Infective Endocarditis

Question 1

IE Incidence

Answer 1

• Infective endocarditis
• Uncommon
• Increased incidence in elderly, IDU, and prosthetic heart valves

Question 2

Risk Factors

Answer 2

• Congenital heart disease + cyanosis
• Rheumatic heart disease following rheumatic fever
• Mitral valve prolapse with regurgitation
• Degenerative valvular lesions; stenosis, regurgitation
• Prosthetic valves
• IDU

Question 3

IE Pathogenesis

Answer 3

1. Endothelial surface of heart damaged
2. Platelet and fibrin deposition leading to nonbacterial thrombotic endocarditis formation
3. Bacteremia results in colonization of endocardial surface
4. Gram “+” more likely to adhere to NBTE from adhesion factors
5. After colonization, fibrin, platelets, and bacteria continue to aggregate and a “vegetation” forms

Question 4

Heart Valves Involved

Answer 4

1. Mitral (86%) - most commonly caused by S. viridans when rheumatic heart disease is abnormality
2. Aortic (55%) - more acute infections
3. Tricuspid (20%) - common site of staph endocarditis in IDU
4. Pulmonic (1%)

Question 5

Acute v.s. Subacute

Answer 5

• Subacute: indolent infections with less invasive organisms (Viridans), common with prior valvular heart disease
• Acute: fulminant infection following infection of a previously normal valve

Question 6

Non-virulent Organisms

Answer 6

• Low grade fever
• Malaise
• Fatigue
• Weight loss

Question 7

Virulent Organisms

Answer 7

• High grade fever (common)
• Chills, sweat
• Septic picture
• Embolization complications

Question 8

IE Clinical Features

Answer 8

• Heart murmur - common and on a scale of 1-6
• Skin lesions
• Other: renal failure, splenomegaly, back pain, abdominal pain, chest pain, etc.

Question 9

Peripheral Manifestations

Answer 9

• Osler nodes: purple/red subcutaneous papules/nodules that appear on toes and fingers and can be painful and tender
• Roth spots retinal hemorrhages usually caused by immune complex mediated vasculitis
• Janeway lesions: hemorrhagic, painless plaque that develop on palms and soles
• Splinter hemorrhages: thin, linear under nailbeds
• Petechiae: small, erythematous hemorrhagic lesions that aren’t painful or tender
• Finger Clubbing: proliferative change in the soft tissue at the ends of fingers

Question 10

Labs + Significant Tests

Answer 10

• Blood cultures
• Hematologic: WBC, BUN/SCr
• ESR
• Echocardiogram: TEE more sensitive for detecting vegetation

Question 11

IE + Major Criteria

Answer 11

• Blood: two blood cultures positive for typical IE organism
• Echo: Positive for IE, myocardial abscess, development of partial dehiscence of a prosthetic valve, new-onset valvular regurgitation

Question 12

IE + Minor Criteria

Answer 12

• Predisposing heart condition or IDU
• Fever > 38C
• Vascular phenomenon
• Immunological phenomenon
• Positive blood culture results not meeting major criteria
• Echo results consistent with IE but no other major criteria

Question 13

Vascular phenomenon

Answer 13

• Major arterial emboli
• Septic pulmonary infarcts
• Intracranial hemorrhage
• Conjunctival hemorrhage
• Janeway lesions

Question 14

Immunological Phenomenon

Answer 14

• Glomerulonephritis
• Osler nodes
• Roth spots
• Rheumatoid factor

Question 15

Diagnosis

Answer 15

• Definite Endocarditis: microorganism by vegetation culture or cardiac abscess confirmed OR meeting 2 major criteria, 1 major and 3 minor criteria, or 5 minor criteria
• Possible Endocarditis: Findings consistent with IE but falls short of definite
• Rejected: Firm alternative diagnosis or resolution of symptoms in less than 4 days or no pathological evidence at surgery or autopsy

Question 16

Treatment Guidelines

Answer 16

• Firm diagnosis: presumptive therapy
• Identify organisms: repeat blood cultures
• Bactericidal antibiotics
• Combo therapy needed often
• Duration: 4-6 weeks
• Surgical intervention may be required

Question 17

Empiric Treatment + Native Valve

Answer 17

• Vanco + Zosyn

* *Empiric = Highly dependent on potential cause of endocarditis**

Question 18

Empiric + Prosthetic Valve

Answer 18

-Vanco + Gentamicin + Rifampin

Question 19

Treatment: V. streptococci/S. Bovis + PCN Susceptible

Answer 19

• **PCN G x 4 weeks
• Ceftriaxone x 4 weeks
• PCN G x 2 weeks (when?)
• Ceftriaxone + Gent x 2 weeks

Question 20

Treatment: V. streptococci/S. Bovis + PCN Intermediate

Answer 20

• (0.12 < MIC < 0.5)
• PCN + Gent x 2 weeks
• Ceftriaxone + Gent x 2 weeks

Question 21

Treatment: V. streptococci/S. Bovis + PCN Allergy

Answer 21

• Ceftriaxone x 4 weeks

- Vanco x 4 weeks

Question 22

Treatment: Enertococci or PCN-R V. Strept. + First Line

Answer 22

• PCN G + Gent x 4-6 weeks for Strep
• Amp + Gent x 4-6 weeks - Enterococci
• Amp + Ceftriaxone

Question 23

Treatment: Enertococci or PCN-R V. Strept. + PCN-R enterococci or PCN allergy

Answer 23

Vanco + Gent x 6 weeks

Question 24

Treatment: Enertococci or PCN-R V. Strept. + High-level AMG Resistance

Answer 24

-Amp + Ceftriaxone x 6 weeks

Question 25

Treatment: Staphylococci + Native Valve

Answer 25

Methicillin-susceptible - **Nafcillin x 6 weeks - Cefazolin x 6 weeks - Vanco x 6 weeks (preferred with allergies) Methicillin-resistant/PCN Allergy - **Vanco x 6 weeks - Daptomycin x 6 weeks

Question 26

Treatment: Staphylococci + Prosthetic Valve

Answer 26

Methicillin-susceptible - Naficillin AND - Rifampin x 6 weeks AND - Gent x 2 weeks Methicillin-resistant - Vanco AND - Rifampin x 6 weeks AND - Gent x 2 weeks

Question 27

IE Prophylaxis

Answer 27

- 15-25% from invasive procedures that produce bacteremia - 10% of IE can be prevented with preprocedure antibiotics - Consider prophylaxis in those with high-risk conditions and procedures

Question 28

High-risk Conditions

Answer 28

- Presence of prosthetic heart valve - History of endocarditis - Cardiac transplant recipients who develop cardiac valvulopathy - Congenital heart disease with a high-pressure gradient lesion

Question 29

High-risk Procedures

Answer 29

- Any procedure manipulating gingival tissue or periapical region of teeth or perforation of the oral mucosa - Any procedure involving incision in respiratory mucosa - Procedures of infected skin or musculoskeletal tissue including incision and drainage of an abscess - Prophylaxis: no longer routinely recommended for GI and GU procedures