EXAM 5 Bones and Bolts Dr. Cluck

Question 1

FOCUS on the EXAM will be on Ostheomyelits

Question 2

What are the findings of the OVIVA trial?

EXAM !! 1-2 questions

Answer 2

compared IV vs partial IV vs oral antibiotics
-looking at treatment failure

Results: Non-inferiority of IV to oral
-it is fine to use oral antibiotics in Osteomyelitis

Question 3

In the trial, OVIVA IV antibiotics were compared to oral antibiotics. Why did they mostly use FQs in the oral group?

Answer 3

It has a 1:1 IV-to-oral conversion ratio, making it easy to compare IV to oral in the study

Question 4

Which characteristic is important for an oral drug to treat prosthetic joint infection?

may ask on the EXAM !!!

Answer 4

Oral Bioavailability

Question 5

What is an important counseling point for the antibiotic Rifampin?

Answer 5

orange coloring of body fluids
-urine, tears, sweat

(huge CYP inducer)

Question 6

REMINDER:
What is the drug regimen for Osteomyelitis treatment with Dalbavancin?

EXAM Q !!!

Answer 6

Day 1: 1500 mg
Day 8: 1500 mg

Question 7

Why might we need multiple doses of Dalbavancin in Osteomyelitis?

Pathophysiology of Osteomyelitis

Answer 7

after the infection, there is a build-up of pus (sequestrum) and abscess, which makes it difficult for the drug to get there

Question 8

What are the two Osteomyelitis Classification Schemes?

Answer 8

-Cierny and Mader classification
looks at the portion of the affected bone

-Lew and Waldvogel classification
tells if it is acute or chronic osteomyelitis

(not used in practice, he doesn’t care about it, probably not on the EXAM)

Question 9

How is Contagious Osteomyelitis different from Hematogenous Osteomyelitis?

Answer 9

Contagious:
-develops from an injury -> Osteomyelitis is then secondary to the injury (bump the toe)
-polymicrobial

Hematogenous:
-spreads from the blood, monomicrobial

Question 10

In which patients do we usually see Contagious Vs. Hematogenous Osteomyelitis?

NOT ON EXAM

Answer 10

Contagious:
-frequently in elderly (sometimes in children)
-often diabetic patients (ingrown toenail, cellulitis, minor trauma -> infection)

Hematogenous: in prepubertal children

Question 11

Which organisms are possibly causing Contagious Osteomyelitis?

Answer 11

Polymicrobial
-Staphylococci
-Streptococci
-Gram-negative
-anaerobes

-> need broad antimicrobial coverage

Question 12

Which organisms most commonly cause Hematogenous Osteomyelitis?

Answer 12

-Staphylococci is most common

-Streptococci
-Cutibacterium
-E. coli
-Pseudomonas (IV drug use)
-Mycobacteria
-Candida

Question 13

Why do patients with sickle cell disease have an increased risk of Osteomyelitis?

Answer 13

These patients often don’t have a spleen
->higher risk for infections of encapsulated organisms like Salmonella

Question 14

How is Osteomyelitis diagnosed?

Answer 14

Bone biopsy is the gold standard

-CT or MI are most commonly done
-X-ray: shows bone loss

Question 15

Which labs should be monitored for Osteomyelitis?

Answer 15

-Erythrocyte sedimentation rate (ESR)
-C-reactive protein
not WBC

get a baseline and observe if the levels change during the infection

Question 16

What is the treatment approach for Osteomyelitis?

Answer 16

Antibiotics
-to completely get rid of the bacteria patients often need an amputation

Question 17

What is the duration of therapy for Osteomyelitis?

Answer 17

4-6 weeks (could be longer depending on the organism)

-allows for revascularization

Question 18

What would be an empiric treatment for Osteomyelitis?

Answer 18

Daptomycin

Vancomycin is often seen, but treatment requires 4-6 weeks, it is not recommended for long-term use
-> Nephrotxic

Question 19

Which drugs have good bone penetration?

Answer 19

Clindamycin - not the best choice
Trimethrophan
Linezolid - not the best choice
Rifampin - NOT for monotherapy !!
FQ - causes C- diff with long-term use
ß-Lactam -might work fine

Penetration is not as important as it was tought

Question 20

Why might Linezolid despite having great bone penetration, not be the best choice for Osteomyelitis?

Answer 20

bone marrow impression after 14 days
neuropathy after 28 days (not reversible)
optic neuritis

Question 21

After complete resection (amputation)of the infected bone, how long should antibiotics be continued?

Answer 21

if the source of infection is still there -> still need long treatment

-if the source was amputated -> a few days of treatment is fine

Question 22

Which lab values should be monitored when using Linezolid?

Answer 22

-CBC to see if they have thrombocytopenia
STOP linezolid if they have thrombocytopenia

Question 23

Which antibiotic is the DOC for Osteomyelitis?

Answer 23

Dalbavancin or Oritavancin
need at least 2 doses !!!

-only covers gram (+)
Don’t use it if the organism is gram-negative !!

Question 24

Which organism is associated with Prosthetic Joint infections?

Answer 24

-Coagulase Negative Staph !! (like Staphylococcus epidermidis)
-Staph aureus !!

-Gram-negative (rare)
-Anaerobes

common contaminants become pathogenic (C. acnes) !!!

Question 25

Treatment approach for PIJ

Answer 25

-ideally the infected joint should be removed -> then antibiotic therapy for 2-6 weeks -> joint replacement

-if cant be removed:
Debridement, washout around the prosthesis
Suppressive

Question 25

Other treatment options for PJI

Answer 25

-Antibiotic-impregnated beads

-Antibiotic-impregnated segments (often Aminoglycoside)

Question 26

Characteristics of Septic Arthritis

Answer 26

-secondary to hematogenous spread or direct inoculation

-Synovial membrane is highly vascularized
and lacks a basement membrane

Question 27

What causes the most damage in Septic Arthritis?

Answer 27

-bacteria, inflammation, and tissue ischemia with resultant necrosis

-most of the damage is caused by host inflammation process

Question 28

Clinical Presentation Septic Arthritis

Answer 28

-often with 1-2 week history of swelling and pain in joint

-fever is not always present
-WBC, ESR, and CRP will likely be elevated

Question 29

Which organism causes Septic Arthritis?

Answer 29

Staph aures -> KNOW how to treat MRSA, MSSA
-ß-strep (Grup A and B Strep)
-Gram-negative rods
-Gonococcus

Question 30

How is Septic Arthritis treated?

Answer 30

-need drainage and antibiotics
-usually 2-4 weeks
-MRSA and GRN need 4 weeks