Septic arthritis

Question 1

Common cause septic arthritis in adults?

Answer 1

• S. aureus.
• Consider Coag -ve Staph in pts with Hx joint replacement.
• Consider N. gonorrhoea

Question 2

RFx septic arthritis?

Answer 2

• Age >80
• PMHx: DM, RA
• Joint: prosthetic, recent surgery/injection
• Skin ulcer/infection
• IVDU
• Alcoholism

Question 3

Describe the clinical presentation of septic arthritis.

Answer 3

Inability to weight bear, localised joint pain, erythema, warmth, swelling, pain on active and passive ROM.

Question 4

Ix in septic arthritis?

Answer 4

• X-ray (exclude fracture/ tumour / metabolic bone disease)
• Bloods: CRP, WCC, culture
• Aspirate: WBC with >90% Neut, decreased glucose (relative to blood), Gram stain +ve, culture.

Question 5

Rx septic arthritis?

Answer 5

• IV ABx (empirical: vancomycin G+ve, clindamycin G-ve).
• Small joint: needle aspiration
• Major: urgent decompression and surgical drainage

Question 6

What are the X-ray findings in septic joints?

Answer 6

Early (0-3d): normal. May show soft tissue swelling of joint space widening from localised oedema.
Late (4-6d): joint space narrowing and destruction of cartilage.

Question 7

Complications of septic arthritis?

Answer 7

• ABx allergy
• Osteomyelitis
• Joint destruction

Question 8

Which factors indicate poor prognosis in septic arthritis?

Answer 8

• Older age
• Pre existing joint disease
• Joint prosthesis