Septic Arthritis

Question 1

What are RF for septic arthritis?

Answer 1

1. Underlying joint disease
2. Prosthetic joint
3. Age
4. Immunosuppression
5. Contiguous spread
6. Exposure to ticks

Question 2

What are common causative agents for SA?

Answer 2

1. Staph aureus
2. Streptococci
3. Neisseria gonococcus
4. Grave -ve bacilli
   Staph aureus >30 yrs
   Neisseria gonorrhoea <30 yrs

Question 3

What are symptoms and signs for SA?

Answer 3

1. Hot swollen, painful, restricted joint
2. Acute presentation
3. Single, large joint
4. Fever
5. Acute monoarthritis

Question 4

What are some DDx for SA?

Answer 4

1. Osteoarthritis
2. Psoriatic arthritis
3. RA
   Gout
4. Pseudogout
5. Hemarthrosis
6. Trauma
7. Bursitis
8. Cellulitis
9. Lyme disease
10. TB, extrapulmonary

Question 5

When should you assume SA?

Answer 5

Hot, swollen, acutely painful joint with restriction of movement is septic arthritis until proven otherwise, even in absence of fever

Question 6

What synovial fluid investigations do you do?

Answer 6

1. Synovial fluid sample, gram stain, polarising microscopy
2. Synovial fluid culture and sensitivities
3. Synovial fluid WCC

Question 7

What bloods are done for SA?

Answer 7

1. Blood culture
2. WCC
3. ESR
4. CRP
5. U+Es
6. LFTs

Question 8

What imaging is done for SA?

Answer 8

1. Plain X ray

2. US

Question 9

Why are all these bloods and cultures taken?

Answer 9

Check for antibiotic sensitivity

Question 10

What is the management plan for SA?

Answer 10

Empirical IV Abx 2 weeks + 4 weeks oral Abx
• Cover S.aureus and Streptococcus spp
• Adapt after MC&S

Question 11

What are possible complications of SA?

Answer 11

1. Antibiotic associated allergic reaction
2. Osteomyelitis
3. Joint destruction

Question 12

What is the mortality of SA like?

Answer 12

Mortality rate up to 11%

Question 13

What is the cause of septic arhtirits?

Answer 13

Caused by current infection (haematogenous spread or direct inoculation)

Question 14

What are RF for infection?

Answer 14

1. IV drug use
2. diabetes
3. immunosuppression

Question 15

What are RF for joint damage?

Answer 15

1. Rh arthritis
2. prosthetic joint
3. gout

Question 16

What is the aspirate like in septic arthritis?

Answer 16

1. Turbid
2. yellow
3. low viscosity fluid
4. Raised WCC (neutrophils >90%)

Question 17

What do you need to stop in SA?

Answer 17

any biologic therapies e.g., TNF alpha inhibitors (12 months or forever if prosthetic joint)

Question 18

What is general management for septic arthritis?

Answer 18

• Antibiotic
• Joint aspiration
• Analgesia

Question 19

What is the Abx regimen for SA?

Answer 19

Flucloxacillin 4-6 weeks (longer if complicated); if penicillin-allergic then use clindamycin instead.

Question 20

What is the Abx regimen for SA with MRSA suspected?

Answer 20

Vancomycin (or teicoplanin) for 4-6 weeks (longer if infection complicated)

Question 21

What is the Abx regiment for SA If suspecting gonococcal arthritis or Gram-negative infection?

Answer 21

1. cefotaxime (or ceftriaxone)
2. treat Gram-negative infections for 4-6 weeks (longer if infection complicated)
3. treat gonococcal infection for two weeks