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Infective Endocarditis  

Title               

Ñ    Infective Endocarditis (IE)

Definition

Ñ    Infection of the endocardial surface of the heart

Types

Ñ    Sub Acute Infective Endocarditis

 Infection of a pre-existing cardiac lesion

Ñ    Acute Infective Endocarditis

 Infection of a previously normal heart valve

Ñ    Prosthetic Valve Endocarditis

Infection of a prosthetic valve

Ñ    Nosocomial Endocarditis

Infection within 48 hours of hospitalisation or within 4 weeks of a procedure being   performed

This may be:

·          Right sided:

Normal valve, procedure related

·          Left sided:

Pre-existing cardiac lesion

Ñ    Pacemaker Endocarditis

Within a few months of implantation:

·          Generator pocket

·          Proximal leads

·          Lead in contact with endocardium

Pathogenesis

Lesions

Ñ    Rheumatic valvular disease

Ñ    Calcific aortic stenosis

Ñ    Bicuspid aortic valve

Ñ    Ventricular septal defect

Ñ    Patent ductus arteriosus

Ñ    Tetralogy of Fallot

Ñ    Mitral valve prolapse

Ñ    Prosthetic valve

Organisms

Ñ    Streptococci:

Streptococcus viridans

Streptococcus intermedius group

Nutritionally variant streptococci

Group D streptococci

Nonenterococcal group D organisms

Group B streptococci

Group A, C, and G streptococci

Ñ    Staphylococci:

Staphylococcus aureus

Coagulase-negative S aureus

Ñ    Pseudomonas aeruginosa

Ñ    HACEK organisms:

Haemophilus aphrophilus

Actinobacillus actinomycetemcomitans

Cardiobacterium hominis

Eikenella corrodens

Kingella kingae

Ñ    Fungi:

Candida parapsilosis

Candida tropicalis

Aspergillus

Ñ    Bartonella species:

·          Bartonella:

Culture-negative endocarditis

Homeless

Ñ    Polymicrobial IE:

·          Pseudomonas and enterococci:

Most common combination in intravenous drug abuse (IVDA)

Culture-negative IE

Ñ    Non-infectious:

Vasculitis

Ñ    Fastidious organisms:

Nutritionally variant streptococci

Ñ    Prior use of antibiotics

Ñ    Coxiella burnetii

Ñ    Bartonella species:

Among homeless persons

Ñ    Fungal infections:

Often sterile

Ñ    S aureus:

Burrow deep within thrombus, sequestered

Prosthetic valve endocarditis

Ñ    Early prosthetic valve endocarditis:

·          Less than 1 year after surgery:

Usually due to contamination during surgery

Most common organism is Staphylococcus epidermidis

Ñ    Late prosthetic valve endocarditis:

Haematogenous spread

Most common cause is Streptococcus viridians

There are different views as to the cut off point for dividing into early and late prosthetic valve endocarditis (PVE) some authorities say 60 days and others say 6 months

Pathological Process

Ñ    Bacteraemia

Ñ    Non-infectious thrombotic endocarditis

Ñ    Adherence of organisms to this area

Ñ    Multiplication of organisms

Ñ    Further platelet aggregation and thrombosis

Complications

Ñ    Local effects:

Valve destruction

Paravalvular abscess

Ñ    Embolisation

Ñ    Immune phenomena

Clinical Features

History

Age

Ñ    Any age

Ñ    Frequency increasing in the elderly

Sex

Ñ    Males > Females

E&M

Ñ    Fever

Ñ    Fatigue

Ñ    Weight loss

Ñ    High fever with chills:

Acute IE

CVS

Ñ    Congestive heart failure:

More common in acute IE

GIT

Ñ    Anorexia

CNS

Ñ    Stroke

LMS

Ñ    Back pain

Examination

E&M

Ñ    Fever

IS

Ñ    Clubbing

Ñ    Splinter haemorrhages

Ñ    Osler’s nodes

Ñ    Janeway lesions

CVS

Ñ    Features of underlying cardiac lesion

RS

Ñ    Pulmonary infarcts:

Right-sided endocarditis

Ñ    Lung abscess:

Right-sided endocarditis

Ñ    Empyema:

Right-sided endocarditis

HS

Ñ    Splenomegaly

CNS

Ñ    Meningitis

Ñ    Embolic phenomena

Ñ    Roth spots:

Retinal haemorrhages

Complications

CVS

Ñ    Valve dehiscence

Ñ    Paravalvular abscess

GIT

Ñ    Rupture of a hepatic artery mycotic aneurysm:

Haematemesis, jaundice

Ñ    Rupture of a mycotic aneurysm into small or large bowel:

Bloody diarrhoea

KUS

Ñ    Rupture of a renal mycotic aneurysm:

Hypertension and haematuria

HS

Ñ    Splenic abscess:

Rare complication

CNS

Ñ    Intracranial mycotic aneurysm:

·          Presents as a mass lesion or an embolic event:

Severe localized headache

Altered sensorium

Focal neurological deficit

LMS

Ñ    Septic arthritis

Investigations

Fluids

Blood

Haematology

Ñ    Normocytic normochromic anaemia

Ñ    Plasma viscosity :

Elevated

Biochemistry

Ñ    C-reactive protein:

Elevated

Immunology

Ñ    Coxiella burnetii

Ñ    Chlamydia

Ñ    Brucella

Ñ    Legionella

Microbiology

Ñ    Blood cultures positive

Urine

Haematology

Ñ    Microscopic haematuria

Imaging

Ultrasound

Ñ    Echocardiogram:

Vegetations

Abscesses

Valve dehiscence

New regurgitation

Ñ    Transoesophageal echocardiogram:

More sensitive

CT Scan

Ñ    Embolic phenomena

Ñ    Abscesses

Ñ    Mycotic aneurysm

MRI

Ñ    Mycotic aneurysm

Electrophysiology

ECG

Ñ    Intraventricular conduction defects or atrioventricular block:

Paravalvular abscess

Diagnostic Criteria for Infective Endocarditis (Duke):

Major Blood Culture Criteria

Ñ    Two positive blood cultures for typical organisms:

S viridans, Streptococcus bovis, a HACEK group organism, community-acquired S aureus and enterococci

Ñ    Three or more positive blood cultures drawn at least 1 hour apart

Major Echocardiographic Criteria

Ñ    Vegetations

Ñ    Myocardial abscess

Ñ    Dehiscence of a prosthetic valve

Ñ    New-onset valvular regurgitation

Minor Criteria

Ñ    Predisposing heart condition or intravenous drug use

Ñ    Fever of 38°C (100.4°F) or higher

Ñ    Vascular phenomenon / Immunological phenomenon

Ñ    Positive blood culture results not meeting major criteria

Ñ    Serologic evidence of active infection with an organism consistent with infective endocarditis:

Brucella, Coxiella burnetii, Legionella

Ñ    Echocardiogram results consistent but not meeting major echocardiographic criteria

Positive Diagnosis

Ñ    2 major

Or

Ñ    1 major, 3 minor

Or

Ñ    All 5 minor

Management

Cure

Drugs

Ñ    Empirical therapy:

·          Benzylpenicillin

·          Gentamicin

·          Flucloxacillin:

Acute, covers Staphylococci

Ñ    Streptococci:

Benzylpenicillin

Amoxycillin

Ñ    Staphylococci:

Flucloxacillin and gentamicin

Ñ    MRSA:

Vancomycin, gentamicin, rifampicin

Ñ    Enterococci:

Amoxycillin and gentamicin

Ñ    Coxiella:

Doxycycline, co-trimoxazole, rifampicin or ciprofloxacin

Ñ    Fungi:

·          Flucytosine and fluconazole

·          Amphotericin:

Flucytosine resistance, Aspergillus

·          Miconazole:

Decreased renal function

Surgery

Ñ    Congestive cardiac failure refractory to medical therapy

Ñ    Fungal endocarditis

Ñ    Persistent bacteraemia:

>72 hours

Ñ    Recurrent septic emboli

Ñ    Rupture of an aneurysm of the sinus of Valsalva

Ñ    Myocardial abscess

Ñ    Kissing infection of the anterior mitral leaflet in aortic valve endocarditis

Prevention

Drugs

Ñ    Prophylactic antibiotics prior to:

Dentistry

Surgical procedure

Invasive investigations

Lifestyle Adjustments

Ñ    Good oral hygiene

Prognosis

Ñ    Staphylococci 30% mortality

Ñ    Bowel organisms 14% mortality

Ñ    Streptococci 6% mortality

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