Infective Endocarditis

Question 1

Infective Endocarditis

microbial infection of the inner lining of heart or heart valves.

Mortality 40%

Predisposing conditions:

#1 mitral valve prolapse, aortic valve disease, congenital heart disease, prosthetic valve, IV drug abuse (others: rheumatic heart dz, SLE)

Causative organisms:

#1 streptococci, staphylococci, enterococci (first 2 in oral cavity)

Answer 1

1 cause of death: heart failure due to valvular dysfunc

Pathophysiology:

1. Injury (high flow) to valve leaflet next to defect/prosthesis
2. Fibrin/platelet aggreg (nonbacterial thrombotic endocarditis)
3. Transient bacteremia (seeding)
4. More platelet/fibrin sequester & protect bacteria
5. Continuous bacteremia (shed into bloodstream) + embolism of vegetation fragments

Complications:

stroke, MI, pulmonary embolism, peripheral metastatic abscesses, renal dysfunction (immune complex glomerulonephritis)

Question 2

Sign and Symptoms

• Fever, heart murmur, positive blood culture

Latency Period

• 80% of cases develop within 2 weeks of exposure
• many cases blamed on dental procedure fell outside that range

Answer 2

Medical treatment:

Penicillin + Gentamicin

Vancomycin (if allergic to PenVK)

Surgery of if sig. dmg.

Survival 60% (mortality 40%)

Question 3

AHA Guideline (Lockhart):

1. IE more likely from freq exposure to random bacteremia from daily activities than dental procedure
2. Abx prophy (even if 100% effective) may prevent exceeding small #cases of IE
3. Abx adverse events outweighs benefits
4. Maintenance of optimal oral health reduces bacteremia

Answer 3

Dental Abx prophy recommended (highest risk of adverse outcomes)

1. Previous IE
2. Cardiac transplant (who develop cardiac valvulopathy)
3. Prosthetic heart valve
4. Congenital heart disease
   
   • Unrepaired CHD
   • Completely repaired CHD with prosthetic material/device (1^st 6 mos)
   • Repaired CHD with residual defects

Question 4

Dental Guidelines

Recommended for all dental procedures where gingival tissue or periapical region is manipulated, or perforation of the oral cavity

–Not needed for anesthesia, radiographs

Chlorhexidine: controversial in prevention of IE

Pt already on Abx: prescribe another Abx class or wait 10 days before usual regimen

Abx duration: 2g amoxicillin produce acceptable MIC for 6 hours (admin additional 2g if over 6h. OK to admin up to 2h after dental appt if didn’t prophy)

Other considerations: pt with prosthetic valves are on long-term anticoagulation (bleeding risk)

Nonvalvular cardiovascular devices: Rec’ Abx if I&D abscess, residual valve leak

IV catheters: no need prophylaxis

Answer 4