Septic Arthritis & Osteomyelitis Flashcards
Aetiology of septic arthritis:
DIRECT
- Trauma
- Post-op/ instrumentation
- Instrumentation
CONTIGOUS
HAEMATOGENOUS
- Sepsis
- Endocarditis
Chronic arthritis is a risk factor (abnormal joints)
Common organisms in septic arthritis:
Usually skin
But anything possible, from haematogenous spread.
Staph auerus and gonorrhoea most common.
GBS (neonate), GAS, pseudomonas, enterobacteriacae.
Diagnostic criteria for septic arthritis:
There is none.
No single test can rule in or out, including ‘typical’ synovial aspirate findings (…unless frank pus)
‘Kocher’s Criteria’ to help in KIDS with HIP presentations.
Empirical antibiotics in septic arthritis
Think, cover:
Skin
Gono
MRSA
________
Flucloxacillin IV 50mgkg (2g) Q6H
Plus
Ceftriaxone IV 50mg/kg (2g) daily (Gram Neg: gono, pseudom)
Plus
Vancomycin IV 25mg/kg (1g) BD (MRSA)
Complications of septic arthritis:
Sepsis
Osteomyelitis
Joint destruction/ chronic arthritis
Adhesive capsulitis
Growth arrest (kids)
Expected synovial fluid findings in septic arthritis:
WCC > 50,000
Polymorphs > 75%
Turbid
Crystals- no
Bacteria - yes.
Glucose- N or low.
… NOT diagnostic. Only frank pus is. Consider whole clinical picture.
‘Atypical’ presentations of septic arthritis:
Elderly and immunocompromised may not have many joint signs, or inflamm markers. Polyarticular more likely.
Gonorrhoeal often >1 joint.
Prosthetic
Imaging in Osteomyelitis:
MRI from day 1
CT from 3-5 days
XRAY from 2 weeks
BONE BIOPSY + culture
(Bone scan: not ED)
____________________
ACUTE:
- Periosteal reaction (incl. Codman’s Triangle)
- Focal lucencies/ resorption
- Gas in tissues
- Oedema, abscess
CHRONIC:
- Sequestra
- Involucrum
- Cloaca + sinus
Management of Osteomyelitis:
Surgical and ID consults
Flucloxacillin IV, 50mg/kg (2g) Q6H
OR Tazocin if immunocompr
PLUS Vancomycin if MRSA
