[Interstitial pneumonia complicating amyopathic dermatomyositis: a case report].

Amyopathic dermatomyositis (ADM) is a clinical subtype of dermatomyositis, characterized by the absence of motor weakness and the presence of normal muscle enzyme levels. ADM is sometimes accompanied by neoplasm or interstitial pneumonia that shows a rapid progressive course both of them are associated with a poor prognosis. A 56-year-old woman with no medical history was referred to the department of medicine because of arthralgia with a remarkable weight loss. She also complained of rapidly progressive dyspnea, cough and photosensitivity. Physical examination on admission showed scaly erythema on the dorsum of the hands (Gottron sign) and periorbital edema with a purplish appearance (heliotropic rash), arthritis, but no muscle weakness. Auscultation of the chest identified audible fine crackles on the lower aspects of both lungs. Results of laboratory findings on admission revealed a lymphopenia. The serum creatine kinase and serum lactate dehydrogenase concentration were normal. IRM muscle and electromyography were normal. Antinuclear antibody was positive 1:80 and anti-Jo-1 antibody and other autoantibodies to specific antigens were all negative. High resolution computed tomographic chest scans also revealed diffuse ground-glass opacities in both lungs with basilar predominance. Arterial blood gas analysis revealed hypoxia and hypocapnia. LBA was not performed because of the deterioration of respiratory symptoms. There was no neoplasm associated. The diagnosis of ADM complicated with ADM rapidly progressive interstitial pneumonia was made. Despite of IV methylprednisolone pulse therapy (1g*day-1 for 3 days) and cyclophosphamide, she died by respiratory failure.