SEPTIC ARTHRITIS

Question 1

What is septic arthritis?

Answer 1

Inflammation of a joint caused by a bacterial infection. These bacteria have entered a wound and travelled through blood to affected joint. If left untreated can become life-threatening and can lead to permanent joint damage

Question 2

What is treatment and recovery?

Answer 2

You’ll need to take antibiotics and should completely recover, although some people experience persistent limited movement in affected joint.

Question 3

What is the epidemiology?

Answer 3

Not majorly but incidence of prosthetic joint infection ranges from 1.5-2.5% procedures

Question 4

It often affects people who have just had what procedure?

Answer 4

prosthetic joint fitted

Question 5

What is the most common cause?

or other organisms

Answer 5

staph aureus

Streptococci, other staph, neisseria gonorrhoea, haemophilus influenza

Question 6

What are the risk factors?

Answer 6

• Pre-existing joint disease – esp. RA
• Diabetes
• Immunosuppresed (esp. HIV)
• Chronic renal failure
• Prosthetic joints (where infection is particularly diff to Rx)
• Increasing age
• Joint surgery

Question 7

What are the symptoms?

Answer 7

• Single swollen joint with pain on active and passive movement
• Often knee but can be wrists, ankles and hips too
• Fever and rigors
• Red, hot and very painful – esp. in previously fit people. May be more masked in elderly and immunosuppressed
• Unwillingness to move affected joint – limp, refusal to weight bear

Question 8

What are the signs?

Answer 8

• Swollen, warm, tender and exquisitely painful on movement
• Effusion may be obvious
• May get abscess around joint
• Signs less marked or poorly localised in elderly, immunocompromised and drug abusers

Question 9

What investigations would you do?

Answer 9

• Urgent joint aspiration for synovial fluid microscopy and culture and gram staining
• Leukocytosis is usual, unless the person is severely immunocompromised
• Plain radiogram and CRP may be normal so not usually used
• Blood cultures – for antibiotic guidance

Question 10

What is the treatment?

Answer 10

• IV antibiotics – empirical until sensitivities are known. Check with micro. If in doubt give IV antibiotics anyways
• S. Aureus/Streps/ N. Gonococcus and gram –ve bacilli – FLUCLOXACILLIN 0.5-1g/6hr IV (Vancomysin in MRSA +ve)
• Usually 2 weeks IV then 4 weeks PO but ask micro
• Ask orthopaedic advice for consideration of arthrocentesis, lavage and debridement esp. if prosthetic joint.
• Splint to immobilize joint for 48hr then physio

Question 11

What are the differentials?

Answer 11

• RA, osteoarthritis, vasculitis, gout and Pseudogout
• Drug induced arthritis
• Reactive arthritis
• Lyme disease
• Viral arthritis
• Infective endocarditis