Infective endocarditis
Infective endocarditis is microbial infection of the endocardium, usually a heart valve, producing vegetations that cause valve destruction, embolism, and systemic infection. Diagnosis uses the modified Duke criteria combining blood cultures and echocardiography, and treatment is prolonged targeted intravenous antibiotics with surgery for complications.
- Topic reviewThe full article, organized the way the exam asks it.
- ABIM-format MCQsVignettes with an explanation for every wrong answer.
- Key factsThe numbers and thresholds worth memorizing, up front.
- AI tutorMedBrain answers the question you're stuck on.
What this article covers
- Overview
Definition: infective endocarditis is microbial infection of the endocardial surface, most often a native or prosthetic heart valve, producing vegetations of organisms, platelets, and fibrin.
- Epidemiology
Staphylococcus aureus is now the leading cause in much of the world.
- Risk factors
Structural valve disease: rheumatic, degenerative, congenital, and prosthetic valves.
- Pathophysiology
Endothelial injury and thrombus: damaged endocardium forms a sterile platelet-fibrin nidus.
- Clinical features
Fever and constitutional symptoms (malaise, night sweats, weight loss).
- Differential diagnosis
Nonbacterial thrombotic endocarditis: sterile platelet-fibrin vegetations in malignancy or autoimmune disease, distinguished by persistently negative blood cultures and no systemic infection (Nonbacterial thrombotic endocarditis).
- Diagnosis
Establish with the modified Duke criteria integrating blood culture results and echocardiographic evidence: the diagnostic basis is the combination of major criteria (typical organisms on…
- Management
First-line, start targeted prolonged intravenous antibiotics after cultures: begin pathogen-directed intravenous therapy (empiric therapy such as vancomycin 15 to 20 mg/kg IV every 8 to 12 hours plus…
- Complications
Valve destruction with acute regurgitation and heart failure.
- Prognosis
Depends on the organism, valve, and complications; S.
- Prevention
Antibiotic prophylaxis before high-risk dental procedures in high-risk patients (prosthetic valves, prior endocarditis, certain congenital disease): amoxicillin 2 g PO as a single dose 30 to 60 minutes before the procedure.
Read the whole article
Subscribing to Internal Medicine opens every article, the full question bank and MedBrain, on the web, iPhone and Android.
Related articles
- Prosthetic valve endocarditis
Prosthetic valve endocarditis is infection of a prosthetic heart valve, classified as early or late by time from surgery, and it is more aggressive and harder to treat than native valve disease. It commonly causes perivalvular abscess and dehiscence, requires transesophageal echocardiography and prolonged antibiotics, and often needs surgery.
- Mitral regurgitation
Mitral regurgitation is systolic backflow from the left ventricle into the left atrium, classified as primary (valve disease) or secondary (ventricular or annular disease). Chronic disease causes volume overload with an apical holosystolic murmur, while acute severe regurgitation causes pulmonary edema; severe primary disease is treated with valve repair or replacement.
- Aortic regurgitation
Aortic regurgitation is diastolic backflow of blood from the aorta into the left ventricle from valve or aortic root disease. Chronic disease causes volume overload with a wide pulse pressure and a decrescendo diastolic murmur, while acute severe regurgitation is a surgical emergency; severe symptomatic or decompensating disease is treated with valve replacement.
- Nonbacterial thrombotic endocarditis
Nonbacterial thrombotic endocarditis (marantic endocarditis) is sterile platelet-fibrin vegetations on cardiac valves associated with malignancy and autoimmune disease, notably antiphospholipid syndrome and lupus (Libman-Sacks). It rarely destroys valves but embolizes readily, so treatment is anticoagulation and management of the underlying disease.
- Rheumatic heart disease
Rheumatic heart disease is chronic valvular damage following acute rheumatic fever, an autoimmune sequela of group A streptococcal pharyngitis. It predominantly scars the mitral and aortic valves, causing stenosis and regurgitation years later; management is secondary antibiotic prophylaxis, treatment of valve lesions, and prevention of recurrent rheumatic fever.