A 26-year-old man who is HIV positive has a CD4+ T-lymphocyte count of 250/mm3 (N≥500). After 5 weeks of therapy with two nucleoside reverse transcriptase inhibitors and a protease inhibitor, he feels weak and is easily fatigued. His hemoglobin concentration has decreased from 12.8 g/dL to 8.2 g/dL. Which of the following is the most likely cause of the anemia in this patient?
1.Decreased formation of erythrocytes
2.Folic acid deficiency
3.Increased formation of erythrocyte antibodies
4.Increased fragility of erythrocytes
5.Iron deficiency
Correct answer
Decreased formation of erythrocytes
Explanation
The commonly-used HIV medications have well-known side effects. In particular, zidovudine (AZT), the commonly-used nucleoside reverse transcriptase inhibitor (NRTI), may cause anemia through (A) decreased formation of erythrocytes. Approximately 1% of patients experience this adverse effect after 2-4 weeks of taking the medication. Other significant side effects of AZT are headache (63%), malaise (53%), nausea (51%), anorexia (20%), vomiting (17%), constipation (6%), and granulocytopenia (2%), anemia (1%).
Folic acid deficiency and (E) iron deficiency may, respectively, cause macrocytic and microcytic anemia, but they are not in and of themselves related to HIV medications. Similarly, these medications do not affect © the formation of erythrocyte antibodies or (D) the fragility of erythrocytes.