Bacterial Endocarditis


• Infection of endothelium of heart (including but not limited to the valves)

• Acute (ABE): infection of normal valves with a virulent organism (eg, S. aureus)

• Subacute (SBE): indolent infection of abnormal valves with a less virulent organism (eg,

S. viridans)

Predisposing conditions

• Abnormal valve high-risk: prior endocarditis, rheumatic valvular disease. AoV disease, complex cyanotic lesions, prosthesis (1.5-3% at 12 mos. 3-6% at 5 y) medium-risk: MV disease (including MVP w/ MR or leaflet thickening). HCMP

• Abnormal risk of bacteremia: IVDA. indwelling venous catheters (20% of bacteremic Pts develop endocarditis), poor dentition, hemodialysis, diabetes mellitus

Modified Duke Criteria



• Sustained bacteremia by an organism known to cause endocarditis (or 1 BCx or © serology for Coxietla)

• Endocardial involvement document by either

• echocardiogram (vegetation, abscess, prosthetic dehiscence) or new valvular regurgitation

• Predisposing condition (see above)

• Vascular phenomena: septic arterial or pulmonary emboli, mycotic aneurysms. ICH, Janeway lesions

• Immune phenomena: <S RF. GN. Osier's nodes. Roth spots

• © blood cx not meeting major criteria

Definitive (ie. highly probable): 2 major or 1 major * 3 minor or 5 minor criteria Possible: 1 major t- 1 minor or 3 minor criteria

(CID 2000.30:633)

(CID 2000.30:633)

Microbiology of Endocarditis

Native valve endocarditis (NVE)

Prosthetic valve endocarditis (PVE)

Microbiology of Endocarditis

Native valve endocarditis (NVE)

Prosthetic valve endocarditis (PVE)



(>6 mo post)

S. vindans et al.










S. aureus





S. epidermidis















Culture Q





Culture © = nutritionally-deficient streptococci. HACEK (Hoemophdut parainfluenza* & aphrophiíus. Actinoboortuj. Cardioöoctenum, Eifcenelfo, and Kmgetia), Bartonella, CoxieUa. Chlamydia, Legionella. Bruce/to

Culture © = nutritionally-deficient streptococci. HACEK (Hoemophdut parainfluenza* & aphrophiíus. Actinoboortuj. Cardioöoctenum, Eifcenelfo, and Kmgetia), Bartonella, CoxieUa. Chlamydia, Legionella. Bruce/to

(Adapted from Braunwald. E, ed.. Heart Dnease. 5th ed.. 1997; W. B. Saunders. Phila.) Clinical manifestations inejm 2001:3451318)

• Persistent bacteremia: fever (80-90%). anorexia, weight loss, night sweats, fatigue

• Valvular or perivalvular infection: new murmur. CHF. conduction abnormalities

• Septic emboli: systemic emboli (eg. to periphery. CNS. kidneys, spleen, or joints), pulmonary emboli (if right-sided), mycotic aneurysm. Ml (coronary artery embolism)

• Immune complex phenomena: arthritis, glomerulonephritis. © RF. T ESR

Physical exam

• HEENT: Roth spots (retinal hemorrhage • pale center), petechiae (conjunctivae, palate)

• Cardiac valvular regurgitation • thrill (fenestrated valve or ruptured chordae), muffled prosthetic valve sounds, pericardial rub. Frequent examinations for changing murmurs.

• Abdomen: tender splenomegaly

• Musculoskeletal: arthritis, vertebral tenderness

• Extremities (typically seen in SBE not ABE)

Janeway lesions (septic emboli nontender. hemorrhagic macules on palms or soles) Osier's nodes (immune complexes -» tender nodules on pads of digits) proximal nailbed splinter hemorrhages: clubbing

Diagnostic studies

• Blood cultures (before antibiotics): at least 3 sets (aerobic & anaerobic bottles) from different sites, ideally spaced -1 h apart / BCx (at least 2 sets) after appropriate antibiotics have been initiated to document clearance; repeat q24-48h until 0.

• CBC with differential. ESR. rheumatoid factor. BUN. Cr. U/A & UCx

• ECG (on admission and at regular intervals): to assess for new conduction abnormalities

• Echocardiogram: obtain TTE;TEE if (1) intermediate pretest probability (4-60%). (2)

prosthetic valve. (3) TTE nondiagnostic. (4) TTE © but endocarditis strongly suspected, or (5) suspect progressive or invasive infection (eg. persistent bacteremia or fever, new conduction abnormality, intracardiac shunt, etc.) (N^m 2001345:1318)






Transthoracic (TTE)




Transesophageal (TEE)




(Cftetf 1991:100351; ni}m 1991324:795: jacc 1991:18391;^ 1993:71:201)

(Cftetf 1991:100351; ni}m 1991324:795: jacc 1991:18391;^ 1993:71:201)


• Obtain culture data first

ABE — antibiotics should be started promptly after culture data obtained SBE —• if Pc hemodynamically stable, antibiotics may be delayed in order to properly obtain adequate blood culture data, especially in the case of prior antibiotic treatment

• Suggested empiric therapy native valve ABE: [naf + gent] or [vanco + gent] if high prev. of MRSA native valve SBE: penicillin/ampicillin + gentamicin prosthetic valve: vancomycin + gentamicin + rifampin

• Adjust antibiotic regimen based on organism and sensitivities

• Repeat BCx qd until Pt defervesces and BCx G-, usually 2-3 d

• Fever may persist up to 1 wk after appropriate antibiotic therapy instituted or in setting of metastatic sites of infection

• Systemic anticoagulation relatively contraindkated given risk of hemorrhagic transformation of cerebral embolic strokes (however, in absence of cerebral emboli, can continue anticoagulation for preexisting indication)

• Duration of therapy is usually 4-6 wks, except in cases of uncomplicated right-sided endocarditis, in which 2 wks of therapy may have comparable outcomes

Indications for surgery

• In general, try to deliver as many days of abx as possible, in hopes of 1 incidence of recurrent infection in prosthesis, as well as to improve structural integrity of tissue that will receive prosthesis

• Cerebral septic embolism historically considered a relative contraindication to immediate surgery as risk of hemorrhagic conversion during cardiopulmonary bypass high during the first 10-14 d; recent studies suggest in modern bypass area, risk lower (Stroke 2006:37:2094)

• Indications for surgery refractory CHF (ie. despite maximal. ICU-level medical therapy)

persistent or refractory infection (eg, ® BCx after 1 wk of appropriate IV abx and no drainable metastatic focus) invasive infection (ring abscess, worsening conduction; seen in 15% native. 60% prosthetic)

prosthetic valve, especially with valve malfunction or dehiscence or S. oureus infection hard-to-eradicate infections (eg. fungi) high risk for embolic complications


Endocarditis Prophylaxis

Cardiac conditions

Prosthetic valve; previous endocarditis; congenital heart disease (CHD) including unrepaired or incompletely repaired cyanotic CHD (palliative shunts or conduits). 1M 6 mos after completely repaired CHD using prosthetic material: cardiac transplant recipients w/ valvulopathy (Nb. prophylaxis no longer rec. in Pts w/ acquired valvular dysfxn. bicuspid AoV. MVP with leaflet thickening or regurgitation, HCMP)


Dental: that involve manipulation of gingival tissue or periapical region of teeth or perforation of oral mucosa (eg, extractions, periodontal procedures, implants, root canal, cleanings) Respiratory: incision or biopsy of respiratory mucosa (Nb. prophylaxis no longer rec. for Gl or GU procedures)


Oral: amoxicillin 2 g 30-60 min before

Unable to take PO: amp 2 g IM/IV or cefazolin or Cftx 1 g IM/IV PCN-allergic: clindamycin 600 mg PO/IM/IV

(Ore 2007:1 ISicpub)

(Ore 2007:1 ISicpub)

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