Internal Medicine

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

Infective Endocarditis 829

Infective Endocarditis.................................

RICHARD A. JACOBS, MD, PhD

history & physical

History

■Usually, but not always (ie, IV drug users), an underlying abnormality

predisposing to infection – valvular disease (rheumatic heart disease,

mitral valve prolapse), damage to endothelium from regurgitant jet

flow or congenital abnormalities (VSD, patent ductus)

■Etiology depends on clinical setting: Native valve endocarditis due

to viridans streptococci, S. aureus and enterococci; prosthetic valve

endocarditis within 2 months of surgery (early infection) due to

S. epidermidis (and other coagulase-negative staphylococci), S.

aureus, Gram negative bacilli; late infections (greater than 2 months

post-operatively) similar to native valve endocarditis; endocarditis

in IV drug users caused predominantly by S. aureus; culture nega-

tive endocarditis due to previous administration of antibiotics, fungi

(blood cultures positive in only 50% of cases), slow growing organ-

isms such as the HACEK organisms and Brucella, organisms that

require special media for growth such as Legionella, Bartonella, and

nutritionally variant streptococci, and organisms that do not grow

on conventional media such as Coxiella burnetii (Q fever)

Signs & Symptoms

■Virulent organisms (S. aureus) usually present acutely with rapidly

progressive infection, tissue destruction and systemic emboli,

although more indolent presentation (especially IV drug users with

tricuspid infection) can occur; less virulent organisms (streptococci,

enterococci, fungi, HACEK organisms)present most often with a sub-

acute course

■Presenting symptoms often nonspecific – fever, chills, malaise,

arthralgias, back pain; peripheral embolization manifest as stroke or

abdominal pain (splenic embolization); fever (90%), heart murmur

(80–90%), splenomegaly (40%) and peripheral manifestations such

as petechiae, splinter hemorrhages, Osler nodes, Janeway lesions

and Roth spots occur in 10–40%

tests

■Elevated WBCs in acute disease; anemia with subacute disease;

hematuria from embolization to kidneys or immune-mediated