Bacterial Endocarditis

Aka: Bacterial Endocarditis, Infective Endocarditis, Infectious Endocarditis, Subacute Bacterial Endocarditis, Acute Endocarditis, Osler Node, Osler's Node, Janeway Lesion, Roth Spot, Roth's Spot, Prosthetic Valve Endocarditis

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II. Epidemiology

  1. Incidence: 5-8 cases per 100,000 persons in U.S.
  2. Native valve affected in over 70-80% of cases
  3. Acute mortality in hospitalized patients is as high as 15-20% (and 5 year mortality approaches 40%)
  4. Hospital acquired cases (nosocomial infections) are increasing in Incidence
  5. Age
    1. Median age of onset: 58 years old
    2. Males older than 50 years are more commonly affected
    3. Increasing Incidence in those over age 65 years old
      1. Related to degenerative Heart Valve Disease and implanted devices
    4. Uncommon in children outside of specific risk factors (esp. Congenital Heart Disease, indwelling venous catheters)

III. Types: Infective Endocarditis

  1. Native Valve Infective Endocarditis
    1. Community Acquired
    2. Health-Care Associated (Nosocomial Infectious Endocarditis)
    3. IV Drug Abuse
  2. Prosthetic Valve Endocarditis
    1. Early infection (<2 months after Heart Valve Replacement)
      1. Intraoperative prosthetic contamination
      2. Postoperative Infection
    2. Mid-Term Infection (2-12 months after Heart Valve Replacement)
    3. Late infection (>12 months after Valve Replacement)
      1. Same bloodborne pathogen entry as with native valves
      2. Risk of perivalvular invasion (e.g. myocardial abscess, Pericarditis)

IV. Types: Noninfective Endocarditis

  1. Endocarditis is assumed to be infectious initially
    1. These non-Bacterial valvular lesions form part of the differential diagnosis of valvular vegetations
  2. Nonbacterial Thrombotic Endocarditis (NBTE)
    1. Small, sterile, non-inflammatory vegetations form on the surface of previously normal valves
    2. Associated with Hypercoagulable state (e.g. pregnancy) and with catheter-related valvular injury
  3. Libman-Sacks Lesions
    1. Associated with Systemic Lupus Erythematosus and Antiphospholipid Antibody Syndrome
    2. May also be seen with HIV Infection, COVID-19, Granulomatosis with Polyangiitis
    3. Platelet and Fibrin vegetations form along valve leaflet closure
  4. Merantic Endocarditis
    1. Large thrombotic, non-Bacterial vegetations may form on abnormal valves with significant risk of embolic complications
    2. Associated with Disseminated Intravascular Coagulation, mucinous adenocarcinoma, chronic wasting or chronic infection
  5. References
    1. Ibrahim (2023) Libman Sacks Endocarditis, StatPearls, Treasure Island, FL, accessed 4/24/2023
    2. Hurrell (2020) Heart 106(13):1023-29 +PMID: 32376608 [PubMed]

V. Pathophysiology

  1. Two factor combination predisposes to the development of endocarditis
    1. Cardiac lesion: Intracardiac surface upon which the pathogens can adhere
      1. Prosthetic Heart Valve
      2. Native valve with congenital or acquired defect
    2. Bloodborne pathogen
      1. Bacteria
      2. Fungi
  2. Native Heart Valve Injury and Infection (80% of Infectious Endocarditis cases)
    1. Mitral valve and aortic valve are most likely to be involved
    2. Starts with endothelial damage
      1. Turbulent flow (e.g. valvular stenosis or valvular regurgitation)
      2. Intravascular device-related injury (e.g. catheters)
      3. Chronic inflammation (e.g. IVDA contaminated by particular matter)
    3. Injured endotholelium colonized with transient bacteremia (e.g. dental procedures, GI/GU surgery)
  3. Prosthetic Valve Infection (20% of Infectious Endocarditis cases)
    1. Infection types depend on timing from Prosthetic Valve Endocarditis (see above)
    2. Infection occurs at prosthetic valve sewing cuff or localized thrombus
      1. Unlike native valves, the prosthetic valve is inherently susceptible to infection

VI. Risk Factors

  1. Degenerative valvular disease (80% of native valve endocarditis cases)
    1. Primarily affect left sided Heart Valves (contrast with right sided involvement in IVDA)
    2. Mitral Regurgitation (43.4%)
    3. Aortic Regurgitation (26.3%)
    4. Calcific valvular heart disease
    5. Rheumatic Heart Disease (3.3%)
      1. Much higher Incidence in developing countries where Rheumatic Heart DiseaseIncidence still 10-15 per 1000
    6. Valve Replacement
      1. Risk 4% within first year of replacement, and 1% cumulative Incidence thereafter
  2. IV Drug Abuse (~10% of native valve endocarditis cases)
    1. Less than 50% of endocarditis in IV Drug Abuse is associated with a pre-existing structural cardiac defect
    2. IVDA and fever is associated with endocarditis in up to 15% (and bacteremia in up to 25-40%)
    3. Higher risk with Immunosuppression (e.g. HIV Infection)
    4. Staphylococcus aureus infection is most common
    5. Tricuspid valve endocarditis is nearly pathognomonic for IV Drug Abuse
      1. Tricuspid valve is rarely involved in other causes of Bacterial Endocarditis
      2. Larger bloodborne particulate matter in IVDA typically deposits on the tricuspid valve
      3. Smaller particulate matter (<10 um) may pass through lung capillaries and deposit on aortic valve or mitral valve
    6. Atypical presentation due to primarily right sided involvement
      1. No murmur typically heard
      2. Associated with septic pulmonary emboli
      3. Not associated with Splinter Hemorrhages or Conjunctival Hemorrhage
  3. Hospitalization or long-term care stay (Nosocomial Infectious Endocarditis)
    1. Defined as endocarditis onset within 3-60 days of a health care facility admission
    2. Accounts for 20% of Infectious Endocarditis
    3. Typically associated with invasive procedures or Intravenous Access
  4. Other Major Risk Factors
    1. Hemodialysis (7.9%)
    2. Chronic Intravenous Access
    3. Immunosuppression

VII. Causes: Predisposing lesion (60-80% of patients)

  1. Prosthetic Heart Valve
  2. Rheumatic Heart Disease (30%)
    1. Mitral valve more affected than Aortic valve
  3. Congenital Heart Disease (10-20%)
    1. Bicuspid aortic valve
    2. Pulmonary stenosis
    3. Ventricular Septal Defect
  4. Mitral Valve Prolapse (10-33%)
  5. Calcific Aortic Stenosis
  6. Asymmetric septal hypertrophy
  7. Marfan's Syndrome

VIII. Causes: Infection Sources

  1. IV Drug Abuse or IV Catheter related phlebitis
    1. Staphylococcus aureus
    2. Group A Streptococcus
    3. Gram Negative Rods
    4. Candida
  2. Dental procedures (including routine tooth cleaning)
    1. Viridans Streptococci
  3. Genitourinary procedures (includes Prostatic Massage)
    1. Enterococcus
    2. Gram Negative Rods
  4. Prosthetic Valve Recipient
    1. Staphylococcus epidermidis
    2. Staphylococcus aureus
    3. Diphtheroids
    4. Gram Negative Rods
    5. Candida
    6. Enterococcus
  5. Colonic neoplasm, villous adenoma or polyp
    1. Streptococcus bovis
  6. Homelessness or Alcoholism (and Body Lice)
    1. Bartonella Quintana
  7. Obstetric delivery
  8. Respiratory infection
  9. Skin Infection
  10. Cardiac surgery or cardiac catheterization

IX. Causes: Bacteria

  1. Staphylococcus aureus (31%, esp. IV Drug Abuse)
  2. Viridans Streptococcus (17%)
  3. Coagulase negative staphylococci (11%)
  4. Enterococci (11%)
  5. Streptococcus bovis (7%)
  6. Other causes (<2-5% each)
    1. Miscellaneous Streptococcus
    2. Fungi
    3. Gram negative HACEK Bacilli (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, and Kingella)
    4. Gram Negative non-HACEK Bacilli
    5. Bartonella (responsible for high number of culture negative endocarditis cases)
    6. Brucella
    7. Coxiella

X. History

  1. Recent hospitalizations
  2. Recent infections
  3. Indwelling catheters or devices
  4. Recent dental procedures
  5. Known murmur
  6. Structural heart disease (e.g. valvular stenosis, valvular regurgitation)
  7. Prosthetic Heart Valve
  8. Prior Infective Endocarditis
  9. Intravenous Drug Abuse
  10. Hemodialysis
  11. Immunosuppression (e.g. Diabetes Mellitus, HIV Infection)

XI. Symptoms: Typical Presentation

  1. Most endocarditis patients do not appear ill or septic
  2. Prodrome type symptoms
    1. Fever (>80-90% of cases)
      1. May be absent in elderly or immunosuppressed
    2. Chills
    3. Diaphoresis
    4. Myalgias (especially large Muscle groups)
    5. Fatigue
    6. Weight loss
    7. Anorexia
    8. Arthralgia
    9. Malaise
    10. Pallor
  3. Non-productive cough
    1. Present in up to 24% of cases
    2. Better when supine, worse when upright
  4. Cardiopulmonary symptoms (variably present)
    1. Chest Pain
    2. Shortness of Breath
  5. Classic endocarditis signs as below
    1. May only be present in severe Acute Endocarditis

XII. Signs: Classic Presentation (Osler)

  1. Precautions
    1. These classic findings are seen in late immunologic vascular complications
    2. Ideally, Infectious Endocarditis is diagnosed earlier, before these historically classic findings occur
    3. Careful evaluation may identify multiple foci of infection
      1. Skin findings (see below)
      2. Pneumonia
      3. Perinephric Abscess
      4. Cerebral emboli (focal Cerebrovascular Accident findings - see above)
  2. Cardiovascular Findings
    1. Congestive Heart Failure
      1. Present in severe cases
    2. Systolic Murmur from Heart Valve
      1. New murmur auscultated in 48% of careful examinations
      2. Most often a valve regurgitation murmur
      3. Characteristics change on serial exams
      4. Absent in tricuspid valve involvement (rare outside of IV Drug Abuse)
    3. Splenomegaly
  3. Skin Findings (uncommon, ~5% of cases)
    1. Petechiae on mucus membranes (mouth, Conjunctiva)
      1. Non-specific, but most common skin finding on presentation
    2. Splinter Hemorrhages
      1. Non-blanching linear lesions beneath nails
    3. Osler Nodes
      1. Painful, raised, violaceous Nodules affecting pulp of fingers and toes
    4. Janeway Lesions
      1. Blanching, erythematous, painless hemorrhagic Nodules on palms or soles
    5. Roth Spots
      1. Small Retinal Hemorrhages with central pallor
      2. Exudative, edematous Retinal lesions
    6. Digital Clubbing
  4. Neurologic Findings in 33% of cases (perform careful Neurologic Exam)
    1. Cerebrovascular Accident with focal neurologic changes
    2. Encephalopathy
    3. Meningitis
    4. Seizures

XIII. Presentations: Other

  1. Fever with Cerebrovascular Accident
    1. Consider endocarditis related embolic stroke
    2. Stroke is the initial presentation of endocarditis in 23% of cases
    3. Emboli to the brain account for 65% of endocarditis related embolic events
  2. Fever with Back Pain
    1. Consider septic emboli resulting in Vertebral Osteomyelitis or Spinal Epidural Abscess
  3. Fever with Acute Congestive Heart Failure
    1. Acute Aortic Regurgitation (Aortic Insufficiency) may result from endocarditis, leading to acute CHF
  4. Fever with a new Atrioventricular Block
    1. Perivalvular abscess is associated with new AV Block

XIV. Precautions

  1. Endocarditis Diagnosis is often missed initially due to non-specific symptoms and signs
    1. Typically presents as a viral-like syndrome
    2. Patients often appear non-toxic initially
    3. Fever may not be present at visit (but reported at home)
    4. Murmurs are often absent or only intermittently present
    5. Consider Blood Cultures and close interval follow-up in undifferentiated fever with myalgias
  2. Red Flags for which Endocarditis should be considered
    1. Endocarditis risk factors
      1. Prosthetic or malformed Heart Valve
      2. Intravenous Drug Abuse (IVDA)
      3. Hemodialysis
    2. Unexplained symptoms
      1. Fever
      2. Night Sweats
      3. Systemic illness

XV. Labs

  1. Blood Culture
    1. Obtain before starting empiric therapy
    2. Cultures should be obtained with careful antiseptic technique (not off IV lines)
    3. Obtain at least 3-5 ml for small children, 10 ml if older per culture (20 ml is preferred)
    4. Blood Culture timing need not coincide with fever (bacteremia is continuous)
    5. Obtain three cultures over at least one hour
      1. Three cultures are recommended as sufficient
      2. Test Sensitivity has been shown in the past to increase with additional cultures
        1. Four cultures: >90% sensitive
        2. Six cultures: 100% sensitive
    6. Repeat Blood Cultures (2 sets) are performed as part of the Antibiotic protocol below
      1. Repeated if suspected endocarditis if initial 3 Blood Cultures negative at 24-48 hours
      2. If positive and on Antibiotics, repeat every 24-48 hours until Blood Cultures are negative
    7. False Negative Rate: 10%
      1. Antibiotics prior to obtaining cultures
      2. Consider Serologic Testing for fastidious Bacteria (Bartonella, Coxiella, and Chlamydia)
  2. Urinalysis
    1. Proteinuria
    2. Microscopic Hematuria
  3. Complete Blood Count
    1. Leukocytosis (only present in 50% of cases)
    2. Normochromic, Normocytic Anemia (50% of cases)
  4. Acute phase reactants and other lab markers
    1. C-RP and ESR are recommended in suspected endocarditis, but they may add little to diagnosis
      1. Low Test Specificity
      2. Low Test Sensitivity (increased in 66% of cases)
    2. C-Reactive Protein (C-RP) elevated
    3. Sedimentation Rate (ESR) elevated
    4. Complement
      1. CH50 or C3 decreased
    5. Rheumatoid Factor positive
      1. Circulating immune complex
    6. Procalcitonin
      1. Not recommended routinely in endocarditis evaluation
      2. Yu (2013) Am J Emerg Med 31(6):935-41 [PubMed]
  5. Miscellaneous labs
    1. Comprehensive metabolic panel (all cases)
    2. Consider Coxiella and ChlamydiaSerology
    3. BartonellaSerology (Antibody titers >1:800) or tissue biopsy PCR
      1. Consider in culture negative cases, esp Alcoholism or Homelessness (or cat exposure)
  6. Markers of cardiac injury (consider as part of differential diagnosis depending on presentation)
    1. Serum Troponin
    2. Brain Natriuretic Peptide (BNP)

XVI. Diagnostics: Electrocardiogram (EKG)

  1. Evaluate for endocarditis complications as well as differential diagnosis
  2. Conduction abnormality in 26% of cases
  3. New AV nodal block (13% of cases)
    1. Periannular extension (valvular annulus, septum, Myocardium)
    2. Conduction abnormalities are seen in up to 26% of patients
    3. Associated with invasive infection and worse prognosis
    4. See complications below
    5. Meine(2001) Am Heart J 142(2):280-5 +PMID:11479467 [PubMed]
  4. Myocardial Ischemia or infarction
    1. Coronary emboli

XVII. Diagnosis

  1. See Duke Criteria for Infectious Endocarditis Diagnosis

XVIII. Imaging: Echocardiogram

  1. Transthoracic Echocardiogram
    1. Cornerstone of Duke Criteria for Infectious Endocarditis Diagnosis
    2. Recommended in all patients with suspected endocarditis
    3. Consider repeating Echocardiogram in 7-10 days in early cases, with high suspicion
    4. Findings
      1. Cannot differentiate active from healed lesion
      2. Vegetation in native valve endocarditis
        1. Test Sensitivity: 80% (range 50-90%), and very high in children
        2. Test Specificity: 90%
        3. Efficacy is much lower in Prosthetic Valve Endocarditis
      3. Other findings
        1. Systolic function
        2. Valvular function
        3. Endocarditis Complications
  2. Transesophageal Echocardiogram
    1. Efficacy
      1. Test Sensitivity for native valve Infective Endocarditis: 90-100%
      2. Efficacy is slightly lower for prosthetic valves
    2. Indications
      1. Staphylococcus bacteremia
      2. Thoracic views non-diagnostic or limited by Obesity
      3. Prosthetic valve (shadowing interferes with adequate valve viewing)
      4. Endocarditis prior history
      5. Structural valve abnormality

XIX. Imaging: Additional

  1. Chest XRay (all suspected Infectious Endocarditis cases)
    1. Evaluate differential diagnosis
    2. Lung Abscess
    3. Pulmonary Infarction
    4. Congestive Heart Failure
  2. Advanced imaging
    1. Imaging as needed for embolic events (e.g. MRI Brain)
    2. Cardiac Imaging (e.g. Cardiac MRI, ekg-gated Cardiac CT)
    3. PET/CT (18F-FDG) or SPECT/CT (Leukocyte labeled)
      1. Consider in suspected Prosthetic Valve Endocarditis

XX. Differential Diagnosis

  1. Viral syndrome
  2. Acute Rheumatic Fever
  3. Atrial Myxoma
  4. Libman-Sacks Endocarditis
    1. Non-Bacterial Endocarditis associated with Systemic Lupus Erythematosus, Antiphospholipid Antibody Syndrome
  5. Marantic Endocarditis
    1. Nonbacterial thrombotic endocarditis (NBTE) associated with adenocarcinoma
  6. Primary neurologic disorder
  7. Occult neoplasm
  8. Myocarditis
  9. Fever of Unknown Origin (bacteremia from other occult causes)
  10. IV Drug Abuse
  11. Central catheter Sepsis
  12. Spinal Epidural Abscess

XXI. Management: General Measures

  1. Early multi-specialty Consultation (cardiology, cardiothoracic surgery, infectious disease)
  2. See ABC Management
  3. See Acute Pulmonary Edema Management
  4. See Septic Shock
  5. Remove implantable cardioverter Defibrillators and Pacemakers with evidence of device infection
  6. Other longterm measures
    1. Remove IV catheters as soon as Antibiotics are completed
    2. Repeat Echocardiogram at the end of Antibiotic therapy
      1. Documents new baseline echo

XXII. Management: Antibiotics

  1. Obtain Blood Cultures before starting empiric therapy (see above)
  2. In non-critically ill patients, delay treatment until Blood Culture and Echocardiogram confirm diagnosis
    1. If Septic Shock or other hemodynamic instability, Antibiotics must be started after cultures obtained
    2. Do not delay treatment beyond Blood Cultures in children (rapid decompensation may occur)
  3. Antibiotic Course
    1. Antibiotics IV for at least 4 weeks (native valves) to at least 6 weeks (prosthetic valves)
    2. Specific to organisms cultured
    3. Duration of therapy is based from the first day in which Blood Cultures are negative
      1. Obtain two sets of Blood Cultures every 24-48 until Blood Cultures are negative
    4. Antibiotics are initiated inpatient and then when clinically stable, at home via home care
      1. Re-evaluation in clinic following discharge should be within 7-14 days
      2. Obtain Complete Blood Count, Serum Creatinine and Antibiotic levels at follow-up
  4. Antibiotics: Initial Empiric Treatment
    1. Protocol 1 - Native Valve
      1. Vancomycin 15-20 mg/kg every 8-12 hours IV (max 2 g, target trough 15-20 mcg/ml) AND
      2. Ceftriaxone 2 grams every 24 hours IV
    2. Protocol 2 - Native Valve
      1. Vancomycin 15-20 mg/kg every 8-12 hours IV (max 2 g, target trough 15-20 mcg/ml) AND
      2. Gentamicin 1 mg/kg every 8 hours IV or IM
    3. Protocol 3 - Prosthetic Valve
      1. Vancomycin 15-20 mg/kg every 8-12 hours IV (max 2 g, target trough 15-20 mcg/ml) AND
      2. Gentamicin 1 mg/kg every 8 hours IV or IM AND
      3. Rifampin 300 mg PO/IV every every 8 to 12 hours
    4. Alternative agents
      1. Vancomycin alternative in native valve empiric therapy
        1. Daptomycin 6 mg/kg IV every 24 hours (every 48 hours if Creatinine Clearance <30 ml/min)
  5. Antibiotics: Viridans Streptococcus or Streptococcus bovis
    1. Penicillin Susceptible
      1. Penicillin G or Ceftriaxone for 4 weeks or
      2. Gentamicin AND (Penicillin G or Ceftriaxone) for 2 weeks or
      3. Vancomycin 15-20 mg/kg every 8-12 hours IV (target trough 15-20 mcg/ml) for 4 weeks
        1. Beta-lactams are preferred over Vancomycin, unless Antibiotic Resistance, allergy
    2. Penicillin Intermediate Sensitivity
      1. Gentamicin for 2 weeks AND (Penicillin G or Ceftriaxone) for 4 weeks or
      2. Vancomycin 15-20 mg/kg every 8-12 hours IV (target trough 15-20 mcg/ml) for 4 weeks
    3. Penicillin Resistant
      1. Gentamicin AND (Penicillin G or Ampicillin) for 4 to 6 weeks or
      2. Vancomycin 15-20 mg/kg every 8-12 hours IV (target trough 15-20 mcg/ml) for 6 weeks
  6. Antibiotics: Coagulase negative Staphylococcus
    1. Background
      1. Second most common endocarditis cause following Valve Replacement (and frequent Blood Culture contaminant)
      2. Staphylococcus lugdunensis is a virulent coagulase negative Staphylococcus that may also infect native valves
    2. Oxacillin-Susceptible (Coagulase negative Staphylococcus)
      1. Nafcillin or Oxacillin for 6 weeks AND
      2. Rifampin 300 mg IV/PO for 6 weeks AND
      3. Gentamicin 1 mg/kg every 8 hours IV or IM for 2 weeks
    3. Oxacillin-Resistant (Resistant coagulase negative Staphylococcus)
      1. Vancomycin 15-20 mg/kg every 8-12 hours IV (target trough 15-20 mcg/ml) for 6 weeks AND
      2. Rifampin 300 mg IV/PO for 6 weeks AND
      3. Gentamicin 1 mg/kg every 8 hours IV or IM for 2 weeks
  7. Antibiotics: Staphylococcus aureus
    1. MSSA
      1. Nafcillin or Oxacillin for 6 weeks AND
      2. Rifampin 300 mg IV/PO (if prosthetic valve) for 6 weeks AND
      3. Gentamicin 1 mg/kg every 8 hours IV or IM (if prosthetic valve) for 2 weeks
    2. MRSA
      1. Vancomycin 15-20 mg/kg every 8-12 hours IV (target trough 15-20 mcg/ml) for 6 weeks AND
      2. Rifampin 300 mg IV/PO (if prosthetic valve) for 6 weeks AND
      3. Gentamicin 1 mg/kg every 8 hours IV or IM (if prosthetic valve) for 2 weeks
  8. Antibiotics: Enterococcus
    1. Penicillin, Ceftriaxone, Gentamicin, Vancomycin sensitive
      1. Ceftriaxone and Ampicillin for 6 weeks or
      2. Gentamicin and (Ampicillin or Penicillin G) for 4 to 6 weeks (4 weeks for native valve) or
      3. Gentamicin and Vancomycin for 6 weeks
    2. Penicillin, and Vancomycin (and Streptomycin) sensitive, but resistant to Gentamicin
      1. Streptomycin and (Ampicillin or Penicillin G) for 4 to 6 weeks or
      2. Streptomycin and Vancomycin for 6 weeks
    3. Gentamicin and Vancomycin sensitive, but resistant to Penicillin
      1. Gentamicin and Ampicillin-Sulbactam (Unasyn) for 6 weeks or more or
      2. Gentamicin and Vancomycin for 6 weeks
  9. Antibiotics: Gram Negatives
    1. Ceftriaxone for 4-6 weeks (6 weeks for prosthetic valves)
  10. Antibiotics: Bartonella
    1. Ceftriaxone 2 g IV every 24 hours for 6 weeks (or until Bartonella confirmed as causative) AND
    2. Gentamicin 1 mg/kg IV every 8 hours for first 2 weeks (or Rifampin 300 mg IV or oral) AND
    3. Doxycycline 100 mg oral or IV twice daily for 6 weeks (or Azithromycin 250 mg daily)
  11. Experimental
    1. Oral Antibiotics for endocarditis may be effective after using 2 weeks of IV Antibiotic therapy as above
      1. Stable patients with negative Blood Cultures
    2. May be indicated in left sided endocarditis native or prosthetic valve (mitral valve or aortic valve)
      1. Could be considered in non-compliant patients who refuse to continue IV medications
      2. Alternatively once weekly ParenteralAntibiotics may be considered (e.g. Dalbavancin, Oritavancin)
    3. Oral Protocols
      1. Streptococcus or Enterococcus
        1. Amoxicillin 1000 mg four times daily (high dose)
      2. Staphylococcus (MSSA)
        1. Dicloxacillin 1000 mg four times daily (high dose) AND Rifampin
      3. MRSA
        1. Linezolid
    4. References
      1. (2018) Presc Lett 25(11):62
      2. (2023) Presc Lett 30(1)
      3. Iversen (2018) N Engl J Med +PMID:30152252 [PubMed]
  12. References
    1. Gilbert (2016) Sanford Guide to Antibiotics, IOS app accessed 4/13/2016
    2. Bonow (2006) J Am Coll Cardiol 48(3): e1-e148 [PubMed]

XXIII. Management: Cardiovascular Surgery

  1. Indications (required in 50% of cases)
    1. Moderate to Severe Acute Heart Failure (Pulmonary Edema, Cardiogenic Shock)
      1. Most common indication (esp. for surgically treatable process, regardless of IE confirmation)
    2. Fungal endocarditis or other difficult to treat organisms
    3. Prosthetic Valve Endocarditis (higher risk of Heart Failure and invasive infection)
      1. Highest risk in first 3 months after surgery (as well as for the first year after surgery)
      2. May be compounded by other prosthetic valve complications (e.g. thrombosis, regurgitation, Hemolysis)
    4. Persistently positive Blood Culture despite therapy beyond the first week
    5. Recurrent emboli in the first 2 weeks of treatment
    6. Severe valvular regurgitation (Aortic Regurgitation, Mitral Regurgitation)
      1. Best outcomes with early surgery (regardless of Infective Endocarditis)
    7. Large vegetation
    8. Paravalvular extension of infection (persistent fevers or positive cultures despite Antibiotics, identified on TEE)
      1. Valve ring or myocardial abscess
      2. Valve dehiscence or fistula
      3. Heart Block or other EKG conduction defects
  2. Efficacy
    1. Based on retrospective study
    2. Early surgery improves survival over Antibiotic alone
      1. Surgery within first 2 days of admission
      2. Survival
        1. Surgery patient survival: 79% in hospital (60% at 8 year follow-up)
        2. Medical therapy (Antibiotics without surgery) survival: 55% in hospital (35% at 8 years)
    3. References
      1. Bishara (2001) Clin Infect Dis 33:1636-43 [PubMed]
      2. Murdoch (2009) Ann Intern Med 169(5): 463-73 [PubMed]

XXIV. Complications

  1. Cardiovascular complications (30-50% of cases)
    1. Precautions
      1. Cardiovascular complications are the most common cause for surgery and for death
    2. Heart Failure (right or left) typically due to Valvular Regurgitation
      1. See Cardiogenic Shock
      2. Associated with poor prognosis
      3. Valve perforation
      4. Mitral chordae rupture
      5. Valve obstruction (large vegetation)
    3. Perivalvular abscess (up to 30-40% of cases)
      1. Associated with worse prognosis (systemic embolization risk)
      2. Associated with conduction abnormalities (esp. when aortic valve involved)
      3. Consider when EKG abnormalities or persistent fever or bacteremia despite Antibiotics
    4. Periannular or Perivalvular extension of infection (myocardial abscess, valve ring, Valve dehiscence, septal fistula)
      1. May present as a new AV Nodal Block
      2. Increased mortality risk
      3. May require cardiac pacing
    5. Other cardiac complications
      1. Valvular destruction (valve cusps, leaflets or chordae tendinae)
      2. Pericarditis
      3. Aortic valve dissection
      4. Intracardiac fistula
  2. Renal complications
    1. Glomerulonephritis
    2. Renal Infarction
    3. Renal Abscess
  3. Musculoskeletal complications (esp. Staphylococcus aureus Infective Endocarditis)
    1. Vertebral Osteomyelitis
    2. Septic Arthritis
  4. Neurologic complications (33% of cases)
    1. Cerebrovascular Accident (CVA) or Transient Ischemic Attack (TIA)
      1. Typically affects the Middle Cerebral Artery distribution
    2. CNS emboli
      1. Stop Anticoagulation for 2 weeks in Staphylococcus aureus Prosthetic Valve Endocarditis with CNS emboli
    3. Mycotic aneurysm (rare)
    4. Meningitis
    5. Encephalitis or encephalopathy
    6. Cerebral mycotic aneurysm
    7. Cerebral Abscess
    8. Cerebral Hemorrhage
    9. Seizure Disorder
  5. Miscellaneous complications
    1. Septic Shock
    2. Splenic infarction
    3. Pulmonary Embolism and Lung Infarction

XXV. Prevention: Recurrent Endocarditis

  1. Obtain 3 Blood Culture sets at each subsequent febrile illness (prior to start of Antibiotics)
  2. Practice good Dental Hygiene with regular dental visits
  3. Endocarditis Prophylaxis
    1. See SBE Prophylaxis for indicated procedures

XXVI. Prognosis: Poor prognostic factors

  1. Advanced age
  2. Female gender
  3. Staphylococcus aureus Infective Endocarditis
  4. Healthcare-associated infection
  5. Heart Failure
  6. Prosthetic Valve Endocarditis
  7. Diabetes Mellitus
  8. Embolization complications
  9. Perivalvular Abscess
  10. Large vegetations
  11. Altered Mental Status
  12. Cardiac conduction abnormalities on EKG (see above)
  13. Other conditions associated with poor surgical candidacy

XXVII. References

  1. (2015) Presc Lett 22(12): 69
  2. Carr and Swaminathan in Herbert (2022) EM:Rap 22(2): 5-7
  3. Orman and Mattu in Herbert (2015) EM:Rap 15(1): 9-11
  4. Pacheco and Rawani-Patel (2019) Crit Dec Emerg Med 33(5): 3-11
  5. Pelletier (1991) in Harrison's Medicine, p. 972
  6. Vlasic (2015) Crit Dec Emerg Med 29(7): 12-9
  7. Vlasic (2021) Crit Dec Emerg Med 35(1): 17-24
  8. Baddour (2015) Circulation 132: 1435-86 +PMID: 26373316 [PubMed]
  9. Habib (2009) Eur Heart J 30(19): 2369-413 [PubMed]
  10. Hoen (2013) N Engl J Med 368(15):1425-33 +PMID:23574121 [PubMed]
  11. Murdoch (2009) Arch Intern Med 169(5): 463-73 [PubMed]
  12. Pierce (2012) Am Fam Physician 85(10): 981-6 [PubMed]

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