Hyperuricemia

Excerpt

Hyperuricemia is defined as an elevated serum uric acid level, usually greater than 6 mg/dL in women and 7 mg/dL in men. Elevated serum uric acid is present in an estimated 38 million Americans, and the incidence is increasing worldwide as developing countries adopt more Western diets and lifestyles. Most people with this condition will not have obvious clinical manifestations, however, it is unclear what the long-term effects of hyperuricemia are on overall cardiovascular health, renal function, and overall morbidity. Hyperuricemia results from increased uric acid production, decreased excretion, or a combination of both processes.

Dietary purines are responsible for about one-third of the body's daily serum uric acid production; the rest is synthesized from endogenous sources. Elevated uric acid can also be seen with accelerated purine degradation in high cell turnover states (eg, hemolysis, rhabdomyolysis, tumor lysis) and decreased excretion (eg, genetic disorders, renal insufficiency, metabolic syndrome). About two-thirds of uric acid is excreted through the kidney and one-third through the gastrointestinal (GI) tract. However, these proportions can change depending on medications or dysfunction in the renal or GI systems.

Most people with hyperuricemia are asymptomatic (85% to 90%), but elevated uric acid levels in the blood or urine can lead to gout or nephrolithiasis. Hyperuricemia and hyperuricosuria have also been linked with other disorders such as metabolic syndrome, diabetes mellitus, cardiovascular disease, hypertension, atherosclerosis, obesity, and chronic renal disease.