Gout is a true crystal deposition disease. It can be defined as the pathological reaction of the joint or periarticular tissues to the presence of monosodium urate monohydrate (MSUM) crystals. MSUM crystals preferentially deposit in peripheral connective tissues in and around synovial joints, initially favouring lower rather than upper limbs and especially targeting the first metatarsophalangeal and small joints of feet and hands.

Typical attacks have the following characteristics:

• extremely rapid onset, reaching maximum severity in just 2-6 hours, often waking the patient in the early morning
• severe pain, often described as the 'worst pain ever'
• extreme tenderness-the patient is unable to wear a sock or to let bedding rest on the joint
• marked swelling with overlying red, shiny skin
• self-limiting over 5-14 days, with complete return to normality