septic arthritis

Question 1

what is septic arthritis?

Answer 1

infection of a joint

usually caused by S aureus , streptococcus, gonorrhoea (if sexually active) and salmonella (esp in sickle cell)

Question 2

what are the risk factors for septic arthritis?

Answer 2

• age >80yrs
• pre existing joint disease
• diabetes mellitus
• chronic renal failure
• hip or knee proshesis
• IV drug use

Question 3

what are the clinical features for septic arthritis?

Answer 3

• single swollen joint causing severe pain
• pyrexia
• red, swollen and warm joint with pain on active and passive movements. May see effusion.
• rigid joint and patient will be unable to weight bear.

Question 4

what are the differential diagnosis for septic arthritis?

Answer 4

• Bursitis
• reactive arthritis
• RA
• haemarthrosis (bleeding into joint space)
• OA flare up

Question 5

what investigations are done for septic arthritis?

Answer 5

• routine bloods including ESR an urate levels
• blood cultures should be sent, especially if evidence of sepsis
• aspirate joint before antibiotics are given and send joint fluid for gram stain

Question 6

what imaging can be done for septic arthritis?

Answer 6

• plain radiograph
• USS to help joint aspiration
• CT/MRI to asses joint damage or joint infections

Question 7

how can septic arthritis be managed?

Answer 7

• antibiotic treatment, 2 weeks IV and 4 weeks long term.

infected native joints require surgical irrigation and debridement in theatre to aid source control.

Question 8

what are the complications of septic arthritis?

Answer 8

osteoarthritis and osteomyelitis. Early intervention and management will reduce the risk of developing these complications.