[Characteristics of respiratory functional involvement in MacLeod's syndrome (or Swyer-James syndrome)].

MacLeod's syndrome (Swyer-James' syndrome in the child) is a radiologic entity: hyperlucency of one or several lobes, or even of one lung, scarce hilar shadow on the same side as the abnormal transradiency, and barely visible arterial network on the abnormal side of the thorax. Distal bronchiectases (bronchography) and abnormal distal bronchi (necropsy) suggest that this disease may be due to bronchiolitis in childhood. An obstructive pulmonary disorder, assessed by pulmonary function tests, has been described in this syndrome. However, neither the prevalence nor the severity or evolution of the obstructive defect are known. We have studied two such patients for 5 and 12 years respectively: during this long follow-up period the obstructive disorder, albeit severe, remained stable. We have also analysed the 75 cases in the literature in which pulmonary function tests are available and comparable. We have been able to show that (1) an obstructive disorder is frequent in MacLeod's syndrome, (2) the severity of this disorder differs markedly between patients, and (3) this airflow limitation is probably stable on a long-term basis. These findings are compatible with the pathogenetic hypothesis at present accepted, ie bronchiolitis during childhood, and suggest that the inflammatory bronchial disease may have been generalized in many such patients.