Septic arthritis

Question 1

Describe septic arthritis?

Answer 1

• Most rapid and destructive bone disease
• Age is the greatest mortality risk factor

Question 2

Describe the pathogenesis of septic arthritis?

Answer 2

Haematogenous spread from infections of skin/upper RT

Question 3

What are the clinica features of septic arthritis?

Answer 3

• Acute monoarhritis and fever
• Hot, swollen, red joint
• Pain with rest and movement
• Mostly hip/knee

Question 4

When should septic arthritis be considered?

Answer 4

• Acutely inflamed joint
• >50% cases are in the knee

Question 5

Mortality rate of SA?

Answer 5

Up to 11%

Question 6

Risk factors for SA?

Answer 6

• Pre-existing joint disease, recent surgery, prosthetic joints
• DM, immunosuppression
• Chronic renal failure
• IV drug use

Question 7

Describe the investigations into SA?

Answer 7

• Urgent joint aspiration
  
  • Synovial fluid microscopy and culture
  • Clear, turbid or blood stained
• Radiographs and CRP may be normal
• Serial CRP/ESR can monitor treatment

Question 8

Alternative differentials for SA?

Answer 8

Crystal arthropathies

Question 9

Describe the common causative organisms for SA?

Answer 9

• S. aureus
• N. gonococcus (young sexually active)
• Streptococci
• Gram negative bacilli

Question 10

Treatment for SA?

Answer 10

• ​Flucloxacillin
  
  • Clindamycin if pen-allergic
  • Vancomycin if MRSA risk
• 2 weeks IV then 4 weeks PO
• Analgesia, ice packs
• Needle aspiration to decompress
• Arthroscopic lavage may be required

Question 11

What is the most likely cause of SA in:

Adults?

Young sexually active adults?

Answer 11

S. aureus

Gonnococus

Question 12

Describe the diagnostic criteria for the diagnosis of septic arthritis?

Answer 12

• Kocher criteria
  
  • Fever > 38.5^oC
  • Non-weight bearing
  • Raised ESR
  • Raised WCC