EM Notes – Gout

Arthritis due to deposition of monosodium urate monohydrate crystals in previously normal tissues causing acute inflammation and eventual tissue damage. The four types of gout are:

Asymptomatic, hyperuricaemia, acute gout, and intercritical gout & chronic tophaceous gout.

Classification

The condition can be classified into 1˚ or 2˚ gout depending on the cause of hyperuricaemia:

  1. Primary gout occurs mainly in men age 30-60 years presenting with acute attacks.
  2. Secondary gout normally due to chronic diuretic Rx. Older M & F, assoc with OA.

Pathogenesis

It affects both upper and lower limbs with acute attacks. Less often it presents with painful, tophaceous deposits (± discharge) in Heberden’s and Bouchard’s nodes.

  1. Most pts with hyperuricaemia never → gout and gouty pts may be normouricaemic.
  2. Patients can be over-excreters of uric acid, normo-excreters or under-excreters.
  3. Most cases of primary gout are due to undersecretion. <10% due to overproduction.

Epidemiology

  1. Fairly common.
  2. 9M:1F

Risk factors

  1. Male sex
  2. Meat & seafood
  3. Alcohol (>10g/d)
  4. Diuretics
  5. Obesity
  6. Hypertension
  7. IHD
  8. Diabetes mellitus
  9. CRF
  10. High triglycerides
  11. Malignancy

Presentation

  1. Acutely inflamed joint typically over 6-24hr period
  2. 50% of all attacks & 70% 1st attacks affect 1st MTPJ (“podagra”).
  3. Other sites often affected are: Knee, midtarsal joints, wrists, ankles, small hand joints, elbows
  4. Chronic tophaceous gout – large irregular firm white-yellow nodules mainly around extensor surfaces of fingers, hands, forearms, elbows, achilles tendons and ear.

Investigations

Urine: 24hr renal uric acid secretion

Blood: FBC, uric acid (poor sensitivity & specificity), CMP, BSL, lipids

Joint aspirate: Gram stain, WCC, microscopy – monosodium urate (MSU) crystals (negatively birefringent) or tophi for gout.

Imaging: chronic gout – punched out lesions, sclerosis and tophi may be seen.

Management

Supportive: Ice pack, rest, regular paracetamol±codeine,

Manage risk factors: ↓hyperuricaemic drugs (thiazides and loop diuretics, low dose aspirin < 1g/day, pyrazinamide, ethambutol, nicotinic acid, ciclosporin), lose wt, ↓meat/seafood, ↓EtOH, treat HT/renal impairment/hyperlipidaemia/vascular disease.

Anti-inflammatories:

  1. NSAIDs – Avoid aspirin (continue if on IHD antiplatelet dose). Indomethacin or diclofenac 50mg tds. Risk of GIT SE esp if high EtOH intake. OR
  2. Colchicine – 0.5mg/hr until better, max 6mg (3mg if renal/liver disease), or diarrhoea.
  3. Steroids – 2nd line. Prednisolone 10mg bd x 5d, then taper over 2wks. Injs may help.

Uricosuric drugs:

  1. Probenecid, losartan.

Prophylaxis: If regular attacks. Delay until 2-3wks after acute attack resolves.

  1. Co-prescribe colchicine or NSAID to prevent gout whilst initiating Rx
  2. Allopurinol 300mg OD – 1st choice esp if impaired renal function or calculi present.
  3. Sulfinpyrazone – alternative to allopurinol or as adjunct in resistant cases. CI: if RF
  4. Colchicine – 0.5mg bd
  5. Low dose corticosteroids and NSAIDs have also been used

Complications

  1. Recurrent painful episodes
  2. Renal disease: calculi (10-25%, urate or oxalate), chronic urate nephropathy.
  3. Severe degenerative arthritis
  4. Secondary infections
  5. Carpal tunnel syndrome (rare)
  6. Nerve or spinal cord impingement
VN:F [1.9.22_1171]
Rate this post
Rating: 5.0/5 (1 vote cast)
EM Notes - Gout, 5.0 out of 5 based on 1 rating