A 34-year-old man on zidovudine-based antiretroviral therapy presents with fatigue and pallor. Hemogram shows hemoglobin 7.8 g/dL and macrocytosis with elevated mean corpuscular volume. The most likely cause is:

• A Parvovirus B19 induced pure red cell aplasia
• B Autoimmune hemolytic anemia related to HIV infection
• C Iron deficiency from chronic HIV enteropathy
• D Zidovudine induced bone marrow suppression ✓

Explanation

Zidovudine, a thymidine nucleoside analogue, is the NRTI best known for dose related bone marrow suppression causing macrocytic anemia and neutropenia, especially at higher doses and in advanced disease. The macrocytosis itself is a characteristic clue and often appears even without anemia. Parvovirus causes pure red cell aplasia rather than macrocytic anemia, and iron deficiency produces microcytosis, so both fail to fit the blood picture described.

Reference: Katzung Basic and Clinical Pharmacology, 15th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.