Septic arthritis

Question 1

Two causative organisms of septic arthritis?

Answer 1

staph
gonococcus
streps

Question 2

Name two conditions that predispose to septic arthritis development

Answer 2

 Joint disease (e.g. RA)
 Chronic renal failure
 Immunosuppression (e.g. DM)
 Prosthetic joints

Question 3

Two symptoms of septic arthritis

Answer 3

 Acutely inflamed tender, swollen joint
 ↓ROM
 Systemically unwell

Question 4

Two investigations for septic arthritis

Answer 4

 Joint aspiration ↑↑ WCC (e.g. >50,000/mm 3 ): mostly neutrophils
 ↑ESR/CRP, ↑WCC, Blood cultures
 X-ray

Question 5

Two aspects of septic arthritis management

Answer 5

 IV Abx: vanc + cefotaxime
 Consider joint washout under GA
 Splint joint
 Physiotherapy after infection resolved

Question 6

Two complications of septic arthritis?

Answer 6

  Osteomyelitis 
  Arthritis 
  Ankylosis: fusion
loss of cartilage leading to osteoarthritis in later life
severe sepsis
septic shock

Question 7

Two differentials for septic arthritis

Answer 7

 Crystal arthropathy

 Reactive arthritis

Question 8

Three risk factors for septic arthritis

Answer 8

trauma, DM, previous arthritis, immunosuppression, bacteremia- colonoscopies, sickle cell anemia, prosthetic joint

Question 9

Why is synovial fluid a good environment for bacterial growth?

Answer 9

no basement membrane, close relationship to blood vessels

Question 10

Which is the most common joint affected in septic arthritis?

Answer 10

knee

Question 11

Which condition is strongly associated with polyarticular septic arthritis?

Answer 11

RA

Question 12

Two findings in synovial fluid aspirate would be suggestive of septic arthritis?

Answer 12

high WBC count, majority polymorphic neutrophils, low glucose

Question 13

Which bacteria that can be transmitted through sex can result in polyarthritic sepsis?

Answer 13

gonorrhoea- neisseria gonnorrhoea

Question 14

Why do prosthetic joints increase the risk of septic arthritis?

Answer 14

absence of immune protective tissue thus fewer bacteria to establish sepsis, poor vasculature where bacteria can set up biofilm, cement inhibits phagocytosis and lymphocyte/complement function

Question 15

What are the two modes of spread that cause septic arthritis following surgery ?

Answer 15

local and haematogenous spread

Question 16

What are the two surgical options available for infected prosthetic joints?

Answer 16

1. DAIR- Debride, Antibiotics, Implant Retained 2- Take the infected joint out 3. (possible amputation)

Question 17

Antibiotic choices for septic arthritis?

Answer 17

fluclox
vanc if MRSA
clindamycin if penicillin allergy