Anemia

• In the current ART era, prevalence of anemia is 7-50%; increasing incidence occurs when CD4 count < 200 cells/microL.
• Hypoproliferative anemia (normochromic, normocytic anemia with low reticulocyte count and normal iron stores) most common type of anemia associated with HIV infection.
• Earliest Sx affect functional status: easy fatigue, weakness, exertional dyspnea, slowed cognition (Hgb < 10-11).
• Later Sx include rapid heart rate, bounding pulse, dyspnea, severe fatigue, confusion, angina, CHF (Hbg < 8-9).
• HIV can directly cause suppression of hematopoietic precursor cells in marrow through inflammatory cytokine suppression, inhibition of endogenous erythropoietin response.
• Hypogonadism (low testosterone level) can cause anemia.
• Anemia associated with worse survival in HIV, but unlikely causal. May be impaired erythropoiesis from HIV-associated chronic inflammation. Hgb independent factor in prognostic indices for mortality and morbidity.

MORE CLINICAL

Work-up and differential should be guided by acuity, severity and CD4 count of patient.

• Patients acutely ill with a low CD4 count (< 200 cells/microL), need to consider underlying opportunistic infections, malignancies and other rare causes (TMAs - thrombotic microangiopathies; HLH - hemophagocytic lymphohistiocytosis; HHV-8 - human herpes virus 8-associated disorders). Patients may also have other cytopenias in addition to anemia.
• Stable patients with CD4 count >200 cells/microL on ART, need to consider non-HIV-associated causes starting with a review of medications and guided by MCV, reticulocyte count and iron studies.
• Stable patients with CD4 count >200 cells/microL not on ART, need to consider starting patient on ART and reassessing.

Table below is not exhaustive but outlines some of the most common causes of anemia in HIV patients and their associated laboratory findings.