PAEA Surgery End Of Rotation (EOR) Practice Exam

What is the primary cause of macrocytic anemia?

1. Iron deficiency

2. Vitamin B12 deficiency

3. Chronic disease

4. Sickle cell disease

The correct answer is: Vitamin B12 deficiency

Macrocytic anemia is primarily characterized by the presence of large red blood cells (macrocytes) in the bloodstream. The most common underlying cause of this condition is a deficiency in vitamin B12 or folate. Specifically, vitamin B12 deficiency leads to impaired DNA synthesis during red blood cell production, resulting in the formation of abnormally large red blood cells. This is also known as megaloblastic anemia. Vitamin B12 is essential for proper red blood cell formation and neurological function; therefore, its deficiency not only leads to macrocytic anemia but can also produce neurological symptoms like peripheral neuropathy. In cases where there is a deficiency of folate, similar mechanisms of DNA synthesis disruption occur, but vitamin B12 deficiency is more commonly associated with macrocytic anemia. Other causes listed, such as iron deficiency and chronic disease, lead to microcytic anemia, characterized by smaller red blood cells due to different underlying mechanisms. Sickle cell disease, on the other hand, results in the production of abnormally shaped red blood cells, which does not lead to macrocytic anemia but rather anemia due to hemolysis and other complications. Therefore, vitamin B12 deficiency is the most accurate and relevant choice for the primary cause of macrocytic