[Spontaneous pneumothorax in Duchenne muscular dystrophy].

We retrospectively studied an incidence and clinical features of spontaneous pneumothorax (SPT) in Duchenne muscular Dystrophy (DMD) from chest roentgenograms and clinical records of our 50 inpatients, comparing those in severely mentally and physically disabled patients. Nine out of 50 (18%) DMD patients experienced SPT, and their chest roentgenograms showed no evidence of underlying pulmonary disease such as bulla, bleb, pneumonia. They were all asymptomatic. Clinical course was well, however, relapse occurred in 4 cases. The onset age was 20 or more in 7 patients (78%), and the incidence of SPT in patients aged 20 or more was 31%, which was 7.4 times higher than that of younger patients. Body weight at the onset of SPT was all below 30 kg, tended to be lower than that of SPT negative cases. Some patients experienced SPT after having lost their weight. SPT occurred much more frequently on the right side (right only, 7 cases; left only, 0; bilateral, 2 cases). Thoracic deformity and artificial ventilation were not major risk factors. We examined chest roentgenograms of 41 severely mentally and physically disabled inpatients, age, sex, and body weight matched and found no SPT. We conclude that SPT is frequent and asymptomatic in DMD and the major risk factors of SPT are age (above 20 years old) and body weight (below 30 kg), while thoracic deformity, and artificial ventilation are not essential.