Lung function in diastrophic dysplasia

Diastrophic dysplasia (DD) is a rare skeletal dysplasia characterized by short-limbed short stature, contractures and early degeneration of joints, and spinal deformities such as scoliosis. Mortality is increased in the neonatal period, in part due to tracheo- and bronchomalacia. Additionally, spinal deformities are very rigid, decreasing mobility of the chest cage. The aim of our study was to evaluate lung volumes and airway flow dynamics in patients with DD. A total of 31 patients (12 males, 19 females) underwent a detailed clinical examination measurements of standing height PA-radiography of the spine, flow-volume spirometry, and body plethysmography. The patients were assigned to two groups: children and adolescents (0-18 years, n = 18) and adults (over 18 years, n = 13). The mean spirometric parameters were mostly within the predicted value range, although the variation was wide. At least one abnormally low spirometry parameter was found in 6 (33%) of the children and adolescents and in 7 (54%) of the adults. Mean forced vital capacity (FVC) was 104% (range 48-163%) of predicted values in the children and adolescents and 95% (58-140%) of the adults. Peak expiratory flow (PEF) values were abnormal in 4 (22%) of the children and adolescents and in 5 (39%) adults. The mean plethysmographic parameters were all within the predicted value range. At least one abnormal plethysmographic value was found in 6 (33%) of the children and adolescents and in 4 (31%) of the adults. Airway resistance (Raw) was significantly higher in the adults than in the children and adolescents (P = 0.016), and was abnormally high in 3 (23%) of the adults. The angle of thoracic or thoracolumbar scoliosis correlated with the percentages of the predicted values of FVC (r(s) = - 0.66), forced expired volume in 1 sec (FEV(1)) (r(s) = - 0.56), and total lung capacity (TLC) (r(s) = - 0.67). Age correlated with the FEV(1)/FVC ratio (r(s) = - 0.41), with the maximal expired flow at 50% FEV (MEF(50)) values (r(s) = - 0.55), with the residual volume (RV) values (r(s) = - 0.47), and with the RV/TLC ratio (r(s) = - 0.43). Variable bronchial obstruction was found in 1 (6%) child and in 2 (17%) adults. Although the patients with DD had, on average, normal lung volumes, large individual variation occurred. Airway resistance was increased in adults. The angle of scoliosis correlated inversely with lung volume parameters.