Septic arthritis

Question 1

An 80 year old woman presents with a painful swollen right knee. She has a temperature of 38.2°C. The knee joint is swollen, tender and warm. How would you manage her?

Answer 1

Impression
Given the womans fever and infective joint symptoms (monoarticular), I am most concerned about a septic arthritis, which is a severe joint infection that is a surgical emergency requiring wash out in theatres and antibiotic treatment.

There are several differentials to consider, in particular;

• Crystalline arthropathies (gout, pseudogout attacks)
• Trauma
• MSK injury
• haemarthrosis
• DVT
• less likely to be an inflammatory form of arthritis given single joint affected and acute clinical picture.

Goals
- ensure HD stability and arrange urgent surgical review with a view to definitive management with a joint wash-out and antibiotics

Question 2

Septic arthritis - Assessment

Answer 2

Assessment
- would take A to E to ensure HD stability initially in this patient, focussing on any evidence of sepsis and instituting appropriate emergent management of this.

Question 3

Septic arthritis - History

Answer 3

History

• sx: joint pain, swelling, tenderness, erythema, precipitating injury, recent surgery/trauma, systemic infective sx (fevers, tachy, etc), limited mobility, time-course, previous infections, ?MRSA?
• RISKS: age, immunocompromised, recent surgeries/trauma
• PC: history of joint disease, past surgeries
• PMHx: diabetes, vascular disease, etc
• Medications, allergies, last meal, fam Hx

Question 4

Septic arthritis - Examination

Answer 4

Examination

• general observation + vitals
• Knee exam: swelling, increased temperature, erythema, pain, limited mobility
• neurovascular status of lower limb (ensure peripheral pulses and sensation).

Question 5

Septic arthritis - Investigations

Answer 5

Investigations
Key/diagnostic
- Joint aspirate for MCS (prior to ABx treatment); typically turbid, high WCC, culture positive, differentiate crystalline arthropathies with infection microscopically.

Bedside: Vitals
Bloods: FBC, UEC, LFT, ESR/CRP, Blood cultures, VBG (lactate for sepsis)
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