Exam 3: Bone and Joint Infections Flashcards
What is osteomyelitis?
Infection of the bone
-causes inflammation of the bone marrow and surrounding bone
What is septic arthritis?
Inflammatory reaction with the joint tissue and fluid due to a microorganism
What is prosthetic joint infection?
Infection of a prosthetic joint and joint fluid
What test do we use to identify bone infections?
Blood cultures
What is the most common pathogen in bone/joint infections?
Staphylococcus aureus
How is antibiotic therapy different with bone and joint infections?
Need therapy for longer durations and higher doses
-Often use IV therapy for the entire duration
What is the typical treatment duration for osteomyelitis?
4-8 weeks
What is the typical treatment duration for septic arthritis?
2-4 weeks
What is the typical treatment duration for prosthetic joint infections?
6-12 weeks
What are the 3 pathways of osteomyelitis pathogenesis?
Hematogenous Spread
-microbe reaches bone via bloodstream
Contiguous Spread
-microbe reaches bone from soft tissue infection or direct inoculation
Vascular insufficiency
-Microbe reaches bone from soft tissue infection
What is the standard of care for diagnosis of osteomyelitis?
MRI
What are the two components of osteomyelitis treatment?
Surgical Intervention
Antibiotic Therapy
When initiating antibiotic therapy for a patient with osteomyelitis, what is important to consider before initiating?
We may hold antibiotic therapy initially while awaiting biopsy/surgical intervention
-if the patient is clinically stable
-because giving abx before a biopsy reduces the likelihood of isolating a culture
What treatment options do we have for empiric antibiotic therapy for osteomyelitis?
Cefazolin
Ceftriaxone
Cefepime
Piperacillin/Tazobactam
Ampicillin/Sulbactam
Meropenem
Ciprofloxacin
Levofloxacin
+ MRSA Coverage:
Vancomycin
Daptomycin
Linezolid
If anaerobic coverage is desired in osteomyelitis treatment, what drug can we add?
Metronidazole
What is the typical duration of osteomyelitis treatment?
4-8 weeks
What is the length of treatment for vertebral osteomyelitis due to MRSA?
8 weeks
If a patient has a diabetic foot infection related to osteomyelitis and they have a complete resection of all infected bone/tissue, how long is treatment duration?
2-5 days
If a patient has a diabetic foot infection related to osteomyelitis and they have resection of all osteomyelitis but soft tissue infection still remains, how long is treatment duration?
1-2 weeks
If a patient has a diabetic foot infection related to osteomyelitis and they have a resection performed but osteomyelitis remains how long is treatment duration?
3 weeks
If a patient has a diabetic foot infection related to osteomyelitis and they do not have any resection, how long is treatment duration?
6 weeks
What are the 2 oral options for osteomyelitis?
Rifampin
Dalbavancin
When is rifampin an option for osteomyelitis treatment?
If we are treating streptococcus, MSSA, or MRSA
*not for Gram -
What is the dosing strategy for dalbavancin in osteomyelitis?
2-dose strategy
What is the half-life of dalbavancin?
346 hours
Besides staph aureus, what is another common bacteria that can cause septic arthritis?
Neisseria gonorrhoeae
What are the common signs of septic arthritis?
Joint pain, Decreased range of motion, Swelling, Erythema, Warmth, Fever, Chills
*Monoarticular in the majority of cases
What test is normally used to diagnose septic arthritis?
Arthrocentesis
-get sample of purulent, low viscosity synovial fluid
-PMN count > 50,000 is positive
What is the treatment for septic arthritis?
Same as osteomyelitis
What is the typical duration of septic arthritis treatment?
2-4 weeks
What is the treatment duration for S. aureus septic arthritis treatment?
4 weeks
What is the treatment duration for Streptococci septic arthritis treatment?
2 weeks
What is the treatment duration for N. gonorrhoeae treatment?
7-10 days
What are the symptoms of a prosthetic joint infection?
Joint pain, Decreased range of motion, Swelling, Erythema, Warmth, Fever, Chills
**Sinus tract or persistent wound drainage over joint prosthesis
**Loosening of prosthesis
**Important to review history of prosthesis
What are the 3 primary types of surgical intervention in prosthetic joint infections?
- Debridement and retention of prosthesis
- 1-stage exchange
- 2-stage exchange
What are the benefits and downsides of the debridement and retention of prosthesis surgical approach in prosthetic joint infections?
Clean things up but the prosthesis stays, you may change the liner
-benefit is that the joint does not have to be removed
-downside is we can never fully cure the patient and they may need long term or lifelong therapy
What is the 1-stage exchange surgical approach to prosthetic joint infections?
Done in one surgery, you take the infected joint out and immediately put a new one in
-downside is that the area is still infected and it will need long term therapy
What is the 2-stage exchange surgical approach to prosthetic joint infections?
You remove the joint and put a spacer in, then do 5 weeks of antibiotics
-Then you put a new joint in so that it goes into an uninfected area
-Problem is that this is uncomfortable, the spacer hurts, and patient mobility is limited
When would we use rifampin in prosthetic joint infections?
Retention of prosthesis or 1-stage exchange
