PULMONARY MANIFESTATIONS IN PEDIATRIC-PAT IENTS WITH SICKLE-CELL-ANEMIA

The lung is a target organ in sickle cell anemia. Because its capillar y network is well developed, it is often the site of infection and thr ombosis, which lead to acute and/or chronic pulmonary manifestations. Hypoxia with a decrease in arterial blood oxygen content, a paradoxica l increase in the partial pressure of oxygen in venous blood, and redu ced affinity of oxygen for the abnormal hemoglobin are the most signif icant pathophysiologic factors. The cardiac index is consistently incr eased, as a result of both tachycardia and an increase in systolic str oke volume. Peripheral arterial resistance is nearly halved at rest an d during exercise. The compensatory changes seem out of proportion wit h the severity of the anemia, and there is a paradoxical decrease in t he peripheral extraction of oxygen. The main acute pulmonary complicat ion is acute chest syndrome (ACS), with chest pain, dyspnea and abnorm al physical findings upon examination of the chest. ACS can be produce d by a thoracic vasooclusive crisis or a life-threatening complication such as pulmonary thrombosis or embolism, infection, alveolar hypoven tilation, or pulmonary edema. Sickle cell anemia is responsible for fa ilure to thrive with decreased chest size and lung size. Lung function tests are normal during childhood. Pulmonary fibrosis and pulmonary h ypertension can develop in adulthood as a result of recurrent episodes of microvascular occlusion. Early diagnosis of pulmonary complication s and close lung function monitoring are essential. It would be of use to determine the factors associated with an increased risk of pulmona ry abnormalities in sickle cell anemia patients.