Internal Medicine

0521779407-10 CUNY1086/Karliner 0 521 77940 7 June 7, 2007 18:40

830 Infective Endocarditis

glomerulonephritis; pulmonary infiltrates on CXR with right-sided

endocarditis and embolization to the lungs; conduction abnormal-

ities on EKG suggest myocardial abscess

■Definitive diagnosis made by blood culture; 3 blood cultures

obtained over 24 hours (in acutely ill, 3 blood cultures at least 1

hour apart) positive in over 95%; negative cultures due causes listed

above

If culture negative: serology, valve tissue PCR, or histopathology

(if early surgery) may aid diagnosis.

■Echocardiography helpful in establishing diagnosis and defining

valve involved; transthoracic echo positive in 60%; transesophageal

echo positive in 90% (especially good for pulmonic valve and pros-

thetic valve endocarditis and detecting myocardial abscesses

■Duke criteria for clinical diagnosis; probable endocarditis (80%

likelihood) if 2 major criteria, 1 major and 3 minor criteria or 5

minor criteria; possible endocarditis if 1 major and 1 minor crite-

ria or 3 minor criteria; major criteria=(1) two separate positive

blood culture for organisms that typically cause endocarditis (2) evi-

dence of endocardial involvement pathologically or by echo (vege-

tation, abscess or dehiscence of prosthetic valve) (3) new regurgitant

murmur; minor criteria=(1) predisposing heart disease or IV drug

use (2) fever greater than 38 (3) vascular phenomenon (systemic or

pulmonary embolization (4) immunologic phenomenon (glomeru-

lonephritis, Osler node, Roth spot) and (5) positive blood cultures,

but not meeting the major criteria

differential diagnosis

■Nonspecific clinical manifestations similar to many febrile illnesses

including other infections, collagen vascular disease, cancer; con-

sider in anyone with fever and heart murmur, a prosthetic valve and

fever, any young person with an unexplained neurologic event and

in IV drug users with fever

management

■Establish diagnosis with blood cultures; in acutely ill, do not delay

therapy to obtain multiple blood cultures; in nonacute patients on

antibiotics, reasonable to withhold antibiotics 3–4 days to obtain

cultures off therapy

■Anticoagulation contraindicated in native valve endocarditis; in

prosthetic valve endocarditis, anticoagulation continued unless

there has been an intracerebral bleed