Septic Arthritis

Question 1

What happens in septic arthritis?

Answer 1

Acutely inflamed joint following infection
Septic arthritis can destroy a joint in <24h.
Knee is affected in >50% of cases

Question 2

What are the risk factors of septic arthritis?

Answer 2

Pre-existing joint disease (RA)
Diabetes mellitus
Immunosuppression 
Chronic renal failure
Prosthetic joints 
IV drug abuse 
Pneumonia
Age >80 years

Question 3

What are the investigations of septic arthritis?

Answer 3

Urgent joint aspiration for synovial fluid microscopy and culture
ESR, CRP & WCC
Blood culture
Ultrasound
X-Ray: may show joint space widening, subluxation

Question 4

What are the common organisms behind septic arthritis?

Answer 4

Staph aureus
Streptococci
N. gonococcus

Question 5

What are the signs and symptoms of septic arthritis?

Answer 5

Warmth
Redness
Effusion
Pain 
Decreased function 
Decreased range of movement

Question 6

What is the management of septic arthritis?

Answer 6

After investigations give broad spectrum antibodies
Once cultures come back, tailor ABx to the culture.

Consider flucloxacillin if staph aureus

Consider vancomycin IV plus a cephalosporin if MRSA risk

For suspected gonococcus or meningococcus consider ceftriaxone