Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ KEY FEATURES +++ ESSENTIALS OF DIAGNOSIS ++ Clinical features: fever, new valvular regurgitation, embolization, immune complexes, predisposing condition. ≥ Two positive blood cultures with a typical microbe Characteristic cardiac lesions on echocardiography or histology +++ GENERAL CONSIDERATIONS ++ Infective endocarditis represents an endothelial infection that usually occurs at sites of endothelial damage in blood vessels and is rare Infection of cardiac valve endocardium is not rare and can afflict normal valves, but preexisting valve disease as a substrate is more common. Valve infection probably begins with minor trauma, which would explain the observation that the valves with the highest force necessary to close the valve are the most commonly affected; in rank order: mitral, aortic, tricuspid, pulmonic. Also, infection usually starts at the closure line of the valves Minor trauma may form a microscopic thrombus on the leaflet surface, which forms the nidus for infection For the nidus to become infected, bacteria must enter the bloodstream in sufficient numbers from a break in the epidermal or mucosal surfaces of the body As the vegetation grows, regurgitation of the affected valve almost always occurs due to destruction, scarring, or retraction of the leaflet Occasionally, chordal involvement results in rupture or erosion of the leaflet to perforation, both of which can cause sudden severe atrioventricular valve regurgitation Very large vegetations rarely can obstruct the valve orifice Embolization of vegetations can result in damage to other organs from ischemia or remote infection Invasion of the valve annulus by the organisms can lead to abscesses and fistulas Infection of arterial walls due to vegetation embolization can lead to aneurysm formation and rupture, which can be devastating in the central nervous system +++ CLINICAL PRESENTATION +++ SYMPTOMS AND SIGNS ++ Common symptoms: fever, chills, weakness, dyspnea Less common symptoms: diaphoresis, weight loss, cough, stroke, rash, nausea/vomiting, headache, chest pain, myalgias/arthralgias Unusual symptoms: abdominal pain, delirium/coma, hemoptysis, back pain +++ PHYSICAL EXAM FINDINGS ++ Common findings: fever, heart murmur, skin lesions or emboli, petechiae Less common findings: Osler’s node, Janeway lesion, splinter hemorrhages, splenomegaly, stroke, heart failure, pneumonia, meningitis Unusual findings: new or changing murmur, retinal lesions (Roth spots), renal failure, blue toe syndrome Splenomegaly +++ DIFFERENTIAL DIAGNOSIS ++ Fever due to other causes Sepsis not due to infective endocarditis Valvular lesions on echocardiography that resemble infective vegetations: myxomatous valves, Libman-Sacks vegetations, marantic vegetations, papillary fibroelastomas, Lambl excrescences, nodules of Arantius (aortic valve) +++ DIAGNOSTIC EVALUATION +++ LABORATORY TESTS ++ Blood cultures: 3 from separate venipunctures over 24 hours Serologic testing for organisms such as Histoplasma, Q fever, Brucella, Bartonella Rheumatoid factor may be falsely positive Leukocytosis, elevated gamma globulins, elevated erythrocyte sedimentation rate, anemia +++ ELECTROCARDIOGRAPHY ++ Sinus ... Your MyAccess profile is currently affiliated with '[InstitutionA]' and is in the process of switching affiliations to '[InstitutionB]'. Please click ‘Continue’ to continue the affiliation switch, otherwise click ‘Cancel’ to cancel signing in. Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Username Error: Please enter User Name Password Error: Please enter Password Forgot Username? Forgot Password? Sign in via OpenAthens Sign in via Shibboleth