Clinical aspects of monosodium urate monohydrate crystal deposition disease (gout).

Gout is a clinical syndrome with a limited range of manifestations arising as a result of the deposition of crystals of monosodium urate, the final product of purine metabolism in humans. Hyperuricemia is a common chemical aberration that is most often mild and remains asymptomatic. Thus, hyperuricemia should be distinguished from gout, even though urate supersaturation is necessary for the expression of gout. Uric acid overproduction and diminished renal uric acid excretion are the major mechanisms resulting in hyperuricemia, and an understanding of the basis of hyperuricemia in individual gout patients is an important step in determining appropriate treatment and in identifying underlying disorders, offending drugs and toxins, and inherited enzyme defects, all of which can result in hyperuricemia and gout. A scheme is presented for the evaluation of patients with new-onset gout, along with a discussion of the relationships between gout/hyperuricemia and a variety of metabolic disorders that are unusually prevalent in gouty populations.