Infective Endocarditis (IE) in Adults: AHA Scientific statement

Definition

Epidemiology

- incidence of 15-20 thousand new cases

- 4th leading cause of mortal infections (urospsis, pneumonia, intra-abdominal)

-

Risks: - IVDA > Staph. in. R. sided valves. No emboli from R valvular ds.

- prothetic valves > coagulase negative staphylococci

Diagnosis

Classic Oslerian Symptoms: bacteremia/fungemia, active valvulitis, perhipheral emboli, immunologic vascular phenomenon

Echocardiography: (tranthoracic) sensitivity < 60%, specificity > 98% (minimum 2mm in size)

(confounded by obesity, COPD, chest wall deformities in up to 20% of adults)

(transesophageal) sensitvity > 76%, specificity > 94%; blind spots

Blood cultures: major criteria but up to 5% are negative. 3 sets of aerobic/anaerobic. Early antibiotics. 2-4 day wait acceptable if initial cultures negative without increased morbidity.

Negative cultures: HACEK, Bartonella, nutritionally variant strep (5-7%), Brucella, Legionella, fungi (Aspergillus, Candida, Cryptococcus), coxiella, chlamydia

Classification

Duke criteria (1994)

- negative predictive value > 98%

- specificity ~ 99%

Management

Prognosis

CHF - depends on valve involved (up to 30%) aortic > mitral > tricuspid

- if they are to develop severe CHF, 66% will do so by the first year

- delaying surgery until frank ventricular decompensation doubles operative mortality( 11-33%)

Embolization - 22-50% oc cases of IE

- 65% involve CNS (middle cerbral artery >90%)

* 20-40% of patients develop neurologic sequelae

- assoc. with staph, candida, HACEK; predicted by nonhealing lesions or increasing size

- rate of embolization drops in first 2 weeks of Ab. therapy

Periannular extension - bad prognositic indicator for mortality, CHF, surgery

- often occur weakest portiion (membranous septum/ AV node) --> heart block

- fistulas, shunts; more common with IVDA/aortic valve

- only TEE is successful at picking up abscesses (88% roughly)

Splenic abscess - (rare)

- left sided IE (40%) of cases can give splenic infarction

- only 5% co on to develop abscess; splenomegaly (30%), pain

- Viridans / Staphy = 40% of cases

- evaluated with abdominal CT/ MRI

Mycotic aneurysms - (uncommon)

- infection through the vessel wall due to emboli

Anticoagulation - native-valve should not be used d/t possibility of intracerebral hemorrhage

Future

- Pending refinements in the Duke criteria: ESR/CRP, new clubbing, splenomegaly, hematuria

1. What organisms are commonly encountered?

Streptococci, enterococci, staphylococci

HACEK: Haemophilus, Actinomycetes, Cardiobacterium, Eikenella, Kingella

2a. What does the new onset of conduction system abnormalities in the setting of endocarditis imply?

- perivalvular and /or myocardial abscess

2b. What are the classic echocardio findings?

(vegetations, abscesses, prosthetic valve dehiscence, new regurgitation)

mobile, echodense masses attached to valvular leaflets/mural endocardium

periannular dehiscence

new dehiscense of a valvular prosthesis

3. What are some clinical manifestations thought to be due to deposition of immune complexes rather than invasion?

- Roth spots (retina)

- Osler nodes (tender nodules on terminal phalanx)

- Janeway lesions (painless macules on palms/soles)

- Petechiae / purpura