Gout is caused by purine metabolic disorder, clinically characterized by hyperuricemia, and the hyperuricemia-induced gouty acute arthritis, tophus sedimentation, tophus chronic arthritis and joint deformity. And it may involve the kidney, resulting in chronic interstitial nephritis and uric-acid nephr-olithiasis. The disease may be primary or secondary. The incidence rises with aging, and it is higher in males than that in females with ratio of 10:1.