EXAM 5 Bones and Bolts Dr. Cluck Flashcards
FOCUS on the EXAM will be on Ostheomyelits
What are the findings of the OVIVA trial?
EXAM !! 1-2 questions
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
In the trial, OVIVA IV antibiotics were compared to oral antibiotics. Why did they mostly use FQs in the oral group?
It has a 1:1 IV-to-oral conversion ratio, making it easy to compare IV to oral in the study
Which characteristic is important for an oral drug to treat prosthetic joint infection?
may ask on the EXAM !!!
Oral Bioavailability
What is an important counseling point for the antibiotic Rifampin?
orange coloring of body fluids
-urine, tears, sweat
(huge CYP inducer)
REMINDER:
What is the drug regimen for Osteomyelitis treatment with Dalbavancin?
EXAM Q !!!
Day 1: 1500 mg
Day 8: 1500 mg
Why might we need multiple doses of Dalbavancin in Osteomyelitis?
Pathophysiology of Osteomyelitis
after the infection, there is a build-up of pus (sequestrum) and abscess, which makes it difficult for the drug to get there
What are the two Osteomyelitis Classification Schemes?
-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)
How is Contagious Osteomyelitis different from Hematogenous Osteomyelitis?
Contagious:
-develops from an injury -> Osteomyelitis is then secondary to the injury (bump the toe)
-polymicrobial
Hematogenous:
-spreads from the blood, monomicrobial
In which patients do we usually see Contagious Vs. Hematogenous Osteomyelitis?
NOT ON EXAM
Contagious:
-frequently in elderly (sometimes in children)
-often diabetic patients (ingrown toenail, cellulitis, minor trauma -> infection)
Hematogenous: in prepubertal children
Which organisms are possibly causing Contagious Osteomyelitis?
Polymicrobial
-Staphylococci
-Streptococci
-Gram-negative
-anaerobes
-> need broad antimicrobial coverage
Which organisms most commonly cause Hematogenous Osteomyelitis?
-Staphylococci is most common
-Streptococci
-Cutibacterium
-E. coli
-Pseudomonas (IV drug use)
-Mycobacteria
-Candida
Why do patients with sickle cell disease have an increased risk of Osteomyelitis?
These patients often don’t have a spleen
->higher risk for infections of encapsulated organisms like Salmonella
How is Osteomyelitis diagnosed?
Bone biopsy is the gold standard
-CT or MI are most commonly done
-X-ray: shows bone loss
Which labs should be monitored for Osteomyelitis?
-Erythrocyte sedimentation rate (ESR)
-C-reactive protein
not WBC
get a baseline and observe if the levels change during the infection
What is the treatment approach for Osteomyelitis?
Antibiotics
-to completely get rid of the bacteria patients often need an amputation
What is the duration of therapy for Osteomyelitis?
4-6 weeks (could be longer depending on the organism)
-allows for revascularization
What would be an empiric treatment for Osteomyelitis?
Daptomycin
Vancomycin is often seen, but treatment requires 4-6 weeks, it is not recommended for long-term use
-> Nephrotxic
Which drugs have good bone penetration?
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
Why might Linezolid despite having great bone penetration, not be the best choice for Osteomyelitis?
bone marrow impression after 14 days
neuropathy after 28 days (not reversible)
optic neuritis
After complete resection (amputation)of the infected bone, how long should antibiotics be continued?
if the source of infection is still there -> still need long treatment
-if the source was amputated -> a few days of treatment is fine
Which lab values should be monitored when using Linezolid?
-CBC to see if they have thrombocytopenia
STOP linezolid if they have thrombocytopenia
Which antibiotic is the DOC for Osteomyelitis?
Dalbavancin or Oritavancin
need at least 2 doses !!!
-only covers gram (+)
Don’t use it if the organism is gram-negative !!
Which organism is associated with Prosthetic Joint infections?
-Coagulase Negative Staph !! (like Staphylococcus epidermidis)
-Staph aureus !!
-Gram-negative (rare)
-Anaerobes
common contaminants become pathogenic (C. acnes) !!!
Treatment approach for PIJ
-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
Other treatment options for PJI
-Antibiotic-impregnated beads
-Antibiotic-impregnated segments (often Aminoglycoside)
Characteristics of Septic Arthritis
-secondary to hematogenous spread or direct inoculation
-Synovial membrane is highly vascularized
and lacks a basement membrane
What causes the most damage in Septic Arthritis?
-bacteria, inflammation, and tissue ischemia with resultant necrosis
-most of the damage is caused by host inflammation process
Clinical Presentation Septic Arthritis
-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
Which organism causes Septic Arthritis?
Staph aures -> KNOW how to treat MRSA, MSSA
-ß-strep (Grup A and B Strep)
-Gram-negative rods
-Gonococcus
How is Septic Arthritis treated?
-need drainage and antibiotics
-usually 2-4 weeks
-MRSA and GRN need 4 weeks
