Micro - Endocarditis Flashcards
What are the most common procedures causing endocarditis?
Oral and dental
What are some of the risk factors for endocarditis?
Men more than women Age increasing (half over 50) Native valve - calcific aortic stenosis, rheumatic, congenital defects, mitral valve prolapse Prosthetic valve IV drug use Nosocomial
What is the pathogenesis of endocarditis?
Damage endothelium in high flow stress areas
Deposition of fibrin and platelets (nonbacterial thrombotic endocarditis)
Stasis on downstream side of lace
Transient bacteremia - adhesiveness, colonize thrombus
What is the role of strep in infective endocarditis?
Viridans about 50% - affects Pre existing heart disease and *follows dental procedures since part of oral flora
Enterococci - often with GI or GU path/procedures
S. bovis - *associated with colon cancer
Pneumococcus is rare
What is the role of staph in infective endocarditis?
S. aureus - *major pathogen in IVDA, also line associated complication and cardiac surgery complication
Coagulase negative - cardiac surgery, complication of line infections
What is culture negative endocarditis?
*most common cause is prior antibiotic therapy
Bartonella, chlamydia, rickettsia, brucella, HACEK organisms, coxiella, fungi
What are the HACEK organisms?
Haemophilus aprophilus and others Actinobacillus actinomycetemcomitans (a haemophilus) Cardiobacterium hominis Eikenella corrodens Kingella kingae *gram negative (oral flora) *slow growing Require high CO2
What is the role of bartonella in endocarditis?
Small, gram negative rods
B. henselae (flea-borne) and b. Quintana (louse)
*associated with homelessness and alcoholics
85% with prior valvular disease
40% with systemic emboli
What is fungal endocarditis?
Increasing frequency in IVDA, patients with IV lines, immunocompromised
Large vegetations and embolisms
Negative cultures common in past but not anymore
Near universal requirement for valve replacement
What is IVDA associated endocarditis?
*s. aureus most common
MRSA much more common than MSSA
Gram negative rod (pseudomonas aeruginosa and others)
Fungi
*tricuspid valve most commonly involved - septic emboli to lungs common
What is the difference between acute and subacute endocarditis?
Acute - acute onset, high fever, rigors, leukocytosis, CHF, s. aureus most, IVDA, early prosthetic valves, metastatic infections
Subacute - insidious onset, lower fever, weight loss, malaise, fatigue, viridans strep and HACEK and enterococci, rheumatic valves, late prosthetic valves, dental procedures, has peripheral signs
What are peripheral signs of endocarditis?
Janeway lesions - painless, more frequent with acute and a. Aureus, small red circles on palms and soles
Osler nodes - painful, pulpy parts of toes and fingers, bigger darker splotches
Splinter hemorrhages - under nails
Roth spots - on retina in viridans strep
Conjunctival petechiae
Mycotic aneurysms in cerebral circulation
What is a bio prosthetic valve?
Valve ring is prosthetic
Valve is porcine or bovine
What is prosthetic valve endocarditis and what are the risk factors for it?
Early (*think CONS) better than late
Risk factors - operation during ongoing infection, duration of surgery, number of valves replaced, aortic more than mitral, elderly men, type of valve not important
What are some complications of endocarditis?
1/3 to 1/2 of patients
Cardiac - abscesses, conduction abnormalities (usually from aortic valve, heart blocks), CHF, pericarditis
Systemic - strokes, mycotic aneurysms
What are the four criteria for diagnosis of endocarditis?
Predisposition and clinical syndrome
Bacteremia
Evidence of cardiac involvement
Vascular phenomenon
How are blood cultures used in endocarditis?
Key feature is constant level of bacteremia
Usually low
3 sets over 24 hr most sensitive
Serology - use for Q fever, bartonella
What kinds of echocardiography can be used to assess endocarditis?
Transthoracic - less invasive, less expensive, doesn’t see structures as well
Transesophageal - more invasive, more sensitive, *better at evaluating prosthetic valves, detects smaller vegetations and intramyocardial abscesses
What are the major criteria for diagnosing endocarditis?
Blood cultures
Echo - vegetation, abscess, dehiscence of prosthetic valve, new regurgitant murmur
What are the minor criteria for diagnosing endocarditis?
Fever Embolic phenomenon Immunological phenomenon Serological evidence of organisms Microbiological and echocardiographic criteria that do not meet major criteria
How can the duke criteria be interpreted?
Definite - pathological, clinical (2 major, 1 major and 3 minor, 5 minor)
Possible
Rejected - alternative diagnosis, resolution in four days or less of antibiotics, no pathologic evidence at surgery or autopsy with less than four days antibiotics
What are the main ways to treat endocarditis?
Antibiotics
Surgery
Manage cardiac complications - CHF, arrhythmias
Avoid anti coagulation
How are antibiotics used in the treatment of endocarditis?
*bactericidal IV admin High doses Synergistic combos *prolonged duration - minimum 4-6 weeks
What are surgical indications in endocarditis?
Persistent bacteremia despite antibiotics Prosthetic valve or fungal Abscess of annulus or myocardium Refractory CHF due to valve failure Vegetations >10 mm Multiple systemic emboli
How should one try to prevent endocarditis?
Only in high risk patients
Should admin at least one hour before procedure
Dental, oral, or upper respiratory procedures
What factors influence the rates of catheter related bloodstream infections?
Site of central line - internal jugular = femoral > subclavian
Central more than periphery
Conventional tip more than antibiotic or silver impregnated
Dialysis more than all others
Non tunneled more than tunneled more than implanted
Hyperalimentation more than other solutions
What kinds of organisms are involved in catheter related bloodstream infections?
Usually skin flora
Coagulase negative staph more than s. aureus = 50%
GNRs = 25%
Candida = 20%
Other skin flora - diphtheroids, propionibacteria, bacillus
What is the treatment for catheter related bloodstream infections?
Remove the line
Antibiotics directed against most likely organisms or isolated organisms
Duration - 5-14 days if line is out, two weeks if line is in
What is myocarditis and which organisms are responsible for it?
Inflammation of muscular layer of heart
Non specific febrile syndrome with arrhythmias or signs and symptoms of CHF
Most infections probably viral - Lyme, t. Cruzi
Adenovirus and entero virus - echovirus, coxsackie b virus
Direct invasion of myocytes and immune reaction to infected myocytes
What are the risk factors for myocarditis and how is it diagnosed?
Men more than no pregnant women, pregnancy and immunocompromised
Forced exercise, pregnancy, use of steroids or NSAIDs worsens prognosis, alcohol, nutritional deficiencies
*definitive diagnosis requires myocardial biopsy
Echo and EKG for cardiac consequences
What is pericarditis?
Inflammation of pericardium
Most infections are viral, also noninfectious forms
Fever, myalgia, malaise
Acute onset of sharp, sub sternal chest pain worse with supine and inspiration
Friction rub
Diagnose with echo and EKG
Treatment = NSAIDs, corticosteroids, colchicine
