Diagnosis of infective endocarditis

摘要

Since Osier's description of the classical signs-beloved of medical students, postgraduates, and their examiners-infective endocarditis has remained a clinical diagnosis. But despite improved preventive strategies, rational prescribing of antibiotics, advances in imaging, and increasing use of lifesaving cardiac surgery at an early stage the incidence and mortality of the condition remain high. Current estimates suggest an incidence of 1.7-6.2 per 100 000 person years in the United States. Mortality varies according to the infecting organism (viridans streptococci 4-16%, Staphylocoaus aureus 25-47%, fungal infections over 50%) and is higher when infection affects a prosthetic valve or is complicated by congestive heart failure, abscess formation, or a neurological event. Infective endocarditis often presents in an occult fashion, and early diagnosis depends on a high index of clinical suspicion especially in patients with congenital heart disease, prosthetic valves, or previous infective endocarditis. Sadly, clinical experience shows that the sickest patients are often referred late for imaging, specialist care, or surgery, even when the diagnosis has been clear for days or weeks-albeit in hindsight. Conversely, echocardiography departments are universally swamped with imaging requests for patients in whom the diagnosis is unlikely.