Septic Arthritis (Acute Hot Joint)Emergency

Diabetic 58-year-old; 2 days of a hot, swollen, very painful right knee, cannot bear weight or move it; T 38.4 °C; WBC 16,000, CRP 180 mg/L

• Fever with a hot, immobile joint
• Prosthetic joint
• Septic shock
• Multiple joints with S. aureus bacteraemia

• Gout / pseudogout (crystals)
• Reactive arthritis
• Gonococcal arthritis
• TB arthritis (chronic, India)
• Haemarthrosis
• Cellulitis or bursitis over the joint

• Admit: Every suspected septic arthritis
• ICU: Septic shock, multiorgan failure
• Surgery: All septic joints need drainage — washout or serial aspiration; prosthetic joints to orthopaedics

• S. aureus causes most septic arthritis; mortality is ~10% and joint destruction begins within days.
• Risk factors: age >80, diabetes, RA, prosthetic joint, recent joint surgery or injection, skin infection, IV drug use.
• Gout, pseudogout and reactive arthritis mimic it — the aspirate decides.

• Start antibiotics before aspirating a stable patient (culture yield falls)
• Accept crystals in the fluid as proof there is no infection
• Inject steroid into a hot joint before infection is excluded
• Leave a septic joint undrained

• Antibiotics before aspiration
• Crystal false reassurance
• No drainage
• Too short a course for S. aureus or prosthetic joints

Ward under joint medical–orthopaedic care; ICU if septic shock. Follow-up of function and ESR/CRP after the course.