Management of Bone and Joint Infections

Question 1

What are the three main types of bone and joint infections?

Answer 1

Osteomyelitis, septic arthritis, prosthetic joint infection (PJI).

Question 2

What are the pathogenesis routes for bone and joint infections?

Answer 2

Hematogenous spread, contiguous spread, and vascular insufficiency.

Question 3

What is the most common organism in bone and joint infections?

Answer 3

Staphylococcus aureus due to its virulence, biofilm formation, and ability to colonize skin.

Question 4

What are the two pillars of treatment for osteomyelitis and PJI?

Answer 4

Surgical intervention and antibiotic therapy.

Question 5

How is osteomyelitis diagnosed?

Answer 5

MRI/CT scan, elevated ESR/CRP/WBC, and bone biopsy for culture.

Question 6

How is septic arthritis diagnosed?

Answer 6

Arthrocentesis (PMN >50,000), synovial fluid culture, imaging, and lab markers.

Question 7

How is PJI diagnosed?

Answer 7

Joint aspiration, imaging, and assessment for sinus tract or prosthesis loosening.

Question 8

What is the typical antibiotic duration for osteomyelitis?

Answer 8

4–8 weeks; longer in vertebral osteomyelitis and non-resected diabetic foot infections.

Question 9

What is the typical antibiotic duration for septic arthritis?

Answer 9

2–4 weeks: 4 weeks for S. aureus or GNRs, 2 weeks for streptococci, 7–10 days for N. gonorrhoeae.

Question 10

What is the antibiotic duration for PJI?

Answer 10

2–6 weeks IV + 3–6 months oral for retention strategies; 4–6 weeks for 2-stage exchange.

Question 11

Which oral antibiotics are considered highly bioavailable for bone/joint infections?

Answer 11

Linezolid, fluoroquinolones, TMP-SMX, doxycycline, clindamycin, rifampin.

Question 12

What novel option can be used for long-term MRSA bone infections?

Answer 12

Dalbavancin (1500 mg IV on days 1 and 8 for 6–8 weeks of coverage).

Question 13

When should empiric antibiotics be held in osteomyelitis?

Answer 13

If the patient is stable and a biopsy is pending to increase likelihood of identifying the organism.

Question 14

What is the role of rifampin in PJI treatment?

Answer 14

Used with pathogen-directed therapy in prosthesis retention or 1-stage exchange due to biofilm activity.

Question 15

What is empiric antibiotic therapy for osteomyelitis or septic arthritis in adults?

Answer 15

Vancomycin + ceftriaxone or cefepime (or nafcillin if MSSA confirmed).

Question 16

What is empiric therapy for diabetic foot osteomyelitis?

Answer 16

Vancomycin + piperacillin-tazobactam (for MRSA and anaerobic/Gram-negative coverage).

Question 17

What empiric therapy is used in children for osteomyelitis?

Answer 17

Vancomycin + cefotaxime or ceftriaxone, adjusted based on age and vaccination status.

Question 18

What is the treatment for MSSA bone or joint infection?

Answer 18

Nafcillin, oxacillin, or cefazolin IV; consider oral cephalexin, dicloxacillin, or clindamycin for step-down.

Question 19

What is the treatment for MRSA bone or joint infection?

Answer 19

Vancomycin, daptomycin, or linezolid. Dalbavancin or oritavancin may be used for long-term therapy.

Question 20

What is the treatment for Streptococcus species in osteomyelitis or arthritis?

Answer 20

Penicillin G or ceftriaxone. Clindamycin or vancomycin for beta-lactam allergy.

Question 21

What is the treatment for Enterobacterales (e.g., E. coli, Klebsiella) in bone infections?

Answer 21

Ceftriaxone, cefepime, or ertapenem (for ESBL). Fluoroquinolones if susceptible and step-down appropriate.

Question 22

What is the treatment for Pseudomonas aeruginosa in osteomyelitis?

Answer 22

Cefepime, ceftazidime, meropenem, or piperacillin-tazobactam. Consider oral ciprofloxacin if susceptible.

Question 23

What is the treatment for Neisseria gonorrhoeae in septic arthritis?

Answer 23

Ceftriaxone IV 1 g daily for 7–10 days. May transition to oral therapy if symptoms improve.

Question 24

When is rifampin added in prosthetic joint infection (PJI)?

Answer 24

For staphylococcal infections with prosthesis retention; used in combination with another antibiotic (e.g., fluoroquinolone or beta-lactam).

Question 25

What are the three routes of infection for osteomyelitis?

Answer 25

Hematogenous spread, contiguous spread, and direct inoculation (e.g., trauma, surgery).

Question 26

What diagnostic imaging is preferred for osteomyelitis?

Answer 26

MRI is preferred due to sensitivity; bone scan or CT can be used if MRI contraindicated.

Question 27

What lab findings support the diagnosis of osteomyelitis?

Answer 27

Elevated ESR, CRP, and WBC; positive blood cultures or bone biopsy.

Question 28

What is the typical antibiotic duration for hematogenous osteomyelitis?

Answer 28

Usually 4–6 weeks of IV or highly bioavailable oral antibiotics.

Question 29

What factors favor oral antibiotic therapy for osteomyelitis?

Answer 29

Pathogen identified, clinical improvement, ability to absorb PO meds, and good adherence.

Question 30

What oral antibiotics have high bioavailability suitable for bone infections?

Answer 30

Linezolid, fluoroquinolones, TMP-SMX, doxycycline, clindamycin.

Question 31

What are risk factors for MRSA in bone or joint infections?

Answer 31

Prior MRSA infection or colonization, recent hospitalization, or IV drug use.

Question 32

What is the treatment duration for septic arthritis caused by S. aureus?

Answer 32

4 weeks.

Question 33

What is the treatment duration for septic arthritis caused by Streptococcus spp.?

Answer 33

2 weeks.

Question 34

What is the treatment duration for septic arthritis caused by Neisseria gonorrhoeae?

Answer 34

7–10 days.

Question 35

What is the role of rifampin in staphylococcal PJI?

Answer 35

Used in combination for biofilm-active therapy when prosthesis is retained or exchanged in one stage.

Question 36

What is the role of surgery in osteomyelitis or PJI?

Answer 36

Removes necrotic tissue or infected hardware and improves antibiotic efficacy; critical for cure in many cases.

Question 37

What are the key goals in treating bone and joint infections?

Answer 37

Accurate diagnosis, appropriate antimicrobial therapy, surgical management when necessary, and long-term follow-up to monitor for relapse.

Question 38

What are the routes of infection for osteomyelitis and septic arthritis?

Answer 38

Hematogenous spread, contiguous spread from nearby tissue, and direct inoculation (e.g., trauma, surgery).

Question 39

What are the most common pathogens in bone and joint infections?

Answer 39

Staphylococcus aureus (MSSA and MRSA), Streptococcus spp., Enterobacterales, Pseudomonas aeruginosa, and occasionally anaerobes.

Question 40

How are bone and joint infections diagnosed?

Answer 40

Clinical signs, elevated inflammatory markers, imaging (MRI), and positive cultures from blood, bone, or synovial fluid.

Question 41

What are the treatment pillars for osteomyelitis and prosthetic joint infections (PJI)?

Answer 41

Source control (surgery or debridement) and prolonged antibiotic therapy.

Question 42

What is the preferred duration of therapy for osteomyelitis and septic arthritis?

Answer 42

Osteomyelitis: 4–6 weeks. Septic arthritis: 2–4 weeks depending on pathogen.

Question 43

Which oral antibiotics can be used for step-down therapy in bone and joint infections?

Answer 43

Linezolid, fluoroquinolones, TMP-SMX, doxycycline, clindamycin, and rifampin (for biofilm activity).