298.1 🎓 醫孞生版

298.1.0.1 📌 䞀頁重點

298.1.0.1.1 Epidemiology + Pathogenesis
298.1.0.1.1.1 Incidence
  • ~ 3-10 per 100,000 population/year
  • ↑ With age, IV drug use, prosthetic devices
  • Increasing healthcare-associated cases
298.1.0.1.1.2 Predisposing Conditions
  • Structural heart disease: degenerative valve disease, congenital, rheumatic, prosthetic valve
  • IV drug use: ↑ R-sided IE (tricuspid)
  • Indwelling catheters / lines
  • HD patients
  • Immunocompromised
  • Skin breakdown (ulcers, surgery)
298.1.0.1.1.3 Pathogenesis
  • Damaged endothelium + transient bacteremia → adhesion → biofilm → vegetation
  • Vegetation = thrombus + fibrin + platelets + organisms
  • Distal embolization: brain, kidney, spleen, liver, vascular system
  • Immune complex deposition: glomerulonephritis, vasculitis
298.1.0.1.1.4 Site of Involvement
  • Mitral > aortic > tricuspid > pulmonic
  • IV drug users: tricuspid > others
  • Prosthetic: aortic > mitral
298.1.0.1.2 Causative Organisms
298.1.0.1.2.1 Viridans Streptococci
  • Most common in subacute NVE
  • Source: oral cavity
  • Examples: S. sanguinis, S. mitis, S. mutans
  • Penicillin-sensitive most
298.1.0.1.2.2 Staphylococcus aureus
  • Most common IE worldwide overall (acute, aggressive)
  • Healthcare-associated, IV drug use, skin source
  • MRSA increasing
  • Higher mortality
  • Aggressive surgery often needed
298.1.0.1.2.3 Coagulase-Negative Staph (CoNS)
  • Prosthetic valve common
  • Indolent course
  • Skin/healthcare source
298.1.0.1.2.4 Enterococcus
  • E. faecalis most common
  • Elderly + GI/GU source
  • VRE in healthcare
  • Synergy with ampicillin + ceftriaxone (rather than aminoglycoside) in many cases (DAILY trial)
298.1.0.1.2.5 Strep gallolyticus (S. bovis)
  • Strong association with colorectal cancer — workup
  • Older, GI source
298.1.0.1.2.6 HACEK Organisms
  • Haemophilus, Aggregatibacter, Cardiobacterium, Eikenella, Kingella
  • Slow-growing Gram-negative
  • Indolent course
  • Ceftriaxone treatment
298.1.0.1.2.7 Culture-Negative IE
  • 5-10% of cases
  • Prior antibiotics
  • Fastidious organisms (HACEK, Bartonella, Brucella, Tropheryma, Coxiella burnetii — Q fever)
  • Fungi (Candida)
  • Non-infectious: Libman-Sacks, marantic (cancer)
298.1.0.1.2.8 Bartonella
  • Cat scratch (B. henselae)
  • Homeless / lice (B. quintana)
  • Culture-negative; serology + PCR
298.1.0.1.2.9 Coxiella (Q fever)
  • Ruminants exposure
  • Serology + PCR
298.1.0.1.2.10 Tropheryma whipplei
  • Rare
  • Whipple’s disease association
298.1.0.1.2.11 Fungal (Candida)
  • Immunocompromise, IV drug
  • Large vegetations, high embolic risk
  • Echinocandin + valve surgery
298.1.0.1.3 Clinical Presentation
298.1.0.1.3.1 Symptoms
  • Fever (~ 90%)
  • Constitutional: malaise, weight loss, sweats, anorexia
  • HF symptoms: dyspnea, edema (from valve destruction)
  • Embolic phenomena: stroke (15-30%), peripheral, mesenteric, splenic, renal
  • Petechiae: skin, conjunctiva, palate
298.1.0.1.3.2 Examination
  • Heart murmur new or changing (85%)
  • Splinter hemorrhages: under nail bed
  • Osler nodes: painful, palms/soles (immune complex)
  • Janeway lesions: painless, palms/soles (septic emboli)
  • Roth spots: retinal hemorrhages with pale center
  • Conjunctival petechiae
  • Splenomegaly
  • Signs of HF (S3, edema, JVD)
  • Septic embolic findings
298.1.0.1.4 Diagnosis — Modified Duke Criteria (2023 ESC Update)
298.1.0.1.4.1 Definite IE
  • 2 major OR
  • 1 major + 3 minor OR
  • 5 minor
298.1.0.1.4.2 Possible IE
  • 1 major + 1 minor OR
  • 3 minor
298.1.0.1.4.3 Rejected
  • Alternative diagnosis OR
  • Resolution within 4 days of antibiotics OR
  • No evidence at autopsy/surgery
298.1.0.1.4.4 Major Criteria

Blood Culture Evidence - Typical organism in 2 separate cultures (viridans Strep, Strep gallolyticus, HACEK, S. aureus, community-acquired Enterococcus without primary focus) - Persistent positive cultures (3 separate from > 1 hr apart with typical organism) - Single positive for Coxiella OR phase I IgG ≥ 1:800

Imaging Evidence (2023 Updates) - Echocardiogram: vegetation, abscess, pseudoaneurysm, new partial dehiscence of prosthesis - CT (cardiac): paravalvular extension, abscess (especially prosthetic) - FDG-PET / CT or SPECT (white cell scintigraphy): abnormal activity around prosthetic valve > 3 months post-implantation - New endocardial regurgitant flow / new partial dehiscence of prosthetic valve

298.1.0.1.4.5 Minor Criteria
  1. Predisposition: structural heart disease, IV drug use
  2. Fever ≥ 38°C
  3. Vascular phenomena: emboli, mycotic aneurysm, septic infarcts, Janeway lesions, conjunctival hemorrhage, intracranial hemorrhage
  4. Immunologic phenomena: Osler nodes, Roth spots, glomerulonephritis, RF+, CRP ↑
  5. Microbiologic evidence: positive blood culture but not meeting major criteria, OR serologic evidence of organism
298.1.0.1.5 Imaging
298.1.0.1.5.1 TTE
  • First-line
  • 60-70% sensitive for vegetation
  • 95%+ specific
298.1.0.1.5.2 TEE
  • More sensitive (90%+)
  • Indicated when:
    • Suspected IE with negative TTE
    • Prosthetic valve
    • Complications (abscess, fistula, leaflet perforation)
  • Better for left-sided + posterior structures
298.1.0.1.5.3 CT (Cardiac)
  • Paravalvular extension
  • Annular abscess
  • Pseudoaneurysm
  • Complements echo
298.1.0.1.5.4 FDG-PET / CT
  • For prosthetic valve > 3 months post-implant
  • CIED-related IE
  • Embolic sites identification
  • Used in 2023 ESC criteria
298.1.0.1.6 Treatment
298.1.0.1.6.1 Empiric IV Antibiotics (Before Culture Results)

Native Valve IE: - Vancomycin + ceftriaxone OR - Vancomycin + gentamicin (covers Strep + S. aureus + Enterococcus)

Prosthetic Valve IE (see Ch298): - Vancomycin + gentamicin + rifampin (within 12 months) OR similar

IV Drug User (R-sided IE): - MRSA coverage essential: vancomycin OR daptomycin

298.1.0.1.6.2 Targeted Antibiotics (After Culture)

Viridans Strep (pen-sensitive): - Penicillin G IV × 4 weeks OR - Ceftriaxone × 4 weeks - + Gentamicin × 2 weeks (synergy)

Viridans Strep (relatively resistant): - Penicillin G IV + gentamicin × 4 weeks

S. aureus (MSSA): - Nafcillin OR oxacillin × 4-6 weeks

S. aureus (MRSA): - Vancomycin OR daptomycin × 4-6 weeks - Daptomycin alternative for non-pulmonary IE (high doses)

Enterococcus: - Ampicillin + gentamicin × 4-6 weeks OR - Ampicillin + ceftriaxone × 6 weeks (less nephrotoxicity; DAILY trial) - Vancomycin if penicillin allergy

HACEK: - Ceftriaxone × 4 weeks

Coxiella (Q fever): - Doxycycline + hydroxychloroquine × 18-24 months minimum

Bartonella: - Doxycycline + gentamicin OR rifampin × 6 weeks

Fungal (Candida): - Echinocandin (caspofungin, micafungin) + valve surgery - Long-term suppression with fluconazole

298.1.0.1.6.3 Duration
  • Native valve: 4-6 weeks typically
  • Prosthetic: 6 weeks minimum
  • Severe / abscess: longer
298.1.0.1.6.4 Outpatient Parenteral Antibiotic Therapy (OPAT)
  • Stable patients
  • POET trial (2019) supports oral switch after IV stability
298.1.0.1.6.5 POET Trial (2019) — Partial Oral Treatment
  • N = 400 NVE
  • Stable after 10 d IV + clinical improvement
  • Switch to oral antibiotics (specific tailored)
  • Non-inferior outcomes
  • Practice-changing
298.1.0.1.7 Indications for Surgery
298.1.0.1.7.1 Class I Indications (Don’t Delay)

Heart Failure: - Severe AR/MR causing HF - Severe valve obstruction causing HF - Within hours-days

Uncontrolled Infection: - Persistent bacteremia ≥ 7 days despite appropriate IV antibiotics - Locally invasive (abscess, fistula, pseudoaneurysm, heart block) - Fungal IE - MDR organism

Embolic Risk: - Large vegetation > 10 mm + recurrent emboli despite appropriate treatment - Large vegetation > 10 mm + associated severe valve regurgitation - Vegetation > 15 mm and high embolic risk

298.1.0.1.7.2 Class IIa Indications
  • Recurrent embolism + large vegetation
  • Prosthetic IE (Ch298) — typically surgical
298.1.0.1.7.3 Timing
  • Emergent (within 24 hr): hemodynamic instability, refractory HF, severe acute regurgitation
  • Urgent (1-7 days): persistent infection, abscess, recurrent emboli
  • Elective: stable, after antibiotic completion
298.1.0.1.7.4 POSEDI / SET (Surgery in IE Trials)
  • Earlier surgery for severe IE complications shows mortality benefit
  • Specialized IE/endocarditis team approach
298.1.0.1.8 Complications
298.1.0.1.8.1 Cardiac
  • HF (50%): mortality predictor
  • Heart block (abscess invading conduction)
  • Pericarditis, intracardiac fistula
  • Acute regurgitation
298.1.0.1.8.2 Embolic
  • Stroke (15-30%)
  • Splenic abscess, infarct
  • Renal infarct
  • Mesenteric ischemia
  • Mycotic aneurysm (cerebral) — high mortality if rupture
298.1.0.1.8.3 Renal
  • Glomerulonephritis (immune complex)
  • Direct embolic infarct
  • Antibiotic toxicity (vancomycin, aminoglycosides)
298.1.0.1.8.4 Other
  • Septic shock
  • Embolic infarction of brain, lung, spleen, kidney
298.1.0.1.9 Prophylaxis (2024 ACC/AHA Update)
298.1.0.1.9.1 High-Risk Patients (Class I)
  • Prosthetic cardiac valve
  • Prior infective endocarditis
  • Unrepaired cyanotic CHD
  • Repaired CHD with prosthetic material < 6 months
  • Repaired CHD with residual defect at site of prosthetic material
  • Cardiac transplant with valvulopathy
298.1.0.1.9.2 Procedures (Class I)
  • Dental procedures with manipulation of gingival tissue or apical region of teeth or perforation of oral mucosa
298.1.0.1.9.3 Antibiotic Regimens
  • Amoxicillin 2 g PO 30-60 min pre-procedure (or cefazolin / ampicillin IV)
  • Allergic: cephalexin 2 g, clindamycin 600 mg, azithromycin 500 mg, doxycycline 100 mg

298.1.0.2 🩺 床邊速查

  • Most common IE worldwide: S. aureus (acute, aggressive)
  • Most common subacute NVE: viridans Strep (oral)
  • Strep gallolyticus IE: colon cancer workup!
  • Diagnosis: Modified Duke criteria (2023 ESC update)
  • Imaging: TTE → TEE → FDG-PET-CT (esp prosthetic)
  • Empiric: vancomycin + ceftriaxone OR vanc + gentamicin
  • Surgery indications: HF / persistent bacteremia / abscess / large veg + embolism / fungal
  • Prophylaxis: high-risk + dental gingival manipulation only