[Changes in blood coagulation in HIV infection].

The human immunodeficiency virus (HIV) infection is becoming more complex. Hemostatic abnormalities occur frequently in the patient with HIV. HIV-related thrombocytopenia (Tr-HIV) is the most common hemostatic disorder with a high morbidity and affects patients from every risk group independently of age, sex, or stage of infection. Two mechanisms are responsible for the Tr-HIV: bone marrow failure and immunological disorders, namely, circulating immune complex deposited on the platelet membrane and the production of autoantibodies directed against platelets. The treatment of choice is zidovudine; other available options are not as effective as zidovudine. In addition, there are some abnormalities in the fluid phase of the coagulation cascade which can produce bleeding or thrombosis in the HIV patient. The most common are a prolonged partially activated thromboplastin time test, the production of a lupic anticoagulant and anticardiolipin antibodies, and several abnormalities in the natural-occurring anticoagulants. The thrombotic thrombocytopenic purpura recently associated with HIV has a clinical presentation and treatment alternatives that closely resemble those for the classical disease. The knowledge of these hemostatic abnormalities in the HIV seropositive patient allows a more rational care of these patients.