All Sample Questions

Megaloblastic Anemia Due to Vitamin B12 Deficiency 1

Question

Vignette: A 32-year-old woman comes to the doctor's office complaining of severe fatigue and shortness of breath. She says that she has been feeling like this for a few months now. She also complains of having severe heartburns. On examination, her skin and conjunctiva appear pale. Her blood tests show low hemoglobin with mean corpuscular volume (MCV) of 110 fL. Her serum folate level is normal but her serum vitamin B12 level is low.

Question: Which of the following pathological findings is most likely to be seen in the bone marrow of this patient?

Choices

A. Hypocellular marrow with fat atrophy

B. Hypercellular marrow with erythroid hyperplasia

C. Hypercellular marrow with myeloid hyperplasia

D. Hypocellular marrow with fibrosis

E. Normocellular marrow with normal maturation

Answer

B. Hypercellular marrow with erythroid hyperplasia

Explanation

This patient's clinical picture and lab findings are suggestive of vitamin B12 deficiency, which can lead to macrocytic anemia. Vitamin B12 is necessary for DNA synthesis. Its deficiency leads to ineffective erythropoiesis, resulting in large, immature, nucleated red cells (megaloblasts) in the bone marrow and macrocytes in the peripheral blood. The bone marrow in vitamin B12 deficiency is typically hypercellular, with erythroid hyperplasia. The erythroid precursors are larger than the normal, with open chromatin and prominent nucleoli, a characteristic finding in megaloblastic anemia.