Infective Endocarditis

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Infective Endocarditis

• October 11, 2005
• Dr. Kanagala

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Microbiology Organisms Responsible

• Bacteria are the predominant cause
• Fungi
• Rickettsia
• Chlamydia
• Microorganisms vary dependent on risk factors
  predisposing patient to IE
• Staph Aureus single most common cause

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Native Valve Endocarditis

• Streptococcus responsible for more than 50 of
  cases
• Staphylococci
• Enterococci
• Infection occurs most frequently in those with
  preexisting valvular abnormality

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Staphylococci

• Causes endocarditis in those with normal and
  abnormal valves
• Most are coagulase positive S.Aureus
• Causes destruction of valves, multiple distal
  abscesses, myocardial abscesses, conduction
  defects, and pericarditis

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Enterococci

• Patients generally have underlying valvular
  disease
• May occur following manipulation of genitourinary
  or lower gastrointestinal tract
• Remainder of cases caused by Haemphilus
  Actinobacillus, Cardiobacterium, Eikenella,
  Kingella, Bartonella, or Coxiella Burnetti

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Diagnosis

• Negative culture can occur in 5 of patients.
• 1/3 to ½ are negative due to prior antibiotic use
• In patients with culture negative IE, advise lab
  to allow specialized testing to recover the
  causative organism which is needed to adequately
  treat

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IDU associated IE

• Skin flora and contaminated injection devices are
  the most frequent sources involved in
  IDU-associated IE
• S. Aureus Most common (50 of cases)
• Streptococcal species
• Gram negative Bacilli
• Pseudomonas
• Serratia species
• Fungi
• Candida

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Prosthetic Valve Endocarditis

• Most commonly occur during the perioperative
  period
• S. epidermidis
• Most frequently isolated organism
• Early PVE (w/i 60 days of surgery)
• Assoc. with valve dysfunction and fulminant
  clinical course
• Late PVE (beyond 60 days postop)
• Disease course is less fulminant
• Mycotic PVE (Aspergillus and Candida)
• Larger vegetations

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Clinical Features

• Acute IE Rapid onset of high fevers and rigors
  with hemodynamic deterioration and death within
  days to weeks if not treated
• Assoc. with highly virulent organisms such as
  Staph Aureus
• Subacute IE Indolent course with progressive
  constitutional signs and symptoms and gradual
  deterioration
• Assoc. with avirulent organisms such as viridans
  streptococci

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Clinical Features

• Bacteremia can produce signs and symptoms that
  are often nonspecific usually within 2 weeks of
  infection
• Most common course of disease (fevers, chills,
  nausea, vomiting, fatigue and malaise)
• Fever is the most common symptom
• Fever can be absent in pts with antibiotic use,
  antipyretic use, severe CHF, or renal failure
• Prosthetic valve patient with a fever requires
  IE work up

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Cardiac Clinical Features

• Heart murmurs are present in up to 85 of cases
  of IE.
• Most commonly regurgitant lesions secondary to
  valvular destruction
• Acute or progressive CHF is the leading cause of
  death in patients with IE (70 of patients)
• Distortion or perforation of valvular leaflets
• Rupture of the chordae tendinae or papillary
  muscles
• Perforation of the cardiac chambers (rare)
• Valvular abscesses and Pericarditis
• Heart blocks and Arrhythmias

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Embolic Clinical Features

• Extracardiac manifestations are the result of
  arterial embolization of fragments of the friable
  vegetation
• CNS complications occur in 20-40 of cases
  (embolic stroke with MCA affected most
  frequently)
• Retinal artery emboli may cause monocular
  blindness
• Mycotic aneurysm may cause a SAH
• IVDU can cause right sided lesions (tricuspid
  valve) Pulmonary complications
• Pulmonary complications ( pulmonary infarction,
  pneumonia, empyema, or pleural effusion)
• Coronary artery emboli (Acute MI or myocarditis
  with arrhythmias)
• Splenic infarction (LUQ abdominal pain)
• Renal emboli (flank pain or hematuria)

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Clinical Features

• Persistent bacteremia can stimulate the humoral
  and cellular immune systems resulting in
  circulating immune complexes
• Petechiae Red, nonblanching lesions that become
  brown after several days (20-40)
• Conjunctivae, buccal mucosa, and extremities
• Splinter hemorrhages Linear dark streaks under
  the fingernails (15)
• Oslers nodes Small tender subcutaneous nodules
  that develop on the pads of the fingers or toes
  (25)
• Janeway lesions Small hemorrhagic painless
  plaques located on the palms or soles
• Roth spots Oval retinal hemorrhages with pale
  centers located near the optic disc

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Diagnosis

• Diagnosis of IE requires hospitalization
• Cultures
• Echocardiogram
• Clinical observation
• Duke Criteria 90 sensitive
• Major Criteria
• Minor Criteria

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Major Criteria

• Positive blood culture for
• Strep bovis, Strep viridans, or HACEK group
• Staph aureus or Enterococci
• Microorganisms c/w IE from persistent positive
  blood cultures
• 2 positive blood cultures drawn gt12 hrs apart
• All of 3 or a majority of 4 or more positive
  blood cultures

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Major Criteria

• Echocardiographic involvement
• Mass on valve
• Abscess
• Dehiscence of prosthetic valve
• New valvular regurgitation

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Minor Criteria

• Predisposition Heart condition or injection drug
  use
• Fever gt 38 degrees C
• Vascular Emboli, conjunctival hemorrhages,
  janeway lesions
• Immunological Glomerulonephritis, oslers nodes,
  roth spots, and rheumatoid fever
• Positive blood cultures
• Echocardiographic findings c/w IE

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Duke Criteria

• Definite infective endocarditis
• Microorganisms demonstrated by culture or
  histologic examination of vegetation or emboli
• Abscess with active endocarditis
• Two major criteria
• One major and three minor criteria
• Five minor criteria
• Possible endocarditis
• Findings c/w IE that fall short of definite, but
  not rejected
• Rejected
• Firm alternate diagnosis
• Resolution of manifestations of IE with abx for lt
  4 days
• No pathologic evidence of IE at surgery or
  autopsy after 4 days of abx

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DDx and Consideration of IE

• IE should be considered in
• All febrile IDUs
• Pts with a cardiac prosthesis and fever (or
  malaise, vasculitis or new murmur)
• Pts with new murmur or change in murmur with
  evidence of vasculitis or embolization
• Any cardiac risk factor with unexplained fever
• Any patient with a prolonged fever (gt2 weeks)

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Evaluation of Bacteremia

• All patients with suspected bacteremia should
  have blood cultures drawn in the ED prior to abx
• Blood cultures should be drawn in 3 different
  sites
• Minimum of 10 ml blood in each bottle
• Minimum of one hour between first and last bottle

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Diagnostic Tests

• ECG should be done in all pts with suspected IE
• Nonspecific usually
• Conduction abnormalities ( new LBBB, Prolonged PR
  interval, new RBBB, complete heart block)
• Junctional tachycardia
• Chest Xray
• Pulmonic emboli or CHF
• Nonspecific lab tests
• Anemia (70-90 of cases)
• Elevated ESR (gt90 of cases)
• Hematuria

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Echocardiography

• Mandatory in all pts with possible IE
• Transthoracic Echo(TTE) should be done first.
• Specificity for vegetations is 98
• Sensitivity varies but it is the highest with
  IDUs because they more often have larger
  vegetations, right sided valvular lesions and
  favorable precordial windows.
• Transesophageal Echo(TEE) has a higher
  sensitivity and specificity than TTE
• Recommended for the following
• Prosthetic valves
• Pts with obesity, chest wall deformities, COPD
• Intermediate or high probability of IE

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Treatment

• Initial Stabilization
• Rapid airway stabilization secondary to possible
  respiratory or hemodynamic compromise( acidosis,
  altered mental status, sepsis)
• Cardiac decompensation may occur secondary to
  left sided valvular rupture
• Intraaortic balloon counterpulsation may be
  indicated
• Neurologic complications such as stroke
• Standard stroke protocol

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Empiric Treatment

• Therapy of suspected Bacterial Endocarditis
• Uncomplicated history
• Ceftriaxone or nafcillin plus gentamycin
• IVDU, Congenital heart disease, MRSA, current abx
  use
• Nafcillin plus gentamycin plus vancomycin
• Prosthetic heart valve
• Vancomycin plus gentamycin plus rifampin
• Most patients will require 4 to 6 weeks of
  antibiotic therapy

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Surgical Treatment

• Indications for surgical management
• Severe valvular dysfunction Acute CHF or
  impaired hemodynamic status
• Relapsing prosthetic valve endocarditis
• Major embolic complications
• Fungal endocarditis
• New conduction defects or arrhythmias
• Persistent bacteremia

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Anticoagulation

• Anticoagulation for native valve endocarditis has
  not been shown to be beneficial
• Increase the risk of intracranial hemorrhage
• Pts with prosthetic valves who are treated with
  anticoagulation can be maintained on their
  regimen with proper caution for CNS complications

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IE Prophylaxis

• Prophylaxis is indicated for
• Prosthetic heart valves
• Congenital cardiac manifestations
• Acquired valvular dysfunction
• Hypertrophic cardiomyopathy
• Mitral valve prolapse with documented
  regurgitation
• History of endocarditis
• Not indicated for the following
• MVP without regurgitation
• Pacemakers
• Physiologic murmurs
• Prior CABG, angioplasty, ASD repair, VSD, or PDA

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IE Prophylaxis

• Dental, oral, respiratory or esophageal
  procedures
• Amoxicillin or Ampicillin or Clindamycin
• Genitourinary, gastrointestinal procedures
• Ampicillin plus Gentamycin plus Ampicillin (post)
  or Amoxicillin
• Alternate regimen Vancomycin plus Gentamycin

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Question 1

• T/F Streptococcus is responsible for more than
  50 of Native Valve Endocarditis.

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Question 2

• Embolic clinical features of infective
  endocarditis include
• A) CNS complications
• B) Pulmonary complications
• C) Coronary Artery Emboli
• D) All of the above

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Question 3

• Small hemorrhagic painless plaques located on
  palms or soles are called?
• A) Janeway lesions
• B) Oslers nodes
• C) Roth Spots
• D) Splinter hemorrhages

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Answers

• 1) T
• 2) D
• 3) A