覚醒剤使用者に発症した右心系感染性心内膜炎の1例

A case of right-sided infective endocarditis in a drug addict

　症例は49歳の男性。約1年前から覚醒剤の静脈注射を開始した。その2ヵ月後より悪寒と発熱が頻回に出現し，半年後には肺炎で他院に入院した。しかしその後も悪寒と発熱が続くため，精査目的に当院に入院した。

　入院時，著明な炎症反応と肝腫大，肝機能障害を認めた。血液培養からCampylobacter fetusを検出し，心エコー図検査で三尖弁前尖に沈贅を検出した。以上より，覚醒剤使用による三尖弁単独の感染性心内膜炎と急性肝炎の合併と診断した。また肺血流シンチで右下肺野に欠損を認め，前医での肺炎は疣贅の遊離による肺塞栓症と考えられた。抗生物質の投与により解熱し，炎症反応の消退と疣贅の著明な縮小と輝度の亢進を認めた。

　本邦においては覚醒剤使用者による感染性心内膜炎やCampylobacter fetusによる心内膜炎は本例がそれぞれ5例目と非常に稀であり，興味ある症例と考え若干の文献的考察を加え報告する。

A 49-year-old man was admitted to Mitsui Me-morial Hospital because of fever of unknown origin. Since one year ago, he had often used intravenous narcotic drugs. Ten months before his admission, he had his first experience of fever and a chill. Four months later, he was admitted to a hospital under the diagnosis of pneumonia and he was treated successfully. After his discharge, he began to use drugs again, which resulted in the repetition of fever and chills during four months prior to his admission to our hospital.

On admission, physical findings concerning the pa-tient were unremarkable, except for mild hepatome-galy. ECG and chest X-ray were normal. Labora-tory data revealed marked inflammatory changes and severe liver injury. Blood culture disclosed Cam-pylobacter fetus and two dimensional echocardio-graphy showed a large vegetation on the anterior tricuspid valve. He was diagnosed as isolated tricu-spid infective endocarditis accompanied with acute hepatitis due to drug abuse. Moreover pulmonary perfusion scintigraphy showed decreased perfusion in the right lower lung field, which suggested that pneumonia of six months ago was due to septic pul-monary emboli from the infected tricuspid valve. The combinated antibiotics therapy was successful. By the follow-up echocardiographic studies, the size of vegetation was observed to decrease progressi-vely.