Cardiovascular infection

Question 1

Define infective endocarditis

Answer 1

Infection of some part of the endocardium, usually valves. Can also be septal defects.

Question 2

What is the usual etiology of fulminant IE and chronic/subacute IE?

Answer 2

fulminant: S. aureus, S. pyogenes
subacute: Strep virridans

Question 3

What are predisposing factors for IE?

Answer 3

• structural heart disease
• prosthetic valves
• IVDU
• prior history
• health-care associated

Question 4

What is the pathogenesis of IE?

Answer 4

Basic: need 1) endothelium damage +thrombosis, 2) bactermia

Question 5

What are the symptoms of IE?

Answer 5

Fever (80%)

Chills

Weakness

Dyspnea

Sweats

***The symptoms go on, but they are all non-specific. You have to think of IE in order to make the diagnosis**

Question 6

What are signs of IE?

Answer 6

• Fever
• Murmur
• signs of emboli
• skin manifestations
  
  • splinter hemorrhages
  • petechiae
  • Osler’s nodes (painful)
  • Janeway lesion (not painful)
• Roth spots (hemorrhage in the eye)

Question 7

What is the diagnostic approach to IE?

Answer 7

Blood culture is most important!!! (90% of IE will have positive culture, but some hard-to-culture organisms will give a negative result)

Other findings present in some, but not all: anemia, thrombocytopenia, hematuria, proteinuria

CXR

Echo (transesophageal more sensitive than transthoracic)

Question 8

What is the most likely etiology of IE in native valve, IVDU and prosthetic valve IE? What is the empric treatment for each?

Answer 8

Native valve:

• S. aureus or Strep virridans
• Treat with vancomycin and ceftriaxone

IVDU

• S. aureus, including MRSA
• vancomycin + gentamicin

Prosthetic valve:

• Staph
• vancomycin +gentamicin +rifmapin

**always consult infectious diseases***

Question 9

Roughly how many prosthetic joint get infected after surgery?

Answer 9

about 1%

Question 10

What are risk factors for post-arthroplasty joint infection?

Answer 10

• previous infection at the same site*
• smoking*
• obesity
• rheumatoid arthritis
• immune suppression
• post-op wound healing complications **

others

Question 11

What is the most common etiology of prosthetic joint infection?

Answer 11

Staphylococcus (esp. S, aureus and CNS)

Question 12

What is the pathogenesis of prosthetic joint infection? Where does the organism come from? How does it evade the immune system?

Answer 12

• small infectious dose required
• usually skin flora, but can be hemtogenous spread too.
• forms a biofilm that protects it from the host immune system and antibiotics

Question 13

What is the common presentation of acute and “chronic” prosthetic joint infection?

Answer 13

Acute: increase in pain so it’s severe and not just when bearing weight, swelling, erythema, warmth, fever

Chronic: pain alone, loosening of the bone/cement interface, sinus tracts

Question 14

What is the diagnostic approach to prosthetic joint infection?

Answer 14

Clinical

• there are criteria that include isolating the organism from aspirate on 2 occasions or the presence of a sinus tract, or a collection of other signs

Imaging

• not terribly helpful. the best is ultrasound.

Question 15

What is the treatment for prosthetic joint infection?

Answer 15

Take it out. (and treat with appropriate antibiotics)