Infective endocarditis

Infective EndocarditisPRATIK KUMAR

080201186

DefinitionInfection of the endocardial surface of heart characterized by - Colonization or invasion of the heart valves (native or

prosthetic) or the mural endocardium by a microbe, - leading to formation of bulky, friable vegetation composed

of thrombotic debris and organisms- often associated with destruction of underlying cardiac

tissue.

Sites involved•Heart valves

•Ventricular septum defects

•Mural endocardium

• Intracardiac devices

• INFECTIVE ENDARTERITIS – analogus

ACUTE ENDOCARDITIS

• Destructive and tumultuous infection, frequently of a previously normal heart valve, with a highly virulent organism

• Hematogenoulsy seeds

• If untreated, leads to death within weeks

SUBACUTE ENDOCARDITIS

• Organisms of low virulence causing infection in a previously abnormal heart, particularly on deformed valves.

• Disease appear insidiously and pursue a protracted course of weeks to month

• Recover after appropriate antibiotic treatment

Classification

CARDIAC AND VASCULAR ABNORMALITIES

• RHD

• Myxomatous mitral valve

• Degenerative calcific valvular stenosis

• Bicuspid aortic valves

• Prosthetic valves

HOST FACTORS

• Neutropenia

• Immunodeficiency

• Malignancy

• Therapeutic immunosuppression

• Diabetes mellitus

• Alcohol

• IV drug abuse

Predisposing factors

Microbiology•Staphylococcus aureus (35%) : Either healthy or deformed valves, IV drug

abusers (polymicrobial), devices

•Streptococcus viridans (32%) : Native but previously damaged/abnormal valves

•Enterococci (8 %)

•CoNS - S. epidermidis (4%): Prosthetic valve endocarditis, devices

•G –ve bacilli of HACEK group (4%)

•Yeast and Fungi(1%)

•Culture negative endocarditis (5 %)

PathogenesisPortal of entry:◦ Dental / Surgical Procedures◦ Contamination by IV drug use◦ Obvious infections (RS/Skin)◦ Occult source from gut, oral cavity◦ Trivial injuries.◦ Intravascular catheter infection◦ Nosocomial wounds◦ Chronic invasive procedures

Endothelial Injury

Uninfected Platelet-Fibrin thrombus (NBTE)

Transient bacteremia and attachment at NBTE

Proliferation and pro-coagulant state

Infected, friable, bulky vegetation

Morphology• Friable, bulky vegetation containing fibrin, inflammatory cells, and microbes

• Aortic and mitral valves involved most commonly.

• Right side valve involvement in iv drug users.

Constitutional symptoms

--- Cytokine release ?

Symptoms

- Damage to intracardiac structures

- Embolization of vegetation fragments

- Hematogenous infection

- Immune complex

Clinical features

Sub-acute Endocarditis

• Persistent fever• Constitutional symptoms• New signs of valve

dysfunction• Heart failure

• Embolic Stroke• Peripheral arterial

embolism

• Other features

Definitive Endocarditis if,

- Two major or,

- One major and three minor or,

- five minor

Possible Endocarditis if,

- One major and one minor or,

- Three minor

Modified Dukes Criteria for diagnosis of Infective Endocarditis

Major CriteriaPositive blood culture ◦Typical organism from two cultures ◦Persistent positive blood cultures taken > 12 hours apart ◦Three or more positive cultures taken over more than 1 hour.

Endocardial involvement ◦Positive echocardiographic findings of vegetations ◦New valvular regurgitation

Minor Criteria

•Predisposition: Predisposing valvular or cardiac abnormality • Intravenous drug misuse •Pyrexia ≥38°C (≥100.4°F)•Embolic phenomenon •Vasculitic/ immunologic phenomenon •Blood cultures suggestive: -organism grown but not achieving

major criteria •Suggestive echocardiographic findings

INVESTIGATIONS

AVINASH BAJJURI

.

Microbiology Blood cultures:Key diagnostic investigation in infective endocarditis.Isolation of microorganism from culture is important for

diagnosis and also for treatment.At least 3 sets of samples should be taken from different

venepuncture sites over 24 hours.

Serology Can be sent when the diagnosis is suspected and the

cultures are negative.They aid in cases where the organisms will not grow in

blood cultures(Coxiella,Legionella,Bartonella)ECG

To detect complications like MI,conduction abnormalities.CHEST X RAY

.

EchocardiographyIt can identify the presence and size of

vegetations,detect intracardiac complications and assess cardiac function.

Transthoracic echocardiography is noninvasive and has high specificity for visualising vegetations.

Transoesophageal echocardiography is more sensitive than TTE.It can detect small vegetations,prosthetic endocarditis and intra cardiac complications.

.

Complete blood counts

may show anamia and increased WBC counts.Urea and Creatinine:

may be elevated due to glomerulonephritisLiver biochemistry:

Serum alkaline phosphatase may be increasedInflammatory markers

CRP,ESR are increased in infection .CRP also helps in monotoring response to therapy.

Urine

proteinuria and hematuria occur frequently.

TREATMENTAntimicrobial Therapy

Therapy requires identification of specific pathogen and its susceptibility to antimicrobials.

Empirical therapy should be started as soon as possible targeting most likely pathogens.

Bactericidal drugs should be used.

Resolution of fever occurs in 5 to 7 days.if fever persists patient should be evaluated for complications like paravalvular abscess and extracardiac abscess.

Serologic abnormalities resolve slowly and do not reflect response to treatment.

Antibotic regimen for infective endocarditis Streptococci

Benzyl penicillin (1.2g 4 hourly) 4-6 weeks

Gentamicin (1mg/kg 8-12 hourly) 4-6 weeksEnterococcio Ampicillin sensitive

Ampicillin (2 g 4 hourly) 4-6 weeks, and

Gentamicin (1mg/kg 8-12 hourly) o Ampicillin resistant

Vancomycin(1g 12hourly) 4-6 weeks, and

Gentamicin (1mg/kg 8-12 hourly)

StaphycoccioPenicillin sensitive

Benzyl penicillin I.V(1.2 g 4 hourly)oPenicillin resistant but methicillin sensitive

Flucloxacillin I.V (2g 4 hourly )oBoth penicillin and methicillin resistant

Vancomycin I.V (1g 12 hourly) and

Gentamicin

.

Surgery

Indications patients with direct extension of infection to

myocardial structuires.Prosthetic valve dysfunction.Congestive heart failure.Badly damaged valves.IE caused by fungi or gram-ve or resistant organisms.Large vegetations on echocardiographyRecurrent embolic attacks.

Prophylaxis

High risk category prosthetic cardiac valvesPrevious bacterial endocarditis,even in absense of

heart disease.Complex cyanotic congenital heart disease(TGA,TOF) Surgically constructed systemic pulmonary shunts.

Moderate risk categoryRheumatic and other valvular dysfunctionCongenital cardiac malformationsHypertrophic cardiomyopathyMitral valve prolapse with valvular regurgitation

Regimen for IE prophylaxis

Standard oral regime

Amoxicillin 2 g 1hr before procedure

Inability to take oral medication

Ampicillin 2g IV or IM 1hr before procedurePenicillin allergy

Clindamycin 600 mg

Clarithromycin 500 mg

Cephalexin 2 g.

Thank you.