Download Infective endocarditis

Zoltán Péterfi
1st Department of Internal Medicine,
Dep. Infectology
Pécs
Definition
Infectious Endocarditis (IE): an infection of the
heart’s endocardial surface
 Classified into four groups:

 Native Valve IE
 Prosthetic Valve IE
 Intravenous drug abuse (IVDA) IE
 Nosocomial IE
Further Classification

Acute
 Affects normal heart




valves
Rapidly destructive
Metastatic foci
Commonly
Staphylococcus
If not treated, usually
fatal within 6 weeks

Subacute
 Often affects
damaged heart
valves
 Indolent nature
 If not treated, usually
fatal by one year
Infective Endocarditis
Febrile illness
 Persistent bacteremia
 Characteristic lesion of microbial infection of
the endothelial surface of the heart

the vegetation




Variable in size
Amorphous mass of fibrin & platelets
Abundant organisms
Few inflammatory cells
Pathophysiology
 Turbulent blood flow disrupts the
endocardium making it “sticky”
 Bacteremia delivers the organisms to
the endocardial surface
 Adherence of the organisms to the
endocardial surface
 Eventual invasion of the valvular
leaflets
Pathophysiology

Clinical manifestations
 Direct
○ Constitutional symptoms of infection (cytokine)
 Indirect
○ Local destructive effects of infection
○ Embolization – septic or bland
○ Hematogenous seeding of infection
- N.B. may present as local infection or persistent fever,
metastatic abscesses may be small, miliary
○ Immune response
- Immune complex or complement-mediated
Infective Endocarditis

Nonbacterial Thrombotic Endocarditis
Platelet-fibrin thrombi
- Endothelial injury
- Hypercoagulable state
 Lesions seen at coaptation points of valves
○ Atrial surface mitral/tricuspid
○ Ventricular surface aortic/pulmonic

Modes of endothelial injury
○ High velocity jet
○ Flow from high pressure to low pressure chamber
○ Flow across narrow orifice of high velocity
 Bacteria deposited on edges of low pressure sink or
site of jet impaction
Venturi Effect
Epidemiology
Incidence difficult to ascertain and varies
according to location
 Much more common in males than in females
 May occur in persons of any age and
increasingly common in elderly
 Mortality ranges from 20-30%

Risk Factors
Intravenous drug abuse
 Artificial heart valves and pacemakers
 Acquired heart defects

 Calcific aortic stenosis
 Mitral valve prolapse with regurgitation
Congenital heart defects
 Intravascular catheters

Infecting Organisms

Common bacteria
 S. aureus
 Streptococci
 Enterococci

Not so common bacteria
 Fungi
 Pseudomonas
 HACEK
Infective Endocarditis

Gram negative organisms
 P. aeruginosa most common
 HACEK - slow growing, fastidious organisms that
may need 3 weeks to grow out of culture
○ Haemophilus sp.
○ Actinobacillus
○ Cardiobacterium
○ Eikenella
○ Kingella
Symptoms

Acute
 High grade fever and chills
 Shortness of breath
 Arthralgias/ myalgias
 Abdominal pain
 Pleuritic chest pain
 Back pain

Subacute
 Low grade fever
 Anorexia
 Weight loss
 Fatigue
 Arthralgias/ myalgias
 Abdominal pain
 N/V
The onset of symptoms is usually ~2 weeks or less
from the initiating bacteremia
Signs
Fever
 Heart murmur
 Nonspecific signs – petechiae, subungal or
“splinter” hemorrhages, clubbing,
splenomegaly, neurologic changes
 More specific signs - Osler’s Nodes,
Janeway lesions, and Roth Spots

Petechiae
1. Nonspecific
2. Often located on extremities
or mucous membranes
dermatology.about.com/.../
blpetechiaephoto.htm
medicine.ucsd.edu/clinicalimg/ Eye-Petechiae.html
www.lib.uiowa.edu/ hardin/
md/cdc/3184.html
Splinter Hemorrhages
1. Nonspecific
2. Nonblanching
3. Linear reddish-brown lesions found under the nail bed
4. Usually do NOT extend the entire length of the nail
Osler’s Nodes
1. More specific
2. Painful and erythematous nodules
3. Located on pulp of fingers and toes
4. More common in subacute IE
Janeway Lesions
1. More specific
2. Erythematous, blanching macules
3. Nonpainful
4. Located on palms and soles
Roth’s Spots
The Essential Blood Test

Blood Cultures
 Minimum of three blood cultures
 Three separate venipuncture sites
 Obtain 10-20mL in adults and 0.5-5mL in children

Positive Result
 Typical organisms present in at least
2 separate samples
 Persistently positive blood culture (atypical organisms)
○ Two positive blood cultures obtained at least 12 hours apart
○ Three or a more positive blood cultures in which the first and
last samples were collected at least one hour apart
Additional Labs
CBC
 ESR and CRP
 Complement levels (C3, C4, CH50)
 RF
 Urinalysis
 Baseline chemistries and coags

Imaging

Chest x-ray
 Look for multiple focal infiltrates and
calcification of heart valves

EKG
 Rarely diagnostic
 Look for evidence of ischemia, conduction
delay, and arrhythmias

Echocardiography
Indications for Echocardiography

Transthoracic echocardiography (TTE)
 First line if suspected IE
 Native valves

Transesophageal echocardiography
(TEE)
 Prosthetic valves
 Intracardiac complications
 Inadequate TTE
 Fungal or S. aureus or bacteremia
ECHOCARDIOGRAPHY
 MAJOR findings:
 Vegetation
 Abscess
 Paraprosthetic
dehiscent
minor findings:
Fenestration
Fistula
Pseudoaneurysm
Rupture (tendon, valve)
TTE
NVIE PVIE
TEE
NVIE PVIE
sensitivity
specificity
50%
78%
sensitivity
specificity
100%
89%
17%
94%
83%
95%
23
24
Making the Diagnosis

Pelletier and Petersdorf criteria (1977)
 Classification scheme of definite, probable, and possible IE
 Reasonably specific but lacked sensitivity

Von Reyn criteria (1981)
 Added “rejected” as a category
 Added more clinical criteria
 Improved specificity and clinical utility

Duke criteria (1994)
 Included the role of echocardiography in diagnosis
 Added IVDA as a “predisposing heart condition”
Modified Duke Criteria

Definite IE
 Microorganism (via culture or histology) in a valvular vegetation,
embolized vegetation, or intracardiac abscess
 Histologic evidence of vegetation or intracardiac abscess

Possible IE
 2 major
 1 major and 3 minor
 5 minor

Rejected IE
 Resolution of illness with four days or less of antibiotics
Treatment

Parenteral antibiotics
 High serum concentrations to penetrate
vegetations
 Prolonged treatment to kill dormant bacteria
clustered in vegetations

Surgery
 Intracardiac complications

Surveillance blood cultures
Antibiotic therapy

Streptococci (alfa haemolytic):
 Penicillin susceptible viridans or S. bovis (MIC<1 mg/l)
○ penicillin or ceftriaxon 4 weeks
○ penicillin + aminoglycoside 2 weeks
 Intermediate susceptible streptococci (MIC >1 mg/l)
○ penicillin vagy ceftriaxon 4-6 weeks+ aminoglicoside 2 weeks
○ vancomycin/teicoplanin 4-6 weeks (beta-lactame intolerance)
28
 Enterococci
 No bactericidic antibiotics  combination!!
 Penicillin, aminoglicoside, vancomycin susceptible
○ penicillin G or Ampicillin + gentamycin 4-6 weeks
○ vancomycin + gentamycin
4-6 weeks
 Penicillin allergic, vancomycin rezistant strains
○ teicoplanin + gentamycin
4-6 weeks
 Penicillin rezistant (MIC> 8 mg/l)
○ vancomycin + gentamycin
4-6 weeks
○ amoxicillin/calvulanic acid + gentamycin4-6 weeks
29
 Staphylococci
 NVIE methicillin susceptible
○ oxacillin or cefazolin + gentamycin
○ vancomycin
4-6 weeks
4-6 weeks
 NVIE methicillin rezistant
○ vancomycin
4-6 weeks
 PVIE methicillin susceptible
○ oxacillin + rifampicin + gentamycin
6 weeks
 PVIE methicillin rezistant
○ vancomycin + rifampicin + gentamycin 6 weeks
30
Complications
Embolic
 Local spread of infection
 Metastatic spread of infection
 Formation of immune complexes –
glomerulonephritis and arthritis

Embolic Complications
Occur in up to 40% of patients with IE
 Predictors of embolization

 Size of vegetation
 Left-sided vegetations
 Fungal pathogens, S. aureus, and Strep.
bovis

Incidence decreases significantly after
initiation of effective antibiotics
Embolic Complications
Stroke
 Myocardial Infarction

 Fragments of valvular vegetation or
vegetation-induced stenosis of coronary
ostia
Ischemic limbs
 Hypoxia from pulmonary emboli
 Abdominal pain (splenic or renal
infarction)

Septic Pulmonary Emboli
Septic Retinal Embolus
Local Spread of Infection

Heart failure
 Extensive valvular damage

Paravalvular abscess (30-40%)
 Most common in aortic valve, IVDA, and S. aureus
 May extend into adjacent conduction tissue causing
arrythmias
 Higher rates of embolization and mortality
Pericarditis
 Fistulous intracardiac connections

Local Spread of Infection
Acute S. aureus IE with perforation of the
aortic valve and aortic valve vegetations.
Acute S. aureus IE with mitral valve ring
abscess extending into myocardium.
Metastatic Spread of Infection

Metastatic abscess
 Kidneys, spleen, brain, soft tissues
Meningitis and/or encephalitis
 Vertebral osteomyelitis
 Septic arthritis

Poor Prognostic Factors






Female
S. aureus
Vegetation size
Aortic valve
Prosthetic valve
Older age






Diabetes mellitus
Low serum albumin
Apache II score
Heart failure
Paravalvular abscess
Embolic events
Prevention

Prophylactic regimen targeted against likely
organism
 Strep. viridans – oral, respiratory, eosphogeal
 Enterococcus – genitourinary, gastrointestinal
 S. aureus – infected skin, mucosal surfaces
Prevention – the underlying lesion

High risk lesions

Intermediate risk
 Prosthetic valves
 MVP with murmur
 Prior IE
 Pure MS
 Cyanotic congenital heart
 Tricuspid disease





disease
PDA
AR, AS, MR,MS with MR
VSD
Coarctation
Surgical systemicpulmonary shunts
Lesions at highest risk
 Pulmonary stenosis
 ASH
 Bicuspid Ao valve with no
hemodynamic significance
Chemoprophylaxis
Adult Prophylaxis: Dental, Oral, Respiratory, Esophageal
Standard Regimen
Amoxicillin 2g PO 1h before procedure or
Ampicillin 2g IM/IV 30m before procedure
Penicillin Allergic
Clindamycin
600 mg PO 1h before procedure or
600 mg IV 30m before
Cephalexin OR Cefadroxil 2g PO 1 hour before
Cefazolin 1.0g IM/IV 30 min before procedure
Azithromycin or Clarithromycin 500mg PO 1h before
Adult Genitourinary or Gastrointestinal Procedures
High Risk Patients
Standard Regimen
Before procedure (30 minutes):
Ampicillin 2g IV/IM AND
Gentamicin 1.5 mg/kg (MAX 120 mg) IM/IV
After procedure (6 hours later)
Ampicillin 1g IM/IV OR
Amoxicillin 1g PO
Penicillin Allergic
Complete infusion 30 minutes before procedure
Vancomycin 1g IV over 1-2h AND
Gentamycin 1.5 mg/kg IV/IM (MAX 120 mg)
Moderate Risk Patients
Standard Regimen
Amoxicillin 2g PO 1h before OR
Ampicillin 2g IM/IV 30m before
Penicillin Allergic
Vancomycin 1g IV over 1-2h, complete 30m before