[A case of dermatomyositis which rapidly developed to respiratory failure in the presence of pneumomediastinum].

A 49-year-old woman was admitted in February 1987, with a six-month history of joint pain, maculopapular and erythematous rash, proximal muscle weakness and a two-month history of skin ulceration and dyspnea on exertion. Physical examination showed Gottron's papules on her fingers and a faint heliotrope rash. Biopsy of erythematous skin lesions on the shoulder and the back of the hand revealed perivascular inflammatory cell infiltration and tiny ulcerative lesions of the cutaneous tissue. Biopsy of the right quadriceps muscle showed type II fiber atrophy and slight perivascular lymphocytic infiltrate, whereas serum CPK level was within normal range. Chest X-ray film showed granular infiltrates in both lower lung fields. Based on the current findings the case was diagnosed as dermatomyositis associated with interstitial pneumonia. The administration of prednisolone, 30 mg/day resulted in the improvement of the skin lesions and muscle weakness, while the intensity of lung infiltrates was little affected. Three months after steroid therapy, the patient was readmitted because of increasing dyspnea on exertion and multiple skin ulcers. Chest X-ray revealed a small amount of gas in the mediastinum, in addition to slight deterioration of interstitial lung disease. In spite of various treatments for pneumomediastinum, including bed rest, administration of analgesics and oxygen inhalation, it developed rapidly, complicated severe subcutaneous emphysema and right-sided pneumothorax. Although high-dose prednisolone therapy and mediastinal drainage were performed, the pneumomediastinum was not resolved and she died from respiratory failure. At autopsy, predominant histological features of the lungs were acute interstitial pneumonia with hyaline membrane and edematous granulation formation in the alveoli.(ABSTRACT TRUNCATED AT 250 WORDS)