Osteomyelitis Flashcards
What is osteomyelitis?
Any inflammatory condition of the bone which involves the haversial systems, volkmanns, cortex and generally the marrow and periosteum
Osteitis, discospondylitis, epiphysitis: inflammation of bone, disc, epiphysis only
What is the source of infection of osteomyelitis?
1) iatrogenic following surgery (70%)
2) Haematogenous
3) Extension from local infected lesion
4) External source
5) Nosocomical (hospital infections)
Predisposing causes?
1) Vascular compromise
2) iatrogenic contamination
3) Dead space haematoma at fracture site
4) destructive fixation devices (IM pins)
5) immunosuppression - corticosteroids etc
6) Systemic problems (hypoproteinemia, DM, systemic disease)
7) Break in sterility
8) Length of surgery
9) Remove infections (e.g. otitis, cystitis)
10) Old age
11) Length of hospitalisation
12) Antimicrobial therapy
13) Surgical drains, urinary catheters, intravenous cannulas
14) Diagnostic procedures
What is a sequestrum and involucrum?
Sequestrum: Necrotic bone fragment - area of dense bone
Involucrum - avascular wall of fibrous tissue and sclerotic bone, bone proliferation
Implants susceptibility to infection?
Smooth titanium < stainless steel < porous coated titanium < porous coated cobalt chrome
Clinical signs of acute osteomyelitis?
- history (e.g. recent surgery)
- pain, swelling, pyrexia, lameness, abscess
- NO CHANGES on radiograph
15-30% of acute cases become chronic
Clinical signs of chronic osteomyelitis?
- history
- less severe clinical signs; lameness, pain, sinuses
- radiographic changes evident
Radiographic changes of chronic osteomyelitis?
1) soft tissue swelling
2) periosteal new bone ragged and extensive
3) focal bone lucenceis (rare; especially in metaphyses or around implants)
4) bone lysis becomes widespread (more chronic cases)
5) Sequestrae develop - area of increased density in bone surrounded by a zone of decreased density or osteolysis
Causative agents?
Staphylococcus aureus
Streptococcus
E.coli
Proteus
Pasteurella
Pseudomonas
Nocardia
Mycobacteria
Cryptococcus
Aspergillus
Treatment of acute osteomyelitis?
1) Antibiotics - culture and sensitivity (FNA, swab, bone biopsy)
2) Assess and adress any fracture instability
3) Debridement - if not responding to AtB
4) Drainage (if necessary)
Follow up XR - changes can lag several weeks
Treatment for chronic osteomyelitis?
1) Identify cause and remove - sequestrum
2) lavage (50-70 psi)
3) Primary or secondary closure
4) Bacterial swab for sens/spec at END of debridement
5) Assess fracture stability - remove implants and replace as necessary
what is glycocalix and why do we care?
Glycocalix is a gelatinous mucinous carbohydrate layer where bacteria can lie dormant and be protected from antibiotics
It can cover our implants
-> All implants may need removal for the infection to resolve
