, folic acid deficiency is not directly
caused by a lack of intrinsic factor. Folic acid is absorbed in the small
intestine through a different mechanism than vitamin B12. While folic acid
deficiency can also lead to megaloblastic anemia, it is not typically referred
to as pernicious anemia. Pernicious anemia is specifically associated with
vitamin B12 deficiency due to intrinsic factor deficiency or malabsorption.
3. Vitamin B12 deficiency resulting from inadequate extrinsic factor:
The term "extrinsic factor" is not commonly used in the context of vitamin B12
deficiency. Vitamin B12 is derived from dietary sources such as meat, fish, and
dairy products. In the context of pernicious anemia, the issue is with the
intrinsic factor, which is necessary for the absorption of vitamin B12.
Therefore, this option is not accurate for explaining the cause of pernicious
anemia.
MCQ