Septic arthritis

Question 1

A 61 year old man presents with an acutely painful left knee. He feel generally unwell and feverish. The knee is swollen, tender and warm. His temperature is 38.8. How would you assess and manage him?

Answer 1

Impression
Septic arthritis given fevers and monoarthritis. Importantly given systemic features want to rule out sepsis so would take A to E approach to initial assessment Would keep broad differentials in considering other causes of mono arthritis including;
- Crystalline: Gout, Pseudogout
- MSK: trauma, soft tissue injury,
- Infective: Oestomyelitis, cellulitis, erysipelas,
- Haemarthrosis

Goals

• Check stability, treat HD unstable emergently
• joint aspirate for definitive diagnosis
• treat with empirical ABx, surg consult for wash-out/debridement

Question 2

Septic arthritis - Assessment

Answer 2

Assessment
- A to E, assessing for HD instability, particularly paying attention to C;

C - IVC access; bloods: VBG, FBC, cultures, UEC, CRP/ESR. begin IV empiric ABx coverage, administer fluids if shocked +/- vasopressor support.

Question 3

Septic arthritis - History

Answer 3

History

• PC: onset, duration, progression, pain (SOCRATES), limited ROM, swelling, erythema, warmth
• Risks: trauma, skin infection, immunocompromised, MRSA colonised,
• PMHx: knee surgeries, joint replacement?
• SNAP

Question 4

Septic arthritis - Examination

Answer 4

Examination

• General appearance + recheck vitals
• Knee exam: erythema, swelling, limited active and passive ROM, tenderness to palpation, warmth, joint effusion
• Systems review: systemic illness

Question 5

Septic arthritis - Investigations

Answer 5

Investigations
- Bedside: Joint aspirate + MCS
o microscopy: crystals for gout, if septic then expecting raised WCC >70%, turbid in colour
- Full septic screen if indicated
- Bloods: As per A to E
- Imaging: X-Ray, MRI if suspicious of osteomyelitis

Question 6

Septic arthritis - Management

Answer 6

Management
- Would discuss with ortho reg on call, likely arrange for surgical wash-out +/- debridement in theatres

Definitive

• Systemic ABx therapy, empirical treatment is IV fluclox if suspicious of gram +ve, IV ceftriaxone if not. Can utilise sepsis empirical treatment too if indicated.
• Drainage with needle aspiration
• Surgical washout +/- debridement
• Joint replacement if appropriate

Supportive

• Analgesia
• Antipyretics
• Immobilisation, hydration
• Fluids
• Early physio referral for rehab