Richard D. Moore, M.D.
- Consider non-HIV-related causes of thrombocytopenia: malaria, typhoid fever, louse-borne relapsing fever, hemorrhagic fevers, leptospirosis, brucellosis, rickettsial infections and kala-azar.
- Consider non-infectious causes, including nutritional (severe vitamin B12 deficiency) and alcohol abuse.
- Thrombocytopenia may be common in untreated HIV+ patients in sub-Saharan Africa (up to ~25%), but anemia and lymphopenia more common.
- No information on idiopathic thrombocytopenic purpura (ITP) in HIV+ African populations.
- In a study from Uganda of patients on AZT- or d4T-based regimens, incidence of severe thrombocytopenia (<50,000/mm3) was only ~1%.
Zambia Information Author: Paul Auwaerter, M.D.
- 1-yr incidence ranges from 1.7% with asymptomatic HIV to 3.1% with CD4-define AIDS to 8.7% with AIDS-defining illness.
- Increased risk with decreasing CD4, injection drug use, African-American race, anemia. Other causes include alcohol abuse, sulfonamides, thiazides, folate and vitamin B12 deficiency, IV cocaine.
- Idiopathic thrombocytopenic purpura (ITP) a major cause. Production of autoantibodies against certain platelet antigens (PA-IgG). Antibody-coated platelets removed by macrophages in the spleen.
- Increased risk of bleeding with PLT <10,000-20,000.
- Heparin-induced thrombocytopenia may be more common in HIV-infected than uninfected
- Low PLT count, usually with other blood elements normal.
- Bone marrow shows increase in megakaryocytes in response to PLT phagocytosis in ITP. Megakaryocytes may be decreased in HIV-TP without ITP. Other hematologic elements may be normal.
- Bone marrow Bx rarely necessary with isolated thrombocytopenia.
- HIV-associated thrombocytopenia responds to antiretroviral therapy. Best data with AZT:(600 mg/day;sometimes up to1000 mg/day); however, most ART probably effective
- Use most appropriate regimen to suppress VL and improve immune status. Consider AZT if no response to initial regimen.
- Prednisone: 80-90% response rate. Initial dose is 1 mg/kg/day or 60-100 mg/d. Unknown whether long-term use may increase risk of HIV progression or fulminant Kaposi's sarcoma in men co-infected with HHV8.
- Intravenous immune globulin (IVIG) at 1000 mg/kg x 2 days. Response with significant increase (>100,000) in PLT counts within 24-48 hrs. High cost: reserve for acute bleeding or urgent need for invasive surgical procedure. Acute renal failure secondary to sucrose load reported with some preparations (Sandoglobulin, Panglobulin, Gammar-P.I.V, and Gammar-I.V.b.).
- IV or IM anti-Rh immunoglobulin (anti-D, winRho) in nonsplenectomized Rh-positive pts produces response. Hemolysis with decrease in hemoglobin of >2 gm/dL, fever, and chills seen in 5-10% of pts.
- Splenectomy, if refractory to above. Long-term response in approximately 60% of pts. Risk of infection with encapsulated bacteria after splenectomy (S. pneumoniae, H. influenzae). Need for pneumococcal vaccine.
- Other treatment modalities, such as dapsone, interferon, vincristine, danazol, low-dose splenic irradiation have shown limited success in ITP.
- For active bleeding, packed RBCs and PLT transfusion plus IVIG. (Prednisone has slower onset of action than IVIG).
||Preferred treatment for ITP (after HAART).
intravenous immune globulin
||Reserve use for acute bleeding or urgent need for surgical procedure.
rho (D) immune globulin
||If prednisone ineffective, use in non-splenectomized Rh-positive pts.
- Even with effective treatment, relapse can occur in 10-20%. Effective HAART may minimize relapse.
- Consider maintenance dose of prednisone, IVIG, or anti-Rh immunoglobulin.