USMLE PRACTICE QUESTION OF THE WEEK
Question for September 5, 2025
A 24-year-old woman presents to the clinic with a 3-month history of fatigue and pallor. She has heavy menstrual bleeding during her periods. She follows a vegetarian diet but admits to irregular eating habits. Physical examination shows pale conjunctivae and a soft systolic murmur.
Laboratory studies reveal:
Hemoglobin: 8.1 g/dL
Mean corpuscular volume (MCV): 70 fL
Serum ferritin: Low
Total iron-binding capacity (TIBC): Elevated
Which of the following is the most likely cause of her anemia?
Laboratory studies reveal:
Hemoglobin: 8.1 g/dL
Mean corpuscular volume (MCV): 70 fL
Serum ferritin: Low
Total iron-binding capacity (TIBC): Elevated
Which of the following is the most likely cause of her anemia?
Correct Answer:
C. Iron deficiency
Correct Answer Explanation
The patient's microcytic anemia, low ferritin, elevated TIBC, and history of heavy menses suggest iron deficiency anemia, the most common cause in young women with menstrual blood loss.
Why These Are Incorrect:
- A. Anemia of chronic disease typically presents with normal or high ferritin and low TIBC.
- B. Folate deficiency causes macrocytic anemia, not microcytic.
- D. Thalassemia minor causes microcytosis but usually with normal iron studies.
- E. B12 deficiency causes macrocytosis, not microcytosis.