Infective Endocarditis Management (AHA/ESC 2023)

Algorithm Steps

1. ▶

   Start

   Suspected Infective Endocarditis

   Fever + new murmur, embolic phenomena, or risk factors (IVDU, prosthetic valve, prior IE)

   1. ●

      Action

      Initial Workup

      Blood cultures and imaging

      • 3 sets blood cultures from separate sites before antibiotics
      • CBC, BMP, ESR, CRP, urinalysis
      • ECG (assess for conduction abnormalities)
      • Chest X-ray
      1. ◆

         Decision

         TTE or TEE?

         Select appropriate echocardiography

         • TTE first if: Native valve, good image quality expected
         • TEE indicated if: Prosthetic valve, prior IE, poor TTE windows, high clinical suspicion with negative TTE
         • TEE sensitivity ~90-100% vs TTE ~40-60% for vegetations
         1. ●

            Action

            Apply Modified Duke Criteria

            Definite, Possible, or Rejected

            • Major: Typical organisms from 2 blood cultures, echo findings (vegetation, abscess, dehiscence), new valvular regurgitation
            • Minor: Predisposition, fever >38°C, vascular phenomena, immunologic phenomena, supportive microbiology
            • Definite: 2 major OR 1 major + 3 minor OR 5 minor
            1. ◆

               Decision

               Native or Prosthetic Valve?

               Determines empiric therapy and duration

               1. ●

                  Action

                  Native Valve Empiric Therapy

                  Before culture results

                  • Ampicillin-sulbactam 12g/day IV divided q4h
                  • PLUS Gentamicin 3mg/kg/day IV divided q8h
                  • If MRSA risk: ADD Vancomycin 30mg/kg/day divided q12h
                  • Alternative: Vancomycin + Gentamicin + Ciprofloxacin
                  1. ◆

                     Decision

                     Blood Culture Results

                     Tailor therapy to organism

                     1. ●

                        Action

                        Staphylococcus aureus

                        MSSA vs MRSA

                        • MSSA NVE: Nafcillin/Oxacillin 12g/day IV x6 weeks
                        • MRSA NVE: Vancomycin x6 weeks (consider adding rifampin)
                        • MSSA PVE: Nafcillin + Rifampin + Gentamicin x 6+ weeks
                        • MRSA PVE: Vancomycin + Rifampin + Gentamicin x 6+ weeks
                        1. ⚠

                           Warning

                           Surgical Indications

                           Early surgery consultation

                           • Heart failure from valve dysfunction
                           • Uncontrolled infection (abscess, enlarging vegetation, persistent bacteremia >7 days)
                           • Prevention of embolism: Large mobile vegetation >10mm (especially after embolic event)
                           • PVE with Staph or fungal infection
                           • Timing: Within 24-48h for severe HF, within 1-2 weeks for others
                           1. ●

                              Action

                              Monitoring & Follow-up

                              During and after treatment

                              • Daily assessment for complications
                              • Repeat blood cultures q48-72h until negative
                              • Weekly CBC, renal function, drug levels
                              • Repeat echo if clinical change or pre-surgery
                              • Post-treatment: Dental evaluation, surveillance cultures
                              1. ✓

                                 Outcome

                                 Successful Treatment

                                 Resolution of infection

                                 • Afebrile, negative cultures, no embolic events
                                 • Complete antibiotic course
                                 • Long-term follow-up for relapse
                              2. ⚠

                                 Warning

                                 Complications/Failure

                                 Poor outcome or relapse

                                 • Mortality: 15-30% (higher with S. aureus, PVE)
                                 • Relapse: Repeat cultures, consider resistance
                                 • Embolic stroke, heart failure, renal failure
                                 • Consider palliative care if not surgical candidate
                     2. ●

                        Action

                        Viridans Strep / S. bovis

                        PCN-susceptible streptococci

                        • PCN-susceptible (MIC ≤0.12): Penicillin G or Ceftriaxone x4 weeks
                        • OR 2-week course with Gentamicin
                        • Relatively resistant (MIC 0.25-2): Add Gentamicin x2 weeks
                        • PVE: 6 weeks duration minimum
                     3. ●

                        Action

                        Enterococcus

                        E. faecalis or E. faecium

                        • Ampicillin-susceptible: Ampicillin + (Ceftriaxone OR Gentamicin) x6 weeks
                        • Ampicillin-resistant: Vancomycin + Gentamicin x6 weeks
                        • VRE: Daptomycin 8-10mg/kg/day (consider linezolid)
                        • Gentamicin x4-6 weeks (monitor levels/renal function)
                     4. ●

                        Action

                        HACEK / Culture-Negative

                        Fastidious organisms

                        • HACEK: Ceftriaxone 2g IV daily x4 weeks (6 weeks PVE)
                        • Culture-negative: Ampicillin-sulbactam + Gentamicin
                        • Consider Q fever (Coxiella): Doxycycline + Hydroxychloroquine
                        • Bartonella: Doxycycline + Gentamicin
               2. ●

                  Action

                  Prosthetic Valve Empiric Therapy

                  Broader coverage required

                  • Vancomycin 30mg/kg/day IV divided q12h
                  • PLUS Gentamicin 3mg/kg/day IV divided q8h
                  • PLUS Rifampin 900mg/day PO divided q8h
                  • De-escalate when culture/susceptibility available