Endocarditis

Question 1

The vegetations of endocarditis are composed of what substances?

What aspects of the heart are most commonly affected by endocartidis?

What are the classifications of the disease?

Epidemiology?

Answer 1

• Vegetation
  
  • mass of platelets, fibrin, inflammatory cells, and microcolonies of macroorganisms
• Most commonly incolves the heart valves
  
  • low pressure side of VSD
  • intracardiac devices
  • damaged endocardium
• Classified by evolution of the disease
  
  • acute
    
    • rapid damage, rapid progression to death within weeks
  • subacute
    
    • indolent course, rarely metastasizes, causes slow damage if any at all
    • major complications are embolization and ruptured mycotic aneurysms
• Epidemiology
  
  • 4-7 (11-15) cases per 1000,000 population

Question 2

What are the 12 risk factors for endocarditis?

Answer 2

• history or prior endocarditis
• presence of a prosthetic valve or device
  
  • stent in an artery is NOT a risk factor
• valvular heart disease
• congenital heart disease
• intravenous drug abuse (organisims & valves are different)
• indwelling intravenous catheters/intracardiac devices
• Rheumatic heart disease-in developing countries
• immunosuppression
• recent dental or surgical procedure (bacteremia is a risk)
• men > women
• age > 60
• poor dentition or dental infection

Question 3

Etiological causes of endocarditis?

Answer 3

• Oral cavity, skin, upper respiratory tract are primary portals
  
  • strep and staph
  • HAECK organisms (v. slow growing)
    
    • Haemophilus species
    • Aggregatibacter aphrorophilus
    • Aggregatibacter actinomycetemcomitans
    • Cariobacterium species
    • Eikenella species
    • Kingella species
• Also GI tract - patient has colon cancer until proven otherwise
  
  • strep gallolyticus (formerly S. bovis)
• GU tract
  
  • enterococcus species (VRE is a concern)
• Prosthetic valve endocarditis
  
  • usually first 3 months after surgery
  • nosocomial organisms
• pacemaker/defibrillator wires

Question 4

Common etiological causes of nosocomial endocarditis?

What is the criteria for something to be considered nosocomial?

How are they often acquired?

Answer 4

• Etiological causes
  
  • MSSA and MRSA
  • coagulase-negative staphylococci (CoNS)
  • enterococci
• health care contact within preceeding 90 days
• Acquired
  
  • Complicates 6-25% of catheter associated blood stream infectiosn (S. aureus)
  • Prosthetic valve endocarditis
    
    • within 2 months-nosocomial
      
      • intraoperative inocculation
      • S. aureus, CoNS, diptheroids, facultative gram negative bacilli
    • after 12 months-same portal of enter as other causes (no longer considered nosocomial)

Question 5

What valve is most commonly affected in endocarditis caused by IV drug use?

What is the most commonly associated etiological agent?

What is a common complication?

How does it present?

Answer 5

• Tricuspid valve
• S. aureus (often MRSA)
• embolization to lung
  
  • no peripheral manifestations
• presents with fever
  
  • faint or no murmur
  • cough
  • pleuritic chest pain
  • nodular infiltrates

Question 6

Describe the pathogenesis of endocarditis

Endocarditis can cause what conditions?

Answer 6

• Develops at sights of endothelial injury
  
  • impact of high velocity jets
  • low pressure side of cardiac structural lesions
• Most cases will be nonbacterial thrombitic endocarditis
  
  • platelet-fibrin thrombus can serve as a sight for bacterial attachment
  • virulent bacteria can adhere directly to intact endothelium
• Most common conditions
  
  • mitral regurgutation
  • aortic stenosis
  • aortic regurgitation
  • VSD and congenital heart disease
• Organism enter the blood stream through portals of entry
  
  • mucosal membranes, skin, areas of focal infection
• organisms deep in the vegetation are metabolically inactive
• surgace organisms are proliferating and shed into the blood stream

Question 7

What are the clinical features (symptoms) of endocarditis?

Answer 7

• fever 80-90%
• chills and sweats, 40-75%
• anorexia, weight loss, malaise, 25-50%
• myalgias
• back pain
• new murmur, 80-85%
• arterial emboli, 20-50%
• petechiae, 10-40%

Question 8

What laboratory abnormalities are associated with endocarditis?

Answer 8

• anemia
• leukocytosis
• microscopic hematuria
• elevated sed rate
• elevated CRP
• posisitve rheumatoid factor
• circulating immune complexes (don’t really test for it)
• decreased complement

Question 9

What are the cardiac clinical manifestations associated with endocarditis?

Answer 9

• valvular damage leads to new murmurs
• ruptured chordea
• heart failure s/s in 30-40%
• possible conduction delays
• pericarditis if it erodes through valve annulus

Question 10

What are the non-cardiac clinical minifestations of endocarditis?

Answer 10

• Nonsuppurative (janeway lesions)
  
  • have become infrequent due to earlier diagnosis and treatment
  • Roth spots - exudative, edematous hemorrhagic lesion of the retina with pale center
  • Janeway lesions-Microabscess of the dermis
    
    • non-tender macules on palms and soles
  • Osler’s nodes-immunocomplex deposits
    
    • tender subcutaneous nodules on pads of fingers adn toes
• Nonspecific musculoskeletal pain
• Embolization
  
  • subungual (under a nail) hemorrhage
  • lesions > 10 mm more likely (Especiall S. aureus)
  • Septic emboli to brain

Question 11

What tests can be performed to diagnose endocarditis?

Answer 11

• Duke criteria (major & minor)
• Blood cultures
  
  • critical for diagnosis
  • three 2 bottle cultures
    
    • 2 hours apart
    • different sites
    • repeat in 48-72 hours if negative
• Blood tests
  
  • CBC, Cr. electrolytes, liver function tests, sed rate
• Echocardiography
• telemetry monitoring

Question 12

Name the major & minor Duke’s criteria for endocarditis

How many of each indicates a diagnosis?

Answer 12

• 2 major OR 1 major / 3 minor OR 5 minor
• Major Criteria
  
  1. persistantly positive blood culture for typical organism
     
     • Viridans streptococci
     • S.gallolyticus (old bovis)
     • HACEK group
     • S. aureus
     • Enterococus
     • S. epidermidis (prosthetic valve only)
  2. Provide ECHO for vegetation, root abscess or dehiscence of prosthetic valve
     
     • TTE usually
     • TEE for prosthetic valves
  3. New regurgitant murmur
  4. single positive blood culture for C. burnetii or serology > 1:800
• Minor Criteria
  
  1. Fever
  2. presence predisposting valvular condition or IV drug use
     
     • prosthetic heart valve
     • valve lesion that leads to significant regurgitation
     • turbulence of blood flow
  3. vascular phenomenen
     
     • emboli to organs or brain
     • hemorrhages in mucus membranes around eyes
  4. Immunologic phenomenon
     
     • glomerulonephritis
     • lesions such as Roth’s spots (inretina)
     • Osler’s nodes (nodules on fingers/toes)
  5. Positive blood cultures that do not meet the strict definitions of a major criteria

Question 13

Check this out (DRAW this decision tree)

Question 14

What is the purpose of performing an echocardiogram when diagnosing endocarditis?

What is the difference between a TTE and a TEE?

Answer 14

• Reason
  
  • Confirms lesion & identifies location
    
    • perivalvular abscess or rupture
  • measure size
• Transthoracic echocardiogram (TTE) vs Transesophageal echocardiogram (TEE)
  
  • TTE cannot see lesions <2mm
  • Technically difficult in COPD
  • TEE looks for paravalvular abscess, significant regurgitation to determien need for surgery
  • TEE- for go TTE in prosthetic valves or intracardiac device
• Echo required for any patient with S. aureus bacteremia

Question 15

What is the treatment for endocarditis?

Answer 15

• Early empiric treatment
• Difficult location to eradicate bacteria
  
  • metabolically inactive
  • local host defenses are deficient
• long term antimicrobial therapy
  
  • usually 6 weeks IV for duration
• removal of implanted devices
• surgical treatment
  
  • big on L side of heart

Question 16

Describe the empiric therapy for endocarditis

Answer 16

• started before cultures are known (or negative)
• bactericidal antibiotics are required
• use clinical clues
  
  • IV drug user- cover MRSA and gram negative
  • health care associated- must cover for MRSA
  • consider HACE organisms when culture negative
• CUlture negative prosthetic valve (PVE)- vancomycin, gentamicin, cefepime, rifampin if valve in place < 1 year
• PVE > 1 year, treat like other culture negative endocarditis

Question 17

What are indications for surgical treatment for endocarditis?

Answer 17

• Indications
  
  • HF caused by worsening valve dysfunction
  • perivalvular infection (10-15% of native valves, 45-60% of prosthetic valves)
    
    • new electrical disturbance, pericarditis, persistent unexplained fever
  • uncontrolled infectin
  • S. aureus
    
    • decrease in mortality from 50-25% in patient with PVE
    • consider in native valve disease in patients who remain septic after initial week of treatment
  • prevent systemic emboli
    
    • vegetation size, > 1cm requires surgery

Question 18

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Question 19

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