Bone & Joint Infections Flashcards
What are the three main types of bone and joint infections?
- osteomyelitis - infection of the bone causing inflammation of the bone marrow and surrounding bone
- septic arthritis - inflammatory reaction within the joint tissue and fluid due to a microorganism
- prosthetic join infection - infection of a prosthetic join and joint fluid
What is the pathogenesis of the bone and joint infections?
- Hematogenous spread - microbe reaches bone via bloodstream
- Contiguous spread - microbe reaches bone from soft tissues infection or direct inoculation
- Vascular insufficiency - microbe reaches bone from soft tissue infection
- direct inoculation = puncture wound, trauma, surgery
What is the most common organism associated with bone and joint infections?
staphylococcus aureus
How does osteomyelitis present?
- fever
- pain
- swelling
- decreased ROM
How is osteomyelitis diagnosed?
- MRI is standard of care
- Bone aspiration, biopsy, and/or surgical debridement for cultures and pathology
X-rays and labs such as elevated WBCs can also be used
What are the pillars of treatment for osteomyelitis?
surgical intervention + antibiotic therapy
Which antibiotics can be used for empiric therapy for the bone and joint infections?
- cefazolin, ceftriaxone, cefepime
- pip/tazo, ampicillin/sulbactam
- meropenem
- ciprofloxacin, levofloxacin
+
- vancomycin
- daptomycin
- linezolid
Pick an agent from the top and an agent from the bottom.
MSSA/Strep coverage + MRSA coverage
Which agent should be added if anaerobic coverage is desired?
metronidazole
Likely desired in DM patients
What are the pathogen-directed treatment options for MSSA?
- Nafcillin
- cefazolin
What are the pathogen-directed treatment options for MRSA?
- vancomycin
- linezolid
- dalbavancin
- daptomycin
- TMP/SMX
What is the abx treatment duration for a patient with vertebral osteomyelitis due to MRSA?
8 weeks
What is the abx treatment duration for a patient with DFI related osteomyelitis that had a complete resection of all infected bone and tissue?
whole limb amputation
2-5 days
What is the abx treatment duration for a patient with DFI related osteomyelitis that had a complete resection of all osteomyelitis, but there is still soft tissue infection remaining?
Toe is amputated, but there is still infection in the surrounding skin.
1-2 weeks
What is the abx treatment duration for a patient with DFI related osteomyelitis that underwent resection, but there is still osteomyelitis?
Toe has been amputated, but the margin still has osteomyelitis
3 weeks
What is the abx treatment duration for a patient with DFI related osteomyelitis that did not undergo any resection?
6 weeks
What route of abx should be used for bone and joint infections?
IV or highly bioavailable oral
What are the highly bioavailable oral abx that cover streptococci?
- amoxicillin
- cephalexin
- clindamycin (if susceptible)
What are the highly bioavailable oral abx that cover MSSA?
- dicloxacillin
- cephalexin
- cefadroxil
- TMP/SMX
- linezolid
What are the highly bioavailable oral abx that cover MRSA?
- linezolid
- TMP/SMX
- clindamycin (if susceptible)
What are the highly bioavailable oral abx that cover GNRs?
- TMP/SMX
- fluoroquinolones
What are the most common pathogens for septic arthritis?
- staph aureus
- neisseria gonorrhoeae
How does septic arthritis present?
- fever
- join pain
- decreased ROM
- swelling
- typically monoarticular
How is septic arthritis diagnoses?
- Arthrocentesis –> purulent, low viscosity synovial fluid
- PMN count > 50,000
Labs and X-rays may also be used
What is the abx treatment duration for a patient with septic arthritis due to s. aureus or gram negative rods?
4 weeks
What is the abx treatment duration for a patient with septic arthritis due to streptococci?
2 weeks
What is the abx treatment duration for a patient with septic arthritis due to N. gonorrhoeae?
7-10 days
When should rifampin be used?
Rifampin should be added onto oral abx therapies that are targeting gram positive bacteria to help prevent biofilm formation in osteomyelitis and prosthetic join infections.
What is the most common causative pathogen for prosthetic join infections?
staph aureus
How do prosthetic join infections present?
- joint pain
- fever
- decreased ROM
- wound drainage over joint prosthesis
- loosening of prosthesis
How is a prosthetic join infection diagnosed?
- arthrocentesis
labs and X-ray may also be used
What are the pillars of treatment for prosthetic join infection?
surgical intervention + antibiotic therapy
What are the types of surgical intervention for prosthetic joint infection?
- debridement and retention of prosthesis
- 1-stage exchange
- 2-stage exchange
- 1SE –> take out infected joint and immediately replace –> puts a new joint in an infected area
- 2SE –> take out infected joint, add a spacer –> 6 weeks of abx –> put in new joint (two surgeries)
When is rifampin added for prosthetic joint infections?
- retention of prosthesis
- 1-stage exchange
only for staph aureus
What is the duration of abx therapy following debridement and retention of prosthesis for prosthetic join infection?
3-6 months
What is the duration of abx therapy following a 1-stage exchange for a prosthetic joint infection?
3 months
What is the duration of abx therapy following a 2-stage exchange for a prosthetic joint infection?
4-6 weeks
What is the duration of abx therapy following an amputation for prosthetic joint infection?
24-48 hours
rare
What are the benefits and drawbacks of IV vancomycin therapy?
Benefits: home infusion
Drawbacks: multiple daily doses, requires central line
What are the benefits and drawbacks of IV daptomycin therapy?
Benefits: once daily dosing
Drawbacks: go to infusion center, requires central line
What are the benefits and drawbacks to IV dalbavancin therapy?
Benefits: only requires two doses for 6 weeks of coverage, does NOT require a central line
Drawbacks: go to infusion center, bad reaction could last for 6 weeks if you had one
What are the benefits and drawbacks to PO linezolid therapy?
Benefits: by mouth, less costly
Drawbacks: requires weekly WBC monitoring, not considered a standard of care
