INFECTIVE ENDOCARDITISand valvular vegetations

Alex Yartsev 30/03/2010

Pathological definitions

INFECTIVE ENDOCARDITIS• The colonization or invasion of heart valves or

the mural endocardium by a microbeVEGETATIONS• Masses of thrombotic debris and organisms,

attached to valves or myocardial tissue, and destructive to that tissue

Robbins and Cotran Pathologic Basis Of Disease (8th ed)

A vegetation

Robbins and Cotran Pathologic Basis Of Disease (8th ed)

Subacute Mitral Endocarditis, Strep viridans

Acute endocarditis of congenitally bicuspid aortic

valve, by Staph aureus

Acute IE or Subacute IE?• Definition dependent on virulence and courseACUTE: 10-20% of cases• Infection of a normal valve• Rapidly progressing, usually Staph Aureus • Rapidly destructive, necrotising, ulcerative

SUBACUTE – 80-90% of cases• Infection of a previously diseased, deformed valve• Slowly progressing, usually Streptococcus • Gradually destructive, more like erosive

Robbins and Cotran Pathologic Basis Of Disease (8th ed)

There are 3 main pathogens

Defective valves: – 60% of cases its Streptococcus viridans

Normal valves– Staph Aureus especially if the valve belongs to an IV drug user

Prosthetic valves:- Staph epidermitis

OTHER ORGANISMS: Enterococci, Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella… All oral organisms

In 10-15% of cases, no organism is found.Robbins and Cotran Pathologic Basis Of Disease (8th ed)

A Word About Streptococci

• Alpha hemolytic: reduce iron from hemoglobin– Strep pneumoniae, Strep viridans

• Beta hemolytic: lysis of whole RBCs

– Group A: S.pyogenes rheumatic fever

– Group B: S.agalactiae neonatal meningitis

– Group C: S.equi “distemper of horses”

– Group D: Enterococci– Group G: S.canis dog saliva

FOREMOST:Anything that predisposes to bacteraemiaDental procedures, oral infections,IV drug use,

surgery, IV cannulas, central lines, huge obvious infections elsewhere, or minute

trivial areas of slightly broken skin

Predisposing factors

Predisposing factors

• Rheumatic heart disease• Mitral valve prolapse• Degenerative calcific valvular stenosis• NORMAL bicuspid aortic valve• Prosthetic valves• Unrepaired and repaired congenital defects

Robbins and Cotran Pathologic Basis Of Disease (8th ed)

Complications

• Brain abscess• Lung abscess• Heart failure• Glomerulonephritis (immune complexes)• Emboli anywhere

Common clinical Features

• Fever, chills, rigors• New heart murmr• New onset of heart failure signs/symptoms

Problems otherwise unexplained:• Brain abscesses• Lung abscesses• Glomerulonephritis

Uncommon clinical features• Roth spots (Retinal hemorrhages)

• Janeway lesions(painless microabscesses )

Oslers nodes(painful immune complex deposits)

Robbins and Cotran Pathologic Basis Of Disease (8th ed)Tally and O’Connor

Populations at risk

• IV drug users: usually tricuspid valve• Valve replacement patients• Patients with repaired or unmanaged septal

defects• Past history of rheumatic heart disease

Preventative measures

• COCHRANE:“There remains no evidence about whether

penicillin prophylaxis is effective or ineffective against bacterial endocarditis in people at risk who are about to undergo an invasive dental procedure. “

Diagnosis• Duke criteria: MAJOR citeria– Streptocucus viridans in blood culture– Staph aureus in blood culture in absence of

primary focus– Persistently positive blood culture: organism

consistent with infective endocarditis from• Blood cultures drawn more than 12 hours apart, or• all of three, or majority of four or more separate blood

cultures, with the first and last drawnat least 1 hour apart

– Evidence of Endocardial involvement: +ve ECHO

Diagnosis: Duke Criteria

• MAJOR CITERIA– Positive blood culture, for a characteristic organism– Echo identification of a valvular mass or partial separation

of an artificial valve

Need 2 major Or 1 major and 3 minorOr 5 minor criteria

Diagnosis: Duke Criteria

• MINOR CITERIA– Predisposing heart lesion– IV drug use– Vascular lesions eg. splintr hemorrhages or petechiae– Immunological phenomena eg. Oslers nodes, Roth spots – Single culture positive for an unusual organism– Echo findings consistent with but not diagnostic of

endocarditis

TTE or TOE?

• TTE for aortic valve• TOE for mitral, pulmonary, tricuspid• TTE less sensitive for vegetations than TOE

Practical Management

• Delay of diagnosis = lower survival• Three sets of cultures before antibiotics;• Then, commence empiric therapy• Continue for 6 weeks

Ohs Intensive Care Manual 6th ed; Therapeutic Guidelines

Empirical antibiotics• Therapeutic Guidelines suggest:– Benzylpenicillin 1.8 g q4h, PLUS– Flucloxacillin 2g q4h PLUS– Gentamicin 6mg/kg dailyALSO– Add Vancomycin if the pt has a prosthetic valve or the

infection is hosptial-acquired

Good Evidence

• COCHRANE:“There remains no evidence about whether

penicillin prophylaxis is effective or ineffective against bacterial endocarditis in people at risk who are about to undergo an invasive dental procedure. “

Most people still use ampicillin or clindamycin

Antibiotics for the prophylaxis of bacterial endocarditis in dentistry: Oliver et al, 2008