慢性心筋炎の急性増悪を合併した多発性筋炎の1剖検例

An Autopsy Case of Polymyositis with Exacerbation of Chronic Myocarditis

要旨　症例は38歳男性。主訴は全身倦怠感。2000年11月頃より，全身倦怠感，四肢近位筋の筋力低下，乾性咳嗽が出現した。筋原性酵素の上昇と胸部CTにて間質性陰影を認めた。これらの症状は持続し，2001年1月からは労作時呼吸困難も発現し，改善がないため同年4月に当科入院した。精査にて軽度の間質性肺炎を伴う軽症の多発性筋炎と診断し，ステロイドパルス療法を施行した。血中CK値は低下したが，ステロイドパルス療法後に，急性の循環不全に至り死亡した。剖検時の病理学的所見から多発性筋炎に伴う慢性心筋炎の増悪と考えられた。多発性筋炎では致死的な心病変をきたすことが稀にあり，重要な合併症として常に念頭におく必要がある。

A 38-year-old man had sufferd from general fatigue, mild weakness of proximal muscles, and dry cough in November, 2000. Serum levels of muscle enzymes were elevated. Computed tomography of the chest revealed reticular appearance in the bilateral dorsal lung areas. He did not show any improvement, therefore he was referred to our hospital in April, 2001. He was diagonosed as mild polymyositis with mild interstitial pneumonia. He was treated intravenously with methylprednisolone pulse therapy. During the pulse therapy serum level of creatine kinase was decreased, but he died because of acute pump failure of the heart. The cause of the heart failure could be an exacerbation of chronic myocarditis associated with polymyositis and it was comfirmed by autopsy findings. When a patient with mild polymyositis complaines of general fatigue, myocarditis should be carefully evaluated because of the high risk of death.