Acute gout and pseudogout

Gout and pseudogout are the two most common crystal arthropathies. Gout is caused by deposition of monosodium urate monohydrate crystals, and pseudogout by calcium pyrophosphate crystals. This chapter commences with a summary of their epidemiologies. Gout predominantly occurs in males and post-menopausal women between 30-60 years of age. Risk factors include conditions which promote hyperuricaemia, due to overproduction or under-excretion of urate. Pseudogout occurs around 60 years of age and, the risk increases in the elderly. The risk factors include conditions that promote altered concentrations of calcium, inorganic pyrophosphate (PPi) and the solubility products of these ions. In gout, attacks begin abruptly, usually overnight, and typically reach maximum intensity within 12 hours. Trauma may cause agitation, with subsequent deposition of urate and calcium pyrophosphate dihydrate deposition (CPPD) crystals in patients with tophi and chondrocalcinosis, respectively. Finally, the chapter lists the urgent investigation required for suspected acute gout or pseudogout.