INFECTIVE ENDOCARDITI

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ByLIKHILA ABRAHAM

Definition Infective endocarditis (IE) is defined as an infection of the endocardial surface of the heart, which may include one or more heart valves, the mural endocardium, or a septal defect. Its intracardiac effects include severe valvular insufficiency, which may lead to intractable congestive heart failure and myocardial abscesses. If left untreated, IE is generally fatal.(medscape)

Infective endocarditis (IE) is a microbial infection of the endothelial surface of the heart or iatrogenic foreign bodies like prosthetic valves or other intracardiac devices

Types Native valve endocarditis (NVE), acute and subacuteProsthetic valve endocarditis (PVE),[10] early and lateIntravenous drug abuse (IVDA) endocarditis

•Risk factors •Structural heart disease–Rheumatic, congenital, aging–Prosthetic heart valves•Injected drug use•Invasive procedures (Intracardiac pacemaker, ICD , AV Fistula)•Indwelling vascular devices•Other infection with bacteremia (e.g. pneumonia, meningitis)•Immunocompromised states•History of infective endocarditis

BacterialStaphylococcus aureus followed by Streptococci of the viridans group and Coagulase negativ Staphylococci are the three most common organisms responsible for infective endocarditis. Other Streptococci and Enterococci are also a frequent cause of infective endocarditis. 

Fungal and Viral

Candida albicans, a yeast, is associated with endocarditis in IV drug users and immunocompromised patients. Other fungi demonstrated to cause endocarditis are Histoplasma capsulatum and Aspergillus

HACEK organismsHemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella

Nonbacterial Thrombotic Endocarditis

Endothelial injuryHypercoagulable state

Lesions seen at coaptation points of valves

Atrial surface mitral/tricuspidVentricular surface aortic/pulmonic

Clinical features

•Symptoms–Fever, sweats, chills–Anorexia, malaise, weight loss•Signs–Anemia (normochromic, normocytic)–Splenomegaly–Microscopic hematuria, proteinuria–New or changing heart murmur, CHF–Embolic or immunologic dermatologic signs–Hypergammaglobulinemia, elevated ESR, CRP, RF

Cardiac Pathologic Changes Vegetations on valve closure lines Destruction and perforation of valve leaflet Rupture of chordae tendinae,

intraventricular septum, papillary muscles Valve ring abscess Myocardial abscess Conduction abnormalities

S. Aureus mitral valve vegetation, anterior leaflet

Pathologic Changes

Kidney◦ Immune complex glomerulonephritis◦ Emboli with infarction, abscess

Aortic mycotic aneurysms

Pathologic Changes

Splenic enlargement, infarction Septic or bland pulmonary embolism Skin

◦ Petechiae◦ Osler nodes: diffuse infiltrate of neutrophils,

and monocytes in the dermal vessels with immune complex deposition. Tender and erythematous

◦ Janeway lesions: septic emboli with bacteria, neutrophils and S/C hemorrhage and necrosis. Blanching and non-tender. Palms and soles

Splinter Hemorrhages

1. Nonspecific2. Nonblanching3. Linear reddish-brown lesions found under the nail bed4. Usually do NOT extend the entire length of the nail

Osler’s Nodes

1. More specific2. Painful and erythematous nodules3. Located on pulp of fingers and toes4. More common in subacute IE

Janeway Lesions

1. More specific2. Erythematous, blanching macules 3. Nonpainful4. Located on palms and soles

Roth spots

Modified Duke Criteria

Two major criteria, OR One major and three minor criteria, ORFive minor criteria allows a clinicaldiagnosis of definite endocarditis.

Other tests

Electrocardiogram◦ Conduction delays◦ Ischemia or infarction

Chest X-ray◦ Septic emboli in right-sided IE◦ Valve calcification◦ CHF

Antimicrobial Therapy

Blood culture become sterile within 2 days Fever resolves in 4 to 7 days If fever persists despite 7 days of antibiotics

evaluate for paravalvular or extracardiac abscess

Combination therapy most important for◦ Shorter course regimens◦ Enterococcal endocarditis◦ Prosthetic valve infections

Streptococci susceptible to pencillin

NVE

Fungal◦ Amphotericin◦ Fluconazole◦ Caspofungin, little data◦ Surgery usually necessary 1-2 weeks into

treatment