Bone infection

Question 1

RF for osteomylitis?

Answer 1

• IVDU
• immunosuppressed
• DM
• alcohol excess
• sickle cell
• bimodal age - early life, late life

Question 2

What bugs usually cause osteomylitis?

Answer 2

• staph aureus
• coagulase -ve staphylococcus
• E.coli (anaerobe)

Question 3

What organism causes osteomylitis in IVDU? Sickle Cell?

Answer 3

IDVU - p auerginosa

Sickle cell salmonella

Question 4

Sx of acute osteomyelitis? Chronic osteomyelitis?

Answer 4

acute 
-dull ache at infection site + aggrevated by movement 
-tenderness, warmth, erythema, swelling 
-systemic - fevers, rigors, sweats, malaise
chronic 
-Pain at site
-non-healing ulcer
-draining sinus 

Can also present as septic arthritis as pus invades joints space

Question 5

Imaging for osteomyelitis?

Answer 5

• Xray - not sensitive esp. in acute phase

- MRI - more sensitive but not necessarily diagnostic

Question 6

What other tests would you want to do in ?osteomyelitis?

Answer 6

• Bone biopsy

- blood cultures - most useful in acute beneficial for haematogenous OM

Question 7

Treatment for OM?

Answer 7

Surgical:

• debridement
• replacement or removal of hardware

Abx:

• first line commonly flucloxacillin 6/52
• tailored to MC&S
• prolonged length of course
• guided stopping by CPR & ESR dependent response

If TB Tx = 12 months

Question 8

what is septic arthritis? why is it a medical emergency?

Answer 8

• infection of a joint

- delayed treatment can lead to joint destruction and loss of function

Question 9

Most common cause of septic arthritis? + mechanism?

Answer 9

-Staph aureus

3 mechanisms

• trauma to joint
• spread from local infection
• blood borne

Question 10

RF for septic arthritis?

Answer 10

• prosthetic joint
• recent steroid injection
• DM
• pre-existing joint disease RA
• direct injury to joint
• RF for sepsis
• local skin breaks/ulcers

Question 11

What’s the criteria for diagnosing septic arthritis?

Answer 11

Kocher criteria:

• Fever >38.5
• non-weight bearing
• increase ESR
• increase WCC

Question 12

Cause of septic arthritis in previously fit young person?

Answer 12

-gonococcal - spread from gonorrhoeal genital, rectal or oral infection can be asymptomatic

Question 13

Sx of septic arthritis?

Answer 13

• hot painful swollen joint - similar to gout but have to rule out SA
• 90% monoarticular but can be poly
• knee > hip > shoulder involvement

Question 14

Ix for septic arthritis?

Answer 14

• always aspirate before starting Tx
• IV abx for 6-12 weeks
• pause immunosuppression
• repeat joint wash out if effusion present
• rest/splint/physio
• analgesia

Question 15

Risks following joint replacement?

Answer 15

• wound infection
• prosthetic infection
• dislocation
• VTE - 4 weeks LMWH

Question 16

Advice to a hip replacement patient to prevent dislocation?

Answer 16

• don’t flex greater than 90 degrees
• avoid low chairs
• DO NOT cross legs
• DO NOT sleep on back for 6 weeks