Characteristics

• Occurs in approximately 1% of the population; male:female ratio of 20:1.

• Characterised by a pathological reaction to monosodium urate monohydrate crystals by the joint or periarticular tissues.

• Increases with age and serum uric acid levels, although only a fraction of patients with hyperuricaemia will develop gout.

• Primary gout – overproduction or under-secretion of uric acid. More frequently seen in men and is the commonest cause of inflammatory arthritis in men over 40 years of age.

• Secondary gout – Acquired conditions lead either to over-production (myeloproliferative disorders) or under-excretion of uric acid (renal failure). Drugs such as aspirin and diuretics can precipitate acute attacks.

Clinical features

• Characterised by severe pain, classically waking the patient from sleep.

• The joint is swollen and very sensitive to contact (patient may not even tolerate wearing a sock).

• Typically affects a single distal joint, with the first MTP joint affected in > 50% of cases.

• Other affected joints include the ankle, knee, midfoot, small joints of the hand, wrist and the elbow. Gouty tophi tend to be a late sign.

• Fever, malaise and confusion can occur, particularly in the elderly, and if a large joint is affected.

• May be difficult to differentiate from sepsis; however, the onset of gout is typically hyperacute.

• Although polyarticular attacks are rare, acute attacks may be followed by involvement of other joints. This is thought to be secondary to an acute-phase response.

• Attacks tend to become more frequent and involve multiple sites over time.

• Diagnosis is confirmed by the presence of negatively birefringent crystals in synovial fluid.

Radiological features

• Radiological features usually not seen until 6–12 years after initial attack.

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