A 50-year-old man presents to the emergency room for a fever that has persisted for several days. He denies any history of intravenous drug use or any congenital heart disease. Physical exam reveals nailbed splinter hemorrhages, Osler nodes on his fingers, and Janeway lesions on his palms and soles. Heart auscultation reveals a new murmur. An echocardiogram shows vegetations on the mitral valve, and blood cultures that were drawn 12 hours apart were positive for Streptococcus bovis. Antibiotic therapy is started and he is scheduled for a colonoscopy.
Introduction
Clinical definition inflammation of the heart valve, typically secondary to infection. Epidemiology location mitral valve > tricuspid valve. Tricuspid valve disease is associated with intravenous (IV) drug use. Staphylococcus aureus, Pseudomonas, Candida. Risk factors rheumatic heart disease, IV drug use, immunosuppression, prosthetic heart valve, congenital heart disease. Etiology acute endocarditis Streptococcus pneumoniae, Streptococcus pyogenes, Neisseria gonorrhoeae, Staphylococcus aureus in IV drug users; large vegetations seen on valves. Subacute bacterial endocarditis is characterized by slower onset and less severe symptoms. Streptococcus bovis (gallolyticus) in the setting of colon cancer, Enterococcus in the setting of gastrointestinal/genitourinary procedures, Streptococcus viridans often a complication of dental procedures, makes dextrans which bind to fibrin-platelet aggregates on the heart valves, Staphylococcus epidermidis often in the setting of prosthetic valves, Candida albicans in IV drug users. Non-infectious endocarditis: Libman-Sacks endocarditis from systemic lupus erythematosus, mitral or aortic valve involvement; marantic endocarditis from metastatic cancer seeding to the valves, very poor prognosis. Pathogenesis endothelial damage on the surface of the cardiac valve can cause a thrombus to form; factors include turbulent blood flow that can damage the endothelium or deposition of fibrin-platelet aggregates on damaged endothelium; bacteria can then adhere to the thrombus; vegetations are caused by further deposition of fibrin and platelets. Prognosis often presents as fever of unknown origin; endocarditis prophylaxis may be required before dental procedures.
Presentation
Symptoms: persistent fever (the most common symptom), shortness of breath, systemic symptoms such as weakness, fever, and malaise.
Physical exam: new murmur on auscultation.
From emboli: Roth spots — retinal hemorrhages seen on fundoscopy; Janeway lesions — erythematous, non-tender macules on the palms or soles; nail bed splinter hemorrhages; Osler nodes — tender nodules on the fingers or toes; glomerulonephritis (from immune complex deposition).
Imaging
Echocardiography indication for all patients findings vegetations on valves
Evaluation
Labs: positive blood cultures drawn at least 12 hours apart, or multiple positive cultures (at least 3 of 4) with the first and last drawn at least 1 hour apart. Complete blood count shows anemia. Serum creatinine is checked to evaluate renal function (glomerulonephritis).
Making the diagnosis: based on clinical presentation and Duke criteria.
Pathologic criteria: culture of organism; histologic evidence of endocarditis from vegetation or intracardiac abscess.
Clinical criteria: one of the following — 2 major criteria, 1 major and 3 minor criteria, or 5 minor criteria.
If blood cultures are negative but echocardiography shows endocarditis, consider causes of Culture-Negative Endocarditis (CNE): Coxiella burnetii, Bartonella spp., HACEK organisms (Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella).
Differential:
Osteomyelitis — distinguishing factor: although this can present as fever of unknown origin, it typically lacks other findings of endocarditis and will not have vegetations on echocardiography.
Treatment
Management approach: Choice of antibiotics ultimately depends on the causative agent and susceptibility, as well as the presence of prosthetic material in the heart. All antibiotics should be given intravenously.
Medical
Vancomycin plus ceftriaxone or gentamicin.
Indications: For patients with no prosthetic valve; empiric antibiotic therapy.
Vancomycin plus gentamicin and rifampin.
Indications: For patients with a prosthetic valve; empiric antibiotic therapy.
Operative
Surgical valve replacement.
Indications: Heart failure, patients who are refractory to medical therapy, abscess formation, conduction disturbances.
Complications:
Cardiac complications — perivalvular abscess, arrhythmias, heart failure.
Neurologic complications — stroke.