A. Phadke

July 2, 2010

For the Peds Clerk Website

Infectious Endocarditis

Epidemiology:

- Incidence of endocarditis estimated as 2-6 cases/100,000 person years

- 90% of endocarditis occurs in patients with pre-existing heart disease

- Worldwide, condition that most predisposes individuals to endocarditis is rheumatic heart disease; nationwide, it is mitral valve prolapse

- Endocarditis continues to have a high mortality, estimated at 10-20% among hospitalized patients

- Greatest morbidity occurs among those with recent cardiac prostheses, status-post heart transplant, or prior endocarditis

Pathogenesis

- Step 1: Formation of non-bacterial thrombotic embolus (vegetation)

o Turbulent flow from acquired or congenital heart disease traumatizes endothelium

o Traumitized endothelium serves as a nidus for fibrin and platelet deposition

- Step 2: Pathogen seeds blood; generally occurs via trauma to a mucosal surface from such daily activities as teeth brushing or chewing, or invasive activities like dental, GI, or GU procedures

- Step 3: Pathogen adheres to fibrin-laden endothelium or device

o Gram-positive cocci (Staph, Strep) most common pathogens

o Gram-negative bacteria (HACEK organisms) and fungi (Candida, Aspergillus) can also adhere

- Step 4: Pathogen promotes fibrin deposition

o Micro-organism stimulates more fibrin deposition on pre-exisiting aseptic vegetation

o Creates secluded area within which pathogen can proliferate

Sequelae

- Valvular damage: Pathogen destroys valves à cause regurgitation and possibly even heart failure

- Emboli: Septic emboli travel to lung, brain, kidney, or extremities and cause local infection and ischemia/infarction

- Immune-mediated: Circulating immune complexes can possibly mediate glomerulonephritis or vasculitis

Clinical Presentation:

- Overview:

o Non-specific signs – fever, myalgia, arthralgia, headache, malaise, anorexia, weight loss – are common

o Classic signs – Roth spots, Janeway lesions, Osler nodes, and splinter hemorrhage – are rare in children

- Making the diagnosis:

o Pathologic evidence of intracardiac or embolized vegetation or intracardiac abscess OR

o 2 major, 1 major and 3 minor, or 5 minor of the Duke Criteria:

Duke Criteria

Major Criteria

● Positive blood culture*

● Positive echocardiogram (vegetation, paravalvular abscess, or valve dehiscence after surgery)

● New valvular regurgitation (by auscultation, not echocardiogram)

Minor Criteria

● Predisposing heart condition (including prior IE)

● Injection drug use

● Fever (temperature >100.4°F [38°C])

● Major arterial emboli

● Septic pulmonary infarcts

● Mycotic aneurysm

● Intracranial hemorrhage

● Conjunctival hemorrhage

● Janeway lesions (painless hemorrhagic lesions on palms and soles)

● Glomerulonephritis

● Osler nodes (painful lesions at fingertips)

● Roth spots (retinal hemorrhages)

● Positive rheumatoid factor

● Single positive blood culture

● Serologic evidence of active infection with an “organism consistent with IE”

Note: Splinter hemorrhagees and erythrocyte sedimention rate are not criteria. Also, there are no “minor” echo criteria, ie, valvular

regurgitation alone is not a criterion.

*A positive blood culture is a major criterion when 1) there is growth on two occasions of a microorganism “typical for” IE (eg, Streptococcus viridans,

Staphylococcus aureus, or enterococcus), OR 2) there are “persistently postiive” blood cultures (two positive cultures from samples 12 h apart or three positive

cultures drawn 1 h apart) of a microorganism “consistent with IE,” such as S epidermidis, OR 3) Coxiella burnetii (Q fever) grows from a single blood culture

or there is serologic evidence of C burnetii (IgG titer _1:800).

From Li JS, Sexton DJ, Mick N, et al. Proposed modifications to the Duke Criteria for the diagnosis of infective endocarditis. Clin Infect Dis.

2000;30:633–638. Used with permission from the University of Chicago Press.

- While transesophageal echo recommended in adults, transthoracic echo is fine in children

Treatment

- If blood cultures have not come back and need to begin treatment, generally begin empiric coverage against staph and strep with penicillin or ampicillin plus gent for 4-6 weeks; IV treatment most effective

- Surgery indicated in those with persistent blood cultures after two weeks of appropriate treatment, fungal vegetations, abscess formation, worsening heart failure, or systemic emboli

Prophylaxis

In 2007, the American Heart Association (AHA) revised its criteria for bacterial prophylaxis against endocarditis. Current guidelines state that only those individuals with the following conditions require one dose antibiotic prophylaxis prior to undergoing dental procedures:

1. Prosthetic cardiac valve or prosthetic material used for cardiac valve repair

2. Previous infectious endocarditis

3. Of those with congenital heart disease (CHD), those with 

a. Unrepaired cyanotic CHD, including palliative shunts and conduits    

b. Completely repaired congenital heart defect with prosthetic material or device for the first 6 months after the procedure

c. Repaired CHD with residual defects at the site or adjacent to the site of a prosthetic patch or prosthetic device

4. Cardiac transplantation recipients who develop cardiac valvulopathy

The rationale for the revised criteria is that the majority of endocarditis in non-IV drug users is caused by transient bacteremia resulting from daily activities, such as chewing food, flossing, and brushing teeth, rather than semi-annual, invasive dental procedures. However, by the reasoning of the AHA, in the aforementioned groups, the risk of serious adverse outcome from endocarditis is so great as to warrant prophylaxis.

Sources

1) Habib, G. et al. (Jan 2006).  Management of infective endocarditis. Heart. Vol 92(1). Retrieved from http://heart.bmj.com

2) Hoyer, A. & M. S. (Nov 2005). Infective Endocarditis. Pediatrics in Review. Vol.26 (11). Retrieved from www.pedsinreview.org

3) Keys, Thomas. Infective Endocarditis. Cleveland Clinic Publications. Retrieved from www.clevelandclinicmeded.com

4) Wilson, W et al. (2007). Prevention of Infective Endocarditis. Guidelines From the American Heart Association: A Guideline From the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Circulation. Vol. 116. Retrieved from http://circ.ahajournals.org/

5) Wu, I & J.O. (Feb 2008). Recurrent Bacterial Endocarditis Complicated by Acute Kidney Injury. Hospital Physician. Retrieved from http://www.turner-white.com