INFECTIVE ENDOCARDITIS

CLASSIFICATION

OLD•Subacute bacterial endocarditis•Acute bacterial endocarditis

NEW•Native valve endocarditis•Prosthetic valve endocarditis•Endocarditis in injection drug users•Nosocromial endocarditis(not includued everywhere)

PATHOGENESIS

• Alteration of the valvular endothelium leading to deposition of platelets and fibrin•Bacteremia with seeding of non-bacterial thrombotic vegetation(NBTE)•Adherence and growth, further platelet and fibrin deposition•Extension to other structures

- Papillary muscle, aortic valve ring abscess, conduction system

•Intravenous drug abuse•Artificial heart valves and pacemakers•Acquired heart defects•Calcific aortic stenosis•Mitral valve prolapse with regurgitation•Congenital heart defects•Intravascular catheters

RISK FACTORS

•Staphylococcus aureus(30-40%)•Viridans group streptococci(18%)•Enterococci (11%)•Coagulase-negative staphylococci (11%)•Streptococcus bovis(7%)•Other streptococci (5%)•Non-HACEK Gram negatives(2%)•HACEK organisms(2%)•Fungi(2%)•Culture negative(2-20%)

MICROBIOLOGY

•Fever •Heart murmur•Nonspecific signs – petechiae, subungal or “splinter” hemorrhages, clubbing, splenomegaly, neurologic changes•More specific signs - Osler’s Nodes, Janeway lesions, and Roth Spots

SIGNS

Petechiae

Photo credit, Josh Fierer, M.D. medicine.ucsd.edu/clinicalimg/ Eye-Petechiae.html

Harden Library for the Health Scienceswww.lib.uiowa.edu/ hardin/md/cdc/3184.html

1. Nonspecific2. Often located on extremities

or mucous membranesdermatology.about.com/.../ blpetechiaephoto.htm

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

American College of Rheumatologywebrheum.bham.ac.uk/.../ default/pages/3b5.htm

www.meddean.luc.edu/.../ Hand10/Hand10dx.html

Janeway Lesions

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

DIAGNOSIS

Blood CulturesMinimum of three blood cultures1

Three separate venipuncture sitesObtain 10-20mL in adults and 0.5-5mL in children2

Positive ResultTypical organisms present in at least 2 separate samplesPersistently positive blood culture (atypical organisms)

Two positive blood cultures obtained at least 12 hours apartThree or a more positive blood cultures in which the first and last samples were collected at least one hour apart

BLOOD CULTURE

Chest x-ray Look for multiple focal infiltrates and calcification of heart valves

EKGRarely diagnosticLook for evidence of ischemia, conduction delay, and arrhythmias

Echocardiography

IMAGING

Transthoracic echocardiography (TTE)First line if suspected IENative valves

Transesophageal echocardiography (TEE)Prosthetic valvesIntracardiac complicationsInadequate TTE Fungal or S. aureus or bacteremia

INDICATIONS FOR ECHOCARDIOGRAPHY

CARDIAC COMPLICATIONS

•Vegetations on valve closure lines•Destruction and perforation of valve leaflets•Rupture of chordae tendinae, intraventricular septum, papillary muscles•Valve ring abscess•Myocardial abscess•Conduction abnormalities•Congestive heart failure

EXTRA CARDIAC COMPLICATIONS

KIDNEY•Immune complex glomerulonephritis•Emboli with infarction, abcess

AORTIC MYCOTIC ANEURYSM

CEREBRAL EMBOLISM•Infarction, abcess, mycotic aneurysm•Purulent/aseptic meningitis•Hemorrhage

SPLENIC ENLARGEMENT, INFARCTION

SEPTIC OR BLAND PULMONARY EMBOLISM

SKIN

BOWEL AND OTHER ORGAN EMBOLI’S