The diagnosis of pulmonary thromboembolism in sickle cell disease

The symptoms of thromboembolism in sickle cell anemia patients with acute chest syndromes are difficult to differentiate from the similar symptoms of painful thoracic crises and infectious pulmonary episodes. Furthermore, the chronic pulmonary abnormalities in sickle cell disease frequently contribute to the confusing results of noninvasive diagnostic procedures usually employed in evaluating pulmonary thromboembolism. In this study the chronic pulmonary status of asymptomatic sickle cell patients was defined, and this information was used in the evaluation of patients with acute chest syndromes suggestive of pulmonary thromembolism. Sixteen asymptomatic sickle cell patients were prospectively studied by chest roentgenography, spirometry, arterial gas analyses, and radioisotopic lung scans. There was an appreciable degree of preexisting chronic restrictive lung disease with mild to moderate arterial hypoxemia and abnormal lung scans in more than half of the patients. These prospective baseline data were incorporated into the diagnostic evaluation of four of these patients who later developed an acute chest syndrome suggestive of pulmonary thromboembolism. Determination of the cause of the chest pain was greatly faciliated by the existence of the baseline pulmonary data. In another patient persistence of abnormal studies following a presumed thromboembolic episode aided diagnostic evaluation when another episode of chest pain occurred. The findings indicate that comprehensive pulmonary studies in sickle cell patients while in an asymptomatic state will provide baseline data which aid the evaluation of possible pulmonary thromboembolism in acute chest syndromes without resorting to high-risk invasive studies.