Gout is a form of arthritis caused by the deposition of uric acid crystals in joints, most often, in the joint of the big toe. To remove excess uric acid from the blood, urate crystals are deposited in the joints where they cause chemical irritation, with intense pain, swelling, and often a fever. These crystals may also be deposited in large nodules near the joints, and may form stones in the urinary tract.
In some cases, the cause of gout is unknown, and blood uric acid levels are normal. Most patients, however, have high blood uric acid levels, which may be due to underlying problems such as:
• Inherited enzyme defects
• Diseases such as lymphoma
• Anything causing a sudden rise in uric acid in the blood e.g.
o dietary excess – especially red meat
o excess alcohol consumption – beer and spirits
o some drugs – e.g. certain diuretics
o trauma or previous degeneration in the joint
Microscopic analysis of a sample of joint fluid can show the typical crystals and confirm the diagnosis of gout in doubtful cases. Colchicine, NSAIDs and steroids are the main treatments for acute attacks.
Gout typically causes no symptoms at all between acute attacks. Over time, however, bones may be destroyed near joints, and urate crystals may be deposited in other tissues, forming the painless nodules (tophi) often seen e.g. on earlobes, elbows and hands. Chronic gout may also lead to kidney stones formed from these urate crystals.