Micro - Endocarditis

Question 0

What are the most common procedures causing endocarditis?

Answer 0

Oral and dental

Question 1

What are some of the risk factors for endocarditis?

Answer 1

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

Question 2

What is the pathogenesis of endocarditis?

Answer 2

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

Question 3

What is the role of strep in infective endocarditis?

Answer 3

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

Question 4

What is the role of staph in infective endocarditis?

Answer 4

S. aureus - *major pathogen in IVDA, also line associated complication and cardiac surgery complication
Coagulase negative - cardiac surgery, complication of line infections

Question 5

What is culture negative endocarditis?

Answer 5

*most common cause is prior antibiotic therapy

Bartonella, chlamydia, rickettsia, brucella, HACEK organisms, coxiella, fungi

Question 6

What are the HACEK organisms?

Answer 6

Haemophilus aprophilus and others
Actinobacillus actinomycetemcomitans (a haemophilus)
Cardiobacterium hominis
Eikenella corrodens
Kingella kingae
*gram negative (oral flora)
*slow growing
Require high CO2

Question 7

What is the role of bartonella in endocarditis?

Answer 7

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

Question 8

What is fungal endocarditis?

Answer 8

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

Question 9

What is IVDA associated endocarditis?

Answer 9

*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

Question 10

What is the difference between acute and subacute endocarditis?

Answer 10

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

Question 11

What are peripheral signs of endocarditis?

Answer 11

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

Question 12

What is a bio prosthetic valve?

Answer 12

Valve ring is prosthetic

Valve is porcine or bovine

Question 13

What is prosthetic valve endocarditis and what are the risk factors for it?

Answer 13

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

Question 14

What are some complications of endocarditis?

Answer 14

1/3 to 1/2 of patients
Cardiac - abscesses, conduction abnormalities (usually from aortic valve, heart blocks), CHF, pericarditis
Systemic - strokes, mycotic aneurysms

Question 15

What are the four criteria for diagnosis of endocarditis?

Answer 15

Predisposition and clinical syndrome
Bacteremia
Evidence of cardiac involvement
Vascular phenomenon

Question 16

How are blood cultures used in endocarditis?

Answer 16

Key feature is constant level of bacteremia
Usually low
3 sets over 24 hr most sensitive
Serology - use for Q fever, bartonella

Question 17

What kinds of echocardiography can be used to assess endocarditis?

Answer 17

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

Question 18

What are the major criteria for diagnosing endocarditis?

Answer 18

Blood cultures

Echo - vegetation, abscess, dehiscence of prosthetic valve, new regurgitant murmur

Question 19

What are the minor criteria for diagnosing endocarditis?

Answer 19

Fever
Embolic phenomenon
Immunological phenomenon
Serological evidence of organisms
Microbiological and echocardiographic criteria that do not meet major criteria

Question 20

How can the duke criteria be interpreted?

Answer 20

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

Question 21

What are the main ways to treat endocarditis?

Answer 21

Antibiotics
Surgery
Manage cardiac complications - CHF, arrhythmias
Avoid anti coagulation

Question 22

How are antibiotics used in the treatment of endocarditis?

Answer 22

*bactericidal
IV admin
High doses
Synergistic combos
*prolonged duration - minimum 4-6 weeks

Question 23

What are surgical indications in endocarditis?

Answer 23

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

Question 24

How should one try to prevent endocarditis?

Answer 24

Only in high risk patients
Should admin at least one hour before procedure
Dental, oral, or upper respiratory procedures

Question 25

What factors influence the rates of catheter related bloodstream infections?

Answer 25

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

Question 26

What kinds of organisms are involved in catheter related bloodstream infections?

Answer 26

Usually skin flora
Coagulase negative staph more than s. aureus = 50%
GNRs = 25%
Candida = 20%
Other skin flora - diphtheroids, propionibacteria, bacillus

Question 27

What is the treatment for catheter related bloodstream infections?

Answer 27

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

Question 28

What is myocarditis and which organisms are responsible for it?

Answer 28

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

Question 29

What are the risk factors for myocarditis and how is it diagnosed?

Answer 29

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

Question 30

What is pericarditis?

Answer 30

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