THE LUNG IN SICKLE-CELL-ANEMIA IN CHILDRE N AND ADULTS

The pulmonary complications remain the prime cause of morbidity and mo rtality in sickle cell disease. The pathogenetic mechanisms consists b oth of an alteration of the rheological properties of the blood, the e xistence of a hypercoagulability state and above all specific interact ions between the abnormal sickle cells and the vascular endothelium an d a dysregulation of the vascular reactivity in which nitrous oxide in tervenes. The acute chest syndrome (ACS) is characterised by chest pai n with dyspnoea and recent radiological abnormalities and it is an acu te lung complication whose problem is one of aetiology. The infectious pneumonias are rarely decremented. On the other hand, alveolar hypove ntilation linked to infarcts of the thoracic ribs, thoracoabdominal tr auma, subdiaphragmatic pain, the administration of analgesics causing respiratory depression, obesity or sleep disturbance are frequent caus es of ACS. Bronchoalveolar lavage has revealed a frequency of fat embo li following infarcts in the long bones. Pulmonary emboli is rarely a cause. Pulmonary thrombosis is a serious complication, the diagnosis i s difficult and is seen in a predisposed clinical setting. The treatme nt of ACS rests on controlled hydration and antibiotic therapy oxygen therapy and controlled analgesic therapy. The indications for blood tr ansfusion and for exchange transfusion merits a better evaluation In t he long term patients with sickle cell disease present with a failure of normal thoracopulmonary growth with a restrictive ventilatory defec t and progressive diminution in the transfer factor of carbon monoxide with age. A history of ACS favours chronic lung disease. Pulmonary ar terial hypertension is less frequent.