Exam 3: Bone and Joint Infections

Question 1

What is osteomyelitis?

Answer 1

Infection of the bone

-causes inflammation of the bone marrow and surrounding bone

Question 2

What is septic arthritis?

Answer 2

Inflammatory reaction with the joint tissue and fluid due to a microorganism

Question 3

What is prosthetic joint infection?

Answer 3

Infection of a prosthetic joint and joint fluid

Question 4

What test do we use to identify bone infections?

Answer 4

Blood cultures

Question 5

What is the most common pathogen in bone/joint infections?

Answer 5

Staphylococcus aureus

Question 6

How is antibiotic therapy different with bone and joint infections?

Answer 6

Need therapy for longer durations and higher doses

-Often use IV therapy for the entire duration

Question 7

What is the typical treatment duration for osteomyelitis?

Answer 7

4-8 weeks

Question 8

What is the typical treatment duration for septic arthritis?

Answer 8

2-4 weeks

Question 9

What is the typical treatment duration for prosthetic joint infections?

Answer 9

6-12 weeks

Question 10

What are the 3 pathways of osteomyelitis pathogenesis?

Answer 10

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

Question 11

What is the standard of care for diagnosis of osteomyelitis?

Answer 11

MRI

Question 12

What are the two components of osteomyelitis treatment?

Answer 12

Surgical Intervention

Antibiotic Therapy

Question 13

When initiating antibiotic therapy for a patient with osteomyelitis, what is important to consider before initiating?

Answer 13

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

Question 14

What treatment options do we have for empiric antibiotic therapy for osteomyelitis?

Answer 14

Cefazolin
Ceftriaxone
Cefepime
Piperacillin/Tazobactam
Ampicillin/Sulbactam
Meropenem
Ciprofloxacin
Levofloxacin

+ MRSA Coverage:

Vancomycin
Daptomycin
Linezolid

Question 15

If anaerobic coverage is desired in osteomyelitis treatment, what drug can we add?

Answer 15

Metronidazole

Question 16

What is the typical duration of osteomyelitis treatment?

Answer 16

4-8 weeks

Question 17

What is the length of treatment for vertebral osteomyelitis due to MRSA?

Answer 17

8 weeks

Question 18

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?

Answer 18

2-5 days

Question 19

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?

Answer 19

1-2 weeks

Question 20

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?

Answer 20

3 weeks

Question 21

If a patient has a diabetic foot infection related to osteomyelitis and they do not have any resection, how long is treatment duration?

Answer 21

6 weeks

Question 22

What are the 2 oral options for osteomyelitis?

Answer 22

Rifampin

Dalbavancin

Question 23

When is rifampin an option for osteomyelitis treatment?

Answer 23

If we are treating streptococcus, MSSA, or MRSA

*not for Gram -

Question 24

What is the dosing strategy for dalbavancin in osteomyelitis?

Answer 24

2-dose strategy

Question 25

What is the half-life of dalbavancin?

Answer 25

346 hours

Question 26

Besides staph aureus, what is another common bacteria that can cause septic arthritis?

Answer 26

Neisseria gonorrhoeae

Question 27

What are the common signs of septic arthritis?

Answer 27

Joint pain, Decreased range of motion, Swelling, Erythema, Warmth, Fever, Chills *Monoarticular in the majority of cases

Question 28

What test is normally used to diagnose septic arthritis?

Answer 28

Arthrocentesis -get sample of purulent, low viscosity synovial fluid -PMN count > 50,000 is positive

Question 29

What is the treatment for septic arthritis?

Answer 29

Same as osteomyelitis

Question 30

What is the typical duration of septic arthritis treatment?

Answer 30

2-4 weeks

Question 31

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

Answer 31

4 weeks

Question 32

What is the treatment duration for Streptococci septic arthritis treatment?

Answer 32

2 weeks

Question 33

What is the treatment duration for N. gonorrhoeae treatment?

Answer 33

7-10 days

Question 34

What are the symptoms of a prosthetic joint infection?

Answer 34

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

Question 35

What are the 3 primary types of surgical intervention in prosthetic joint infections?

Answer 35

1. Debridement and retention of prosthesis 2. 1-stage exchange 3. 2-stage exchange

Question 36

What are the benefits and downsides of the debridement and retention of prosthesis surgical approach in prosthetic joint infections?

Answer 36

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

Question 37

What is the 1-stage exchange surgical approach to prosthetic joint infections?

Answer 37

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

Question 38

What is the 2-stage exchange surgical approach to prosthetic joint infections?

Answer 38

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

Question 39

When would we use rifampin in prosthetic joint infections?

Answer 39

Retention of prosthesis or 1-stage exchange