Comparative study of mediastinal emphysema as determined by etiology.

OBJECTIVE To evaluate the difference in the clinical features of mediastinal emphysema as classified into three groups based on etiology; patients in whom it was spontaneous with unknown etiology (A group), those in whom it was secondary to bronchial asthma (B group), and those in whom it was secondary with other respiratory diseases (C group). PATIENTS Forty-three cases (45 episodes) with mediastinal emphysema treated at Kawasaki Medical School Kawasaki Hospital between April 1985 and March 2000 (A group: 17 cases, B group: 17 cases, C group: 9 cases). RESULTS The average ages of the A and B groups were of little significance. Most of the patients in the A group were males with a thin body. Three patients in the A group had episodes of pneumothorax or mediastinal emphysema in their past history. Five patients in the A group had Hamman's sign on physical examination. In all of the patients in the C group, mediastinal emphysema was accompanied by subcutaneous emphysema, whereas only eight patients in the A group had subcutaneous emphysema. The prognosis was good for A and B groups because the mediastinal emphysema disappeared within 10 days, but was poor in the C group because its disappearance was very late compared with that in the other two groups and skin incision was required in three patients in the C group due to severe subcutaneous emphysema. CONCLUSIONS We suggest that the existance and kind of underlying diseases significantly affect the method of treatment and the prognosis.