Pulmonary Disorders in Persons With Sickle Cell Anemia
Pulmonary Complications of HIV Infection
Describe the pathogenesis, clinical features, and treatment of pulmonary disorders that occur in patients with sickle cell anemia.
Discuss the pathogenesis, clinical features, and treatment of lung disease in patients with liver disease.
Describe the types of pulmonary disorders that occur in association with HIV infection, and how the spectrum of diseases is modified with the use of antiretroviral therapy.
Sickle cell anemia is accompanied by several pulmonary complications. Acute chest syndrome includes chest pain, fever, and pulmonary opacities, usually in the setting of an acute painful crisis. Mechanisms for acute chest syndrome include vasoocclusion, fat embolism, and vasoconstriction, the latter related at least in part to scavenging of nitric oxide by free hemoglobin. Patients with severe liver diseases may develop hepatopulmonary syndrome, characterized by hypoxemia caused by dilation of the pulmonary capillary bed and arteriovenous shunts; portopulmonary hypertension similar to idiopathic pulmonary hypertension; and hepatic hydrothorax. Lung cancer occurs with increased frequency in HIV-positive persons and appears to present in more advanced stages and with a more aggressive course than in HIV-negative persons. The incidence of pulmonary arterial hypertension is also increased with HIV infection; it may occur in any CD4+ stratum and is in all respects similar to idiopathic arterial hypertension in HIV-negative persons. Immune reconstitution inflammatory syndrome (IRIS) occurs when antiretroviral treatment inhibits viral replication and CD4+ lymphocyte counts and activity increase.