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Source: Ernst ME, Clark EC. Gout and Hyperuricemia. In: DiPiro JT, Talbert RL, Yee GC, Matzke GR, Wells BG, Posey LM, eds. Pharmacotherapy: A Pathophysiologic Approach. 8th ed. Accessed May 27, 2012.

  • Acute gout

  • Recurrent painful attacks of acute arthritis with hyperuricemia and monosodium urate crystals in synovial fluid leukocytes.

  • Excess accumulation of uric acid in gout from overproduction or underexcretion of uric acid.
  • Overproducers excrete >600 mg/day of uric acid after purine-free diet for 3–5 days. Underexcretors are hyperuricemic individuals who excrete <600 mg/day of uric acid.
  • Agents that may decrease renal uric acid clearance:
    • Thiazide and loop diuretics
    • Nicotinic acid
    • Salicylates (<2 g/day)
    • Ethanol
    • Pyrazinamide
    • Levodopa
    • Ethambutol
    • Cyclosporine
    • Cytotoxic drugs

  • Uric acid is waste product from purine degradation.
  • Deposition of urate crystals in synovial fluid initiates inflammatory process. Phagocytosis of urate crystals by leukocytes causes lysis of cells and discharge of proteolytic enzymes, resulting in intense joint pain, erythema, warmth, and swelling.
  • Uric acid nephrolithiasis occurs in 10–25% of patients with gout.
    • Risk factors:
      • Excessive urinary excretion of uric acid
      • Acidic urine
      • Concentrated urine
  • In uric acid nephropathy, acute renal failure occurs from blockage of urine flow secondary to massive precipitation of uric acid crystals in collecting ducts and ureters.
  • Tophi may occur in longstanding hyperuricemia and may involve:
    • Great toe
    • Helix of ear
    • Olecranon bursae
    • Achilles tendon
    • Knees
    • Wrists
    • Hands

  • Affects men 7–9 times more often than women.
  • Incidence increases with age, peaking at age 30–50 years.
  • Annual incidence ranges from 1 in 1000 for men ages 40–44 years and 1.8 in 1000 for those ages 55–64 years.
  • Lowest rates in young women, approximately 0.8 cases per 10,000 patient-years.

Signs and Symptoms

  • Rapid onset of excruciating localized joint pain, swelling, erythema, and warmth.
  • Attacks are typically monoarticular, most often first metatarsophalangeal joint (podagra), but also insteps, ankles, heels, knees, wrists, fingers, and elbows.
  • Fever and leukocytosis common.
  • Untreated attacks last from 3–14 days before spontaneous recovery.

Means of Confirmation and Diagnosis

  • Presumptive diagnosis based on presence of characteristic signs and symptoms and the response to treatment.

Laboratory Tests

  • Elevated serum uric acid concentration, but acute gout can occur with normal levels.
  • Leukocytosis


  • X-rays may show asymmetric swelling within joint or subcortical cysts without erosions.

Diagnostic Procedures

  • Definitive diagnosis requires aspiration of synovial fluid from affected joint and identification of intracellular crystals of monosodium urate monohydrate within leukocytes.

Differential Diagnosis

  • Terminate acute attack.
  • Prevent recurrent attacks.
  • Prevent complications from chronic urate crystal deposition in tissues.

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