Septic Arthritis Flashcards
What is it?
Infection within the synovial fluid and joint tissues
What is the pathology of SA?
Joint is invaded by haematological spread/eruption of bone abscess or penetrating wound
Infection spreads throughout wound and destroys cartilage
Pus erupts from joint leading to abscess formation
When healing the articular surfaces are exposed and could fuse together leading to ankylosis
What are risk factors?
Extremes of age Pre-existing joint disease IV drug users DM/immunosuppressed Recent operation Infection elsewhere RA
What are common causative organisms?
Staph aureus
Disseminated gonococcal infection in young adults
Strep pneumoniae/h.influenzae in young children
What are the symptoms?
Hot, swollen, tender joint Monoarticular Rapid onset pain Pain on movement Decreased range of movement Systemic symptoms -fevers -rigors -tachycardia -tachypnoea
What investigations are needed?
Bloods
- FBC= WCC raised
- U&Es, LFTs=look at function
- Uric acid- for CAA
- Blood cultures x2
- CRP
Full septic screen
Joint aspiration
- for gram stain/culture
- can be cloudy/blood stained
- gram stain positive in 50%
- if gonococcal then genital tract culture too
- if joint not easily accessible/prosthetic then aspirate in theatre under image guidance
Joint XR
- must be completed within 2wks to look for structural damage
- initially shows soft tissue swelling and joint space widening due to effusion
- late on narrow joint spaces as cartilage is destroyed
What are some differentials?
OA
Crystal Associated arthritis
RA
Seronegative spondyloarthropathies
What is the management?
Admit
A-E
Sepsis 6
- High flow oxygen
- urine output
- blood cultures x2
- measure lactate
- IV fluids
- IV abx (after aspiration, 2g fluclox 6hrly)
Inform senior Pain relief Early in theatre washout Rest joint IV abx for 2-3wks and then oral for 6wks