Bone and Joint infection 18/10/18 Flashcards
What are the five principles of inflammation?
Tumour Rubor Dolor Calor Functiono Laesa
What blood tests are useful?
CRP
Plasma Viscosity
What imaging is useful to diagnose infection?
X-ray
MRI
Technetium scan
What is the only thing that can properly diagnose the infection?
Surgically getting a specimen of the organism
What does a bone scan show?
Increased osteoblast activity
What can an MRI show in bone infection?
Fluid
Abscess
What is more useful MRI or X-ray?
MRI
What is the most common cause of osteomyelitis?
Post traumatic/Open fracture
Innoculation
What kind of osteomyelitis may occur in children and the immunosuppressed?
Haematogenous
What are some infecting organisms causing osteomyelitis?
Staph aureus
Haemophilus in children
What imaging is better for osteomyelitis?
MRI
Can show changes before x-ray
What must happen when pus is present?
Let it out
How does osteomyelitis occur?
Damage to endothelial vessels in bone - thrombus forms - bacteria settles
What are the two paths of chronic osteomyelitis?
Sclerotic reaction
Pus goes in different directions
-Into joint = septic arthritis
-Into periosteum = bone death over a wider area, new bone begins to form under pereosteum
What is useful for treating and diagnosing chronic osteomyelitis?
Blood tests are unhelpful
Plain X-ray and MRI
Do patients with chronic osteomyelitis require surgery?
Not always
Only if curative
What is involucrum?
Bone forming under periosteum?
How can septic arthritis begin?
From inoculation
From metaphyseal spread
Direct haematogenous
What is the patchy appearance (mottled) on x-ray?
Gas
What does gas on x-ray suggest?
Necrotising fascitis
How is cellulitis diagnosed and treated?
Can’t get a sample as no pus
Guess antibiotics to cover staph and strep
What 2 antibiotics can be used for cellulitis?
Flucloxacillin
Benzylpenicillin
How is necrotising fascitis treated?
SURGERY
Antibiotics to follow but will not cure
What is discitis?
Septic arthritis within the disc space
When are best guess antibiotics okay to use?
When obtaining a sample would be too difficult
When there is a large chance of a certain organism (staph) being the cause
How common is infected arthroplasty?
Should be no more than 1%`
What are two questions for infected arthroplasty?
Was there ever a wound problem
Has it ever been pain free
What are tests for infected arthroplasty?
CRP
Joint aspiration
Bone scan
X-ray
What is the presentation of an infected joint replacement?
Low grade
Slightly hot
Slight niggling pain
How successful are the one and two stage revsion surgeries for infected joint replacement?
1 stage - 70-80%
2 stage - 80-90%
What is prophylaxis for surgery to prevent infection?
Clean air theatres Laminar flow Local antibiotics - 24 hours before Systemic antibiotics - in cement Duration of surgery
What antibiotics may be used as prophylaxis?
Co-amoxiclav
Flucloxacillin + Gentamicin
Clindamycin
Co-Trimoxazole
