Hyperuricosuria is a medical term referring to the presence of excessive amounts of uric acid in the urine. For men this is at a rate greater than 800 mg/day, and for women, 750 mg/day. Notable direct causes of hyperuricosuria are dissolution of uric acid crystals in the kidneys or urinary bladder, and hyperuricemia. Notable indirect causes include uricosuric drugs, rapid breakdown of bodily tissues containing large quantities of DNA and RNA, and a diet high in purine.Acute hyperuricosuria is a common complication of tumor lysis syndrome. This syndrome appears not to contribute to gout and to uric acid nephrolithiasis, which is evidence that these two conditions have chronic, not acute, causes.If neither hyperuricemia nor gout is present, then the risk of uric acid nephrolithiasis can be reduced by the use of antiuricosuric drugs. One should also consider eating a low purine diet. Additionally, making the urine pH more alkaline is protective.