Infective Endocarditis Flashcards
Vegetation
Mass of platelets, fibrin, inflammatory cells, and microcolonies of
microrganisms
Most commonly involves the heart valves
► Low pressure side of VSD
► Intracardiac devices
► Damaged endocardium
Endocarditis Classification
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 aneurysm
Risk Factors of Endocarditis
► History of prior endocarditis ► *Presence of a prosthetic valve or device ► *Vavlular heart disease ► Congenital heart disease ► *Intravenous drug abuse ► *Indwelling intravenous catheters/intracardiac devices ► Rheumatic heart disease-in developing countries ► Immunosuppression ► Recent dental or surgical procedure ► Men>women ► Age>60 ► Poor dentition or dental infection
Etiology
► Many species of bacteria and fungi
► Really only a few cause the majority of cases
► Oral cavity,skin, upper respiratory tract are primary portals
► Strep and staph
► HACEK organisms
► Also GI tract
► Strep gallolyticus (formerly S. bovis)
► GU tract
► Enterococcus species
► Prosthetic valve endocarditis
► Usually first 3 months after surgery
► Nosocomial organisms
► Pacemaker/Defibrillator wires
HACEK Organisms
► Haemophilus species
► Aggregatibacter aphrorophilus
► Aggregatibacter actinomycetemcomitans
► Cardiobacterium species
► Eikenella species
► Kingella species
Nosocomial
Staphyloccus aureus
► MSSA and MRSA
Coagulase-negative staphylococci (CoNS)
Enterococcci
Health care contact within preceeding 90 days
Complicates 6-25% of catheter associated blood stream infections (S.
aureus)
Prosethic 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
IV drug use
► 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
Pathogensis
Develops at sights of endothelial injury
► Impact of high velcity jets
► Low pressure side of cardiac structural lesions
Nonbacterial thrombitic endocarditis
► Platelet-fibrin thrombus can serve as a sight for bacterial attachment
► Virulent bacterial can adhere directly to intact endothelium
Most common conditions ► Mitral regurgitation ► 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
Surface organisms are proliferating and shed into the blood steam
Clinical Features
► Fever, 80-90%
► Chills and sweats, 40-75%
► Anorexia, weight loss,
malaise, 25-50%
► Mylagias
► Back Pain
► New Murmur, 80-85%
► Arterial emboli, 20-50%
► Petechiae, 10-40%
Lab Adnormalities
► Anemia
► Leukocytosis
► Microscopic hematuria
► Elevated sed rate
► Elevated CRP
► Positive Rheumatoid factor
► Circulating immune complexes
► Decreased complement
Clinical Manifestations
► 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
Non Cardiac Manifestations
► Nonsuppurative (Janeway lesions)
► Nonspecific musculoskeletal pain
► Embolization
Nonsuppurative (Janeway Lesions)
► Have become infrequent due to earlier diagnosis and treatment
► Roth spots- exudative, edematous hemorrhagic lesion of the retina with
pale center
► Microabscess of the dermis
► Non-tender macules on palms and soles
Osler’s Nodes
Immunocomlpex deposits
tender subQ nodules on pads of fingers and toes
Embolization
► Subungual hemorrhage
► Lesions >10mm more likely (Especially S. aureus)
► Septic emboli to brain
Diagnosis
Duke Criteria
Blood Cultures
Blood Tests
Echocardiography
Telemetry Monitoring
Duke Criteria
2 major; 1 major & 3 minor; 5 minor
Blood Cultures
Critical to Dx
3- 2 bottle cultures
- 2 hrs apart
- different sites
- repeat in 48-72 hrs if negative
Blood Tests
CBC Cr Electrolytes LFT Sed rate
Echocardiogram
Confirms lesion
Identifies location
► Perivavlular abscess or rupture
Measure size
TTE vs TEE
► TTE cannot see lesions <2mm
► Technically difficult in COPD
► TEE-look for paravalvular abscess, significant regurgitation to determine
need for surgery
► TEE- for go TTE in prosthetic valves or intracardiac device
Staph aureus bacteremia
Treatment
Early empiric treatment
Difficult location to eradicate bacteria
► Metabolically inactive
► Local host defenses are deficient
Long term antimicrobial therapy
► Usually IV for duration
Removal of implanted devices
Surgical Treatment
Empiric Therapy
► 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 HACEK 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
Surgical Treatment Indications
► HF caused by worsening valve dysfucntion
► Perivalvular infection (10-15% of native valves, 45-60% of prosthetic valves)
► New electrical disturbance, pericarditis, persistent unexplained fever
► Uncontrolled infection
► S. aureus
► Decrease in mortality from 50-25% in patients with PVE
► Consider in native valve disease in patients who remain septic after initial week
of treatment
► Prevent systemic emboli
► Vegetation size, >1 cm requires surgery
► Implantable devices
