List some clinical presentations of acute bone and joint infections
Temperature
Pain, redness, swelling
Reduced mobility
Define SIRS
2+ of Temp less than 36 or more than 38 Heart rate more than 90 Resp rate more than 20 PaCO2 less than 4.3kPa WBC more than 12k or less than 4k
What is septic arthritis? How can it be introduced?
Infection of the joint space
Blood spread, direct innoculation or from infected bone
What are the main organisms that cause septic arthritis?
Staph. aureus
Streptococci
List diagnostic investigations for septic arthritis
Blood culture if pyrexial
Blood tests
Joint fluid aspirate for microscopy/culture
USS, XR, CT bone
What is the main empirical treatment for septic arthritis?
Flucloxacillin (Staph. aureus)
N.B. high-dose IV to maximise uptake
If there is a child under 5yrs old with septic arthritis, which antibiotic should be added and why?
Ceftriaxone for H. influenzae/Kingella cover
How long does antibiotic treatment for septic arthritis usually last?
2-4 weeks
Which organisms cause chronic osteomyelitis?
Mycoplasma
Pseudomonas
Salmonella
Brucella (goat’s milk)
Treatment and diagnosis of osteomyelitis is similar to septic arthritis. What is the key difference in terms of treatment length?
4-8 weeks duration of antibiotic treatment
Which organisms cause type 1 necrotising fasciitis?
Mixed anaerobes and other bacteria
Which organism causes type 2 necrotising fasciitis?
Group A Strep. (flesh-eating bacteria)
List the mainstay treatment for necrotising fasciitis
Surgical debridement
Pencillin + clindamycin
What is gas gangrene?
Spores forming in tissue, causing accumulation of gas bubbles
What is tetanus?
Neurotoxin produced by Clostridium tetani prevents release of neurotransmitters, causing locked jaw/spastic paralysis
When is vancomycin used empirically instead of flucloxacillin?
If MRSA, diptherioids, or penicillin-allergic
Why is clindamicin useful?
Antitoxin properties - effective against PVL, group A Strep.
Why do bacteria in biofilms pose a problem?
Resistant to immune system and antibiotics
Why are superficial wound swabs a waste of time?
Reflect skin flora rather than deep infection (coag neg Staph. are part of flora)
What is the main treatment for osteomyelitis?
Debridement/ drainage
Biopsy
Antimicrobials (IV)
What is the main treatment for diabetic foot ulcer?
Debridement
Flucloxicillin
What are the two main classifications of osteomyelitis
Acute/chronic
Haematogenous (in blood)/ contiguous (adjacent to infection source)
How is osteomyelitis typically investigated?
Imaging - XR/CT/MRI
Biopsy
Wound swab
Blood culture
What is the main management of prosthetic joint infection?
Remove prosthesis
6 week therapy
Re-implant after antibiotics
What are the main signs of septic arthiritis?
Sever pain
Red, hot, swollen
Reduced movement
When does chronic osteomyelitis usually develop?
After untreated acute osteomyelitis
What is the classical clinical sign of necrotizing fasciitis?
Crepitus
What is the main treatment for cellulitis?
Flucloxicillin and benzylpenicllin
What investigations are used in prosthetic joint infection?
CRP
Joint aspiration
Technetium bone scan
XR
What is osteomyelitis?
Infection of bone, including its marrow
What are the main mechanisms by which bone can become infected?
Penetrating trauma/surgeryHaematogenous spread
What is a sequestrum?
Dead segment of bone
What is the significance clinically of sequestrums?
Once one develops, antibiotics will not cure infection
Why do kids tend to get acute osteomyelitis more than adults?
Metaphyses have poor/slow blood flow which enables bacteria to accummulate easier
Which organism is the commonest cause of bone infections?
Staph. aureus
Chronic osteomyelitis cannot be treated by antibiotics alone. True/False?
True
Surgical debridement also usually required
Which group of people are particularly at risk of osteomyelitis of the spine?
IV drug users
Diabetics
Immunocompromised
List clinical features of osteomyelitis of spine
Constant insidious back pain
Paraspinal muscle spasm
Spinal tenderness
Systemic upset