Gout

Gout is a common and treatable disorder of purine metabolism. Gout typically presents as recurrent self-limiting episodes of severe inflammatory arthritis affecting the foot. In the presence of persistent hyperuricaemia, tophi, chronic synovitis, and joint damage may develop. Diagnosis of gout is confirmed by identification of monosodium urate (MSU) crystals using polarizing light microscopy. Hyperuricaemia is the central biochemical cause of gout. Genetic variants in certain renal tubular urate transporters including SLC2A9 and ABCG2, and dietary factors including intake of high-purine meats and seafood, beer, and fructose, contribute to development of hyperuricaemia and gout. Gout treatment includes: (1) management of the acute attack using non-steroidal anti-inflammatory drugs (NSAIDs), corticosteroids, or low-dose colchicine; (2) prophylaxis against gout attacks when commencing urate-lowering therapy (ULT), with NSAIDs or colchicine; and (3) long-term ULT to achieve a target serum urate of less than 0.36 mmol/litre. Interleukin (IL)-1β‎ is a central mediator of acute gouty inflammation and anti-IL-1β‎ therapies show promise for treatment of acute attacks and prophylaxis. The mainstay of ULT remains allopurinol. However, old ULT agents such as probenecid and benzbromarone and newer agents such as febuxostat and pegloticase are also effective, and should be considered in patients in whom allopurinol is ineffective or poorly tolerated. Management of gout should be considered in the context of medical conditions that frequently coexist with gout, including type 2 diabetes, hypertension, dyslipidaemia, and chronic kidney disease. Patient education is essential to ensure that acute gout attacks are promptly and safely managed, and long-term ULT is maintained.