Diffuse alveolar damage in patients with dermatomyositis: a six-case series.

The clinical course of diffuse alveolar damage (DAD) was studied in six consecutive cases of dermatomyositis (DM) based on our hospital records over 8 years. Three patients had severe myopathy at presentation, and the other three patients showed clinically amyopathic DM (CADM). Interstitial pneumonia in all patients developed shortly after they manifested DM. DAD in five deceased patients, which was proven pathologically, did not respond to steroid therapy combined with cyclosporine or tacrolimus. Of these, two patients began receiving combination therapy before suffering respiratory symptoms, and one of them had elevated serum Krebs von der Lungen-6 (KL-6) levels before visible abnormalities appeared on a plain chest X-ray. Only one patient with CADM survived; this patient received intravenously administered pulse cyclophosphamide (IVCY) therapy intravenously for DAD from the early stage. Delayed adjunctive IVCY was ineffective for progressed DAD in the remaining five patients. Elevated serum ferritin levels were observed in all four patients examined and might have predicted the lethal DAD, as in a previous report. In conclusion, promptly beginning IVCY therapy may be beneficial for patients with DM and interstitial pneumonia who show elevated serum levels of ferritin or KL-6 with minimal pulmonary abnormalities.