Bone and Joint Infection Flashcards Preview

Musculoskeletal > Bone and Joint Infection > Flashcards

Flashcards in Bone and Joint Infection Deck (37):
1

Calor

Heat

2

Dolor

Pain

3

Tumor

Swelling

4

Functio laesa

Loss of function

5

Sequestrum

When dead bone becomes detattched from healthy bone

6

Gold Standard test for osteomyelitis?

Bone culture

7

X-ray signs of osteomyelitis

Patchy osteopenia and signs of bone destruction

8

Why should you give special consideration to osteomyelitis of vertebral bodies?

It can lead to permanent neurological defects
Neurologic deficits are late findings secondary to vertebral body collapse or epidural abscess. MRI is the best imaging study for osteomyelitis

9

What is diskitis

diskitis is an infection in the intervertebral disc space that affects different age groups, but usually spontaneously affects children under 8 years of age

10

What is an involucrum?

An involucrum is a complication of osteomyelitis and represents a thick sheath of periosteal new bone surrounding a sequestrum

11

Useful blood tests in osteomyelitis?

CRP and plasma viscosity
(blood cultures, white cell count and ESR are occasionally useful)

12

Causes of osteomyelitis

In most instances, osteomyelitis results from haematogeneous spread, although direct extension from trauma and/or ulcers is also relatively common (especially in the feet of diabetic patients).

13

Location of osteomyelitis

neonates: metaphysis and/or epiphysis
children: metaphysis
adults: epiphyses and subchondral regions

14

Organisms usually causing osteomyselitis

Staph aureus
Haemophilus in children

15

Causes of acute osteomyelitis

Staph aureus
Haemophilus in children

16

Tests used if chronic osteomyelitis is suspected?

X-ray and MRI

17

Involucrum

An involucrum is a complication of osteomyelitis and represents a thick sheath of periosteal new bone surrounding a sequestrum.
Often seen in chronic osteomyelitis

18

How does septic arthritis arise?

From inoculation
From metaphyseal spread
Direct haematogenous

19

Treatment for cellulitis

Best guess antibiotics to cover staph and strep
Lecturer used flucloxacillin and benzylpenicillin

20

Tests used if you suspect an infected arthroplasty

CRP
Joint aspiration
Bone scan (Technetium 99)
X ray

21

Prophylaxis for osteomyelitis surgery/ bone surgery to prevent osteomyelitis

Easily measureable:
-Clean air theatres
-Local antibiotics
-Systemic antibiotics
-Duration of surgery

Not easily measurable:
-Neat surgery
-Quality of hand washing
-Theatre discipline

22

Clinical features of infection

Pain
Swelling
Heat
Tenderness
Resistance to active or passive movement

23

Diagnosis of infection

Raised temperature
Raised white cell count
Raised CRP

24

Complications of infection (cartilage and ...)

-Destruction of articular cartilage, leading to pain and stiffness
-Bone or fibrous ankylosis

25

Prophylaxis for orthopaedic surgery

Laminar flow
24 hours antibiotics starting with induction
Antibiotics in cement

Co-amoxiclav
Flucloxacillin + gentamicin
Clindamycin
Co-trimoxazole

26

Antibiotics used as prophylaxis for orthopaedic surgery

Co-amoxiclav
Flucloxacillin + gentamicin
Clindamycin
Co-trimoxazole

27

CFGCC antibiotic prophylaxis for orthopaedic surgery

-Co-amoxiclav
-Flucloxacillin & gentamycin
-Clindamycin
-Co-trimoxazole

28

Which 'bugs' do you need to provide prohpylaxis for in orthopaedic surgery?

Staphylococcus aureus
Staphylococcus epidermidis (coagulase negative staphylococcus)

SA causing TKR/THR infection
96% sensitive to current prophylaxis

CNS causing THR/TKR infection
72% resistant to Flucloxacillin
40% resistant to Gentamicin
32% resistant to entire prophylactic regime

Current strategy tailored towards least problematic bug

29

Organisms that cause early post operative infection?

Staph aureus
Streptococcus
Enterococcus

30

Organisms that cause delayed (low grade) infection
3-24 months

Coagulase negative staphylococci
P. acnes

31

Organisms that cause late infection (>24 months)

Staph. aureus
E. coli

32

SIRS
(systemic inflammatory response syndrome)

SIRS: two or more of:
Temperature >38ºC or 90 beats/min
Respiratory rate >20 breaths/min or PaCO2 12,000 cells/mm3 or <4,000 cells/mm3

33

Chronic infection, SIRS and antibiotics?

SIRS is usually absent in chronic infections, if it is absent then there is no need for immediate antibiotics

34

Bacteria usually responsible for acute and chronic infections

Acute primary infections
S. aureus
Streptococcus spp

Chronic infections
CoNS
Propionibacteria

35

Why can CRP be confusing in bone and joint infection?

Not always elevated, especially in chronic infections
Influenced by underlying disease and acute stress (surgery)
Only useful in monitoring cases without major surgery

36

Sign standards for surgery prophylaxis antibiotics

The first dose must be given within 30 minutes of the start of surgery
Prophylaxis should not continue >24h after surgery

37

What do you do if there is MRSA pre-op when you screen for it?

Decolonise if positive