Bone and Joint Infections Flashcards Preview

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Flashcards in Bone and Joint Infections Deck (32):
1

Osteomyelitis

Inflammation of bone and marrow due to infection

2

What are the different causes of osteomyelitis?

- Hematogenous
- Contiguous

3

What population is most likely to have hematogenous spread of osteomyelitis?

Children due to growing bone taking up more of the blood supply

4

What is the pathogenesis of acute osteomyelitis?

Infection at a focal point in the bone can lead to blockage of arteries leading to decalcification while proteolytic enzymes destroy bacteria leading to increased intramedullary pressure

5

What is the pathogenesis of chronic osteomyelitis?

Inadequate treatment of acute osteomyelitis leads to the continuation of the inflammatory process and eventual bone necrosis followed by new bone formation (involucrum) and possible sinus formation in the involucrum.

6

What is the cause of contiguous osteomyelitis?

Extension from proximal infection - examples are ulcers from diabetes or infection from trauma/surgery

7

Where does osteomyelitis spread in children?

Infection often spreads out to the skin

8

Where does osteomyelitis spread older patients?

Infection tends to stay in the bone

9

What are the typical pathogens of osteomyelitis?

- Staph
- Strep
- Enterococcus and Gram Negative Rods (more rare)

10

What is the the MOST common pathogen for osteomyelitis?

S. aureus

11

What is the most likely pathogen for osteomyelitis due to a puncture wound?

Pseudomonas

12

What is the most likely pathogen for osteomyelitis in those with sickle cell anemia?

Salmonella

13

What is the most useful lab test for diagnosis of osteomyelitis?

Bone biopsy with a culture

14

What is the best imaging to use for osteomyelitis?

MRI

15

A 60 yr old man with type 1 DM has a chronic ulcer over R sole of foot. It has been draining pus for weeks. No fevers, pain. On PE, he is AF. There is a draining sinus tract on R sole of foot. Culture from the pus grow E.coli and enterococcus faecalis. Placement of a steel probe through the sinus tract goes to bone. Which of the following should be done next?
• A.ObtainX‐ray
B. Obtain MRI
C. Start Vancomycin and Zosyn
D. Start oral clindamycin and levofloxacin
E. Schedule bone biopsy

E. Schedule bone biopsy

16

What is the probe bone test?

Probing to the bone in an ulcer requires no further testing to classify as osteomyelitis

17

What can 2 vertebrae back to back affected by osteomyelitis indicate?

Tuberculosis Osteomyelitis

18

Septic Arthritis

Rapid joint destruction, irreversible loss of function - often due to bacterial infection

19

How serious is septic arthritis?

EMERGENCY - 50% with permanent loss of function

20

What are some risk factors for septic arthritis?

- Age greater than 80
- Recent joint surgery
- IV drug use
- Endocarditis
- Joint diseases (RA/OA/Gout)

21

A 65 yr old woman with RA has a 1d hx of pain and swelling of the 3rd R PIP joint. Current Meds are: Prednisone, Methotrexate. On PE: T39.2, rest wnl. The joint is warm, erythematous, tender and has decreased range of motion (ROM). What do you do?:
A. Prescribe colchicine
B. Treat her for a RA flare
C. Perform diagnostic tap
D. Prescribe ampicillin

C. Perform diagnostic tap

22

What is the main diagnostic test for septic arthritis?

Diagnostic Tap

23

Does a negative Gram stain rule out septic arthritis?

NO

24

What are the main causes of septic arthritis?

- S. aureus
- Strep

Much less common:
- E. coli
- Neisseria
- Pseudomonas

25

What WBC levels increase risk for septic arthritis?

Higher WBC levels increase the risk fro septic arthritis

26

A 65 yr old woman with RA has a 1d hx of pain and swelling of the 3rd R PIP joint. Current Meds are: Prednisone, Methotrexate. On PE: T39.2, rest wnl. The joint is warm, erythematous, tender and has decreased ROM. Examination of purulent fluid aspirate from the joint is negative for crystals. Which of the following organisms is the most likely cause?

A.Strep pyrogenes
B.Strep agalactiae
C.Staph aureus
D.Pseudo aeruginosa
E. Salmonella Enteritidis

C.Staph aureus

27

What is the population for gonococcal arthritis?

Most common in sexually active individuals less than 30 yrs of age

28

What gender gets gonococcal arthritis more?

Females

29

What is the presentation triad of disseminated gonococcal infection?

- Dermatitis
- Tenosynovitis
- Migratory polyarthralgia or arthritis

30

25 yr old man from Hawaii had a 2d hx of severe R wrist pain. The pt is sexually active with multiple partners and infrequently uses condoms. On PE, his T38.9, HR: 100, BP: 100/70. Exam reveals erythema and swelling and decreased ROM of R wrist. His serum WBC in 18,000. What is the most likely causative micro‐organism?
A. Staph aureus
B. Strep agalactiae
C. Neisseria gonorrhea
D. Ebstein Barr Virus
E. Borrelia burgdorferi

C. Neisseria gonorrhea

31

What are symptoms of lyme arthritis?

Polyarticular, intermittent and relapsing arthritis - can be migratory

32

What is the most common site for lyme arthritis?

Knee

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