Pulmonary and cardiac function in sickle cell lung disease: preliminary report.

Physicians have long been intrigued by the unusual cardiac and pulmonary manifestations which may occur in patients with sickle cell anemia. Cardiomegaly, systolic and diastolic murmurs, recurrent bouts of pulmonary infiltration and chest pain, episodic or chronic dyspnea all of these may appear in the sicklemic individual. In recent years, considerable investigation has been carried out to define the anatomic and physiologic substrates upon which these fascinating clinical abnormalities are based. Such study has indicated that patients with sickle cell anemia have three major defects which may influence cardiopulmonary function: (1) a chronic and usually severe anemia; (2) an abnormal form of hemoglobin, designated as S hemoglobin; and (3) a tendency to develop multiple zones of pulmonary thrombosis. While each of these factors contributes to clinical disability, it is the occurrence of repeated pulmonary thromboses which may lead to the development of the interesting clinical entity which we have labeled “sickle cell lung disease.” Clinically, sickle cell lung disease parallels the well-known syndrome of multiple pulmonary emboli.”2 Characteristically, the symptoms and signs of thrombosis vary widely. Recurrent episodes of poorly-defined chest discomfort or frank, pleuritic chest pain may occur. Fever and some dyspnea are common with these episodes, although hemoptysis is rare. Small infiltrations which heal by linear scarring may appear on serial chest roentgenograms (Fig. 1). A variable degree of leucocytosis may occur. In our experience, the search for pathogens in the sputum is usually unrewarding. Furthermore, resolution of the fever, leucocytosis and roentgenographic abnormalities occur in the same time-period whether or not antibiotic therapy is instituted. These thrombotic episodes are usually diagnosed as “pneumonitis” or non-specific manifestations of sickle cell “crisis.”1 Occasionally, in patients who have experienced this syndrome repeatedly, evidence suggesting residual cardiopulmonary disease appears in the form of excessive fatigue, dyspnea with mild exercise and cardiac enlargement especially of the right ventricular type. Cyanosis is rarely seen, however, probably because of the severity of the anemia. Microscopic sections of the lung indicate that sickle thrombi occur chiefly in the pulmonary capillaries and smaller arterioles (Figs. 2, 3). If widespread obstruction has occurred, right ventricular enlargement may be found at direct examination.35