Septic Arthritis

Question 1

What is septic arthritis?

Answer 1

Infection of 1 or more joints caused by pathogenic inoculation of microbes

Question 2

How quickly can septic arthritis destroy a joint?

Answer 2

Under 24h

Question 3

Which joint is affected in >50% of cases?

Answer 3

The knee

Question 4

What is the first investigations?

Answer 4

Urgent joint aspiration for synovial fluid microscopy and culture, blood cultures

Question 5

What other investigations would you do?

Answer 5

CRP/ESR (raised)

Question 6

What is the main differential diagnosis?

Answer 6

Crystal arthropathies

Question 7

What management should you start if in doubt?

Answer 7

Empirical IV antibiotics until sensitivities are known - flucloxacillin

Question 8

When should you consider septic arthritis?

Answer 8

Any acutely inflamed joint

Question 9

What are the predominant organisms responsible?

Answer 9

Staphylococci, streptococci

Question 10

What are risk factors for septic arthritis?

Answer 10

Pre-existing joint disease, joint prostheses, IVDU, immunosuppression, alcohol misuse, diabetes, intra-articular corticosteroid injection, recent joint surgery

Question 11

How does septic arthritis present?

Answer 11

Hot, swollen, painful, restricted joint, fever