小児における孤立性天然肺動脈弁心内膜炎：限られたリソースでの診断および治療上の課題の克服

Isolated native pulmonary valve endocarditis (INPVE) is a rare form of infective endocarditis, accounting for <2% of cases. It typically affects the individuals with predisposing factors, including congenital heart defects, intravenous drug use, or indwelling catheters. Pediatric cases without such risk factors are extremely uncommon. Diagnosis is often delayed due to nonspecific symptoms that resemble pneumonia, sepsis, or heart failure and is further complicated by culture-negative results from prior antibiotic use. We present the case of a previously healthy 9-year-old boy with prolonged fever, respiratory distress, and malnutrition. Initial treatment for pneumonia was ineffective, prompting further workup that revealed pulmonary valve vegetations, functional valve stenosis and insufficiency, and right heart dilation. Blood cultures were negative, but empirical antibiotic therapy led to clinical improvement. This case underscores the need for early suspicion, timely imaging, and empirical treatment in suspected INPVE, especially in the resource-limited settings where diagnostic and surgical options are restricted.