ACUTE HOT JOINT, SEPTIC ARTHRITIS AND GOUT

Symptoms and signs

• Acutely painful, swollen joint
• Warm, tender, swollen joint (+/- effusion)

Alert

• Assume patients with a short history of a hot, swollen, tender joint with restricted range of movement have septic arthritis even in the absence of a fever until proven otherwise
• Pyrexia may not be a feature of septic arthritis, especially in the elderly or Immunocompromised, or in patients with diabetes, renal failure or rheumatoid arthritis
• In patients with prosthetic joint and pyrexia of unknown origin (PUO) – consider prosthesis infection
• If patient has acute arthritis affecting more than one joint, discuss case with on-call rheumatologist

Investigations

Immediate

• Urgent joint aspiration – see Knee aspiration guideline
• contact on-call orthopaedic team (bleep) for urgent joint aspiration +/- arthroscopic washout and further management. If prosthetic joint, orthopaedic team aspirate in theatre
• Synovial fluid
• polarised microscopy
• Gram stain and culture of synovial fluid
• FBC, U&E
• Blood cultures – see Collection of blood culture specimens guideline
• Swab from any infected skin lesion
• Urine dipstick. If positive for nitrites and/or leucocytes, MSU
• If gonococci suspected, swab rectum, urethra and throat, and contact genitourinary medicine

Within 24 hr

• ESR
• CRP
• Serum uric acid
• X-ray of affected joint

Differential diagnosis

• Septic arthritis
• Crystal arthritis, including gout
• Acute inflammatory arthritis (e.g. reactive arthritis or rheumatoid arthritis)
• Haemarthrosis

• For medical inpatients, contact on-call rheumatology team

Supportive

• Adequate analgesia for joint pain: naproxen 500 mg single oral dose, then 250 mg oral 6-hrly (if not contraindicated) plus:
• step 1: paracetamol 1 g oral 6-hrly
• step 2: if paracetamol alone not adequate, add codeine phosphate 30–60 mg oral 6-hrly
• step 3: if codeine phosphate not adequate, substitute morphine sulphate solution 10 mg oral 4-hrly

• Refer to physiotherapists for ice pack and splint on joint
• Rehydrate – see Adult fluid management guideline
• If patient already taking low-dose corticosteroids, consider increasing to prednisolone 10 mg oral daily

Antimicrobial therapy

• Start as soon as joint aspirated.
• Most common microbe causing septic arthritis is Staphylococcus spp (including MRSA), other causes include Steptococcus spp and Gram-negative bacilli
• If patient Immunocompromised or has prosthesis, contact consultant in infectious diseases or consultant microbiologist for advice
• If severe sepsis present, refer to Sepsis management guideline and treat with appropriate IV antimicrobials

Penicillin Allergy

• True penicillin allergy is rare
• Ask the patient and record what happened when they were given penicillin
• If any doubt about whether patient is truly allergic to penicillin, seek advice from a microbiologist or consultant in infectious diseases

Infection Control alerts

• Check for IC alert.
• If IC alert not available, check previous 12 months of microbiology reports
• If MRSA present, treat as tagged for MRSA. See MRSA management
• If ESBL, MGNB, CARB present, treat as tagged for ESBL. See ESBL/MGNB/CARB management

• Pulse, BP, temperature 4-hrly until patient stable
• While effusion persists, repeat culture of joint effusion daily
• WBC, ESR, CRP, U&E every 48 hr
• If using sodium fusidate or rifampicin, liver function tests weekly

Septic arthritis

• Supportive treatment, as above

• Refer to physiotherapists for passive exercise and rehabilitation
• Perform regular aspiration of the joint to dryness +/- arthroscopic lavage while a significant effusion persists
• If patient able to be managed at home and on IV antimicrobials, refer to outpatient antibiotic therapy service for IV antimicrobials at home

Review antimicrobial choice after Gram stain result

• If gonococci isolated and strain sensitive:
• refer patient to genitourinary medicine
• ceftriaxone 1 g IV or IM daily or if anaphylaxis to penicillin, ciprofloxacin 500 mg oral 12-hrly for 7 days
• if strain resistant to ciprofloxacin, contact consultant microbiologist
• If no bacteria isolated, consider stopping antimicrobials but note that neither the absence of organisms on Gram stain nor a negative subsequent synovial fluid culture excludes the diagnosis of septic arthritis. Discuss with rheumatology team

Failure to respond to therapy

• Reconsider diagnosis
• Repeat cultures
• If no response within 48 hr, contact rheumatology team

Duration of antimicrobial therapy

• Do not stop treatment until symptoms (e.g. fever) and signs (e.g. joint effusion) resolve, and WBC and CRP return to normal
• If infection likely or proven, continue IV antimicrobials for at least 2 weeks.
• If good clinical response to IV therapy, CRP falling and good information on organism and its sensitivities after that time, switch to oral therapy
• contact consultant microbiologist if required
• Continue antimicrobials for a 4–6 weeks total. Do not stop treatment until symptoms (e.g. fever) and signs (e.g. joint effusion) resolve, and WBC and CRP return to normal

Confirmed gout

• Gout is confirmed by microscopic identification of urate (negatively birefringent) crystals in synovial fluid
• Rehydrate – see Adult fluid management guideline
• Consider stopping diuretics
• If no contraindications, start NSAID (e.g. naproxen 750 mg single dose then 250 mg oral 8-hrly) at maximum dose or colchicine in doses of 500 microgram 2–4 times daily (max 6 mg per course).
• choice of first-line agent will depend on patient preference, renal function and co-morbidities.
• prescribe any patients on NSAIDs or cyclooxygenase-2 inhibitors (coxibs) a gastro-protective agent
• Intra-articular and systemic corticosteroids are effective in acute gout but use only under rheumatologist guidance
• In difficult or resistant cases, contact rheumatology team

• If patient already under follow-up because of arthritis, review existing follow-up arrangements
• Refer new cases to a consultant rheumatologist