Septic Arthritis Flashcards
When should you consider septic arthritis?
In any acutely inflamed joint
What is the danger of septic arthritis?
It can destroy a joint in under 24hrs
When might the inflammation in a septic joint be less obvious?
In immunocompromised patients, or if there is underlying joint disease.
Which joint is most commonly involved?
The knee in >50% of cases
What are the risk factors for septic arthritis?
1) Pre-existing joint disease (especially RA)
2) Diabetes Mellitus
3) Immunosuppression
4) Chronic renal failure
5) Recent joint surgery
6) Prosthetic joints (infection here is particularly difficult to treat)
7) IV drug abuse
8) Age >80 yrs
What is the key investigation for suspected septic arthritis?
Joint aspiration for synovial fluid microscopy and culture.
Blood cultures may be helpful for guiding antibiotic choice
What is the main differential diagnosis for septic arthritis?
The crystal arthropathies
What use are plain radiographs and CRP levels?
They are not definitive as they may both appear normal
Wha is the main question to ask with septic arthritis?
“How did the organism get there?”
Immunosuppression?
A focus of infection e.g. indwelling lines etc.
Infected skin
Pneumonia - 50% of patients who present with pneumococcal arthritis have it
What is the treatment for septic arthritis?
Start empirical antibiotics if in doubt (check hospital policy), though after obtaining the aspirate first.
What are the common causative agents in septic arthritis?
Staph aureus
streptococci
Neisseria gonococcus
Gram -ve bacilli
What are the common choices of antibiotics to treat septic arthritis?
- flucloxacillin 1g 6hr I.V. (clindamycin if penecillin allergy)
- vancomycin 1g 12hr I.V. if MRSA (or history of..)
- Cefotaxime 1g 8hr I.V if gonococcal or Gram -ve
- If HIV +ve look for atypical mycobacteria and fungi
What are the possible non-pharmacological treatments for septic arthritis?
Ask for orthopaedic advice for consideration of arthrocentisis, lavage and debridement.
Splint, analgesia and physio.
