Infective endocarditis

Question 1

Definition of infective endocarditis

Answer 1

• Infection of the endocardial surface of the heart
• Classification based on etiologic agen
• Pathogenesis: hematogenous spread via bacteremia, and subsequent adherence to (usually) damaged valves
• Vegetations allow bacterial growth within a protective sheath of fibrin, platelets, and RBCs

Question 2

Common infectious causes of endocarditis (GP cocci)

Answer 2

• Staph aureus: most common bacterial cause, results in rapid mortality w/o antibio Rx
• Usually more virulent, can affect normal valves and comes from hospitals or IV drugs
• Viridians strep: alpha-hemolytic, live in oral cavity
• Usually infect only damaged valves, more sub-acute Sx

Question 3

Other infectious causes of endocarditis

Answer 3

• Group D strep (S gallolyticus bovis): associated w/ colon CA, all pts should get colonoscopy
• Nutritionally deficient strep (abiotrophia, granulicatella)
• HACEK: GN coccobacilli of normal oral flora
• H= haemophilus
• A= actinobacillus
• C= Cardiobacterium
• E= Eikenella
• K= Kingella
• Culture negative: fungi, rickettsiae, chlamydia

Question 4

Prosthetic valve IE

Answer 4

-Coagulase negative staph (S epidermitidis) most common

Question 5

Physical findings in IE

Answer 5

• Fever, MSK Sx
• Changing murmur
• Peripheral stigmata: splinter hemorrhages (linear under nails), petechiae, osler nodes (tender nodules on digits), janeway lesions (painless macules on palms and soles), roth spots (retinal hemorrhage w/ clear center)

Question 6

Complications of IE

Answer 6

• CHF
• Peripheral emboli (brain, kidney)
• Glomerulonephritis
• Stroke
• (!)Mycotic aneurysm (often in brain): due to bacterial invasion, emboli, or immune complex deposition

Question 7

Criteria for Dx (duke)

Answer 7

• Major: 2 separate positive blood cultures
• Evidence of endocardial involvement (vegetations) on echo
• Need 2 major, or 1 major 3 minor or 5 minor
• Minor: IVDU, any of the peripheral stigmata, etc

Question 8

Rx of IE

Answer 8

• Bacteristatic antibios will not work, must use bactericidal
• Indications for surgery: refractory CHF, >1 serious embolic episode, uncontrolled bacteremia >7days, inter cardiac abscess, persistent fever >7 days, fungal endocarditis