Gout - Introduction

Without treatment, tophi develop on average about 10 years after the initial onset of gout, although their first appearance can range from three to 42 years. They are more apt to appear early in the course of the disease in older people. In the elderly population, women appear to be at higher risk for tophi than men.

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Today, drug therapy has reduced the prevalence of chronic tophaceous gout to as little as 3% of patients. Certain groups, such as transplant patients receiving cyclosporine, however, still face a high risk of developing tophi.

Uric Acid Nephrolithiasis (Kidney Stones). Uric acid nephrolithiasis occurs when kidney stones form from uric acid. In one study, patients with these stones were more likely to have elevated levels of uric acid in their blood than in their urine, suggesting that gout is responsible for these stones. Uric acid and other kidney stones are present in 10 - 25% of patients with primary gout, a prevalence more than 1,000 times that of the general population. In gout caused by other conditions (called secondary gout), the reported incidence reaches 42%.

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Uric acid stones can also form in the absence of gout or hyperuricemia. Also, not all of the kidney stones in patients with gout are composed of uric acid; some are composed of calcium oxalate, calcium phosphate, or those substances combined with uric acid.

Chronic Uric Acid Interstitial Nephropathy. Chronic uric acid interstitial nephropathy occurs when crystals slowly form in the structures and tubes that carry fluid from the kidney. It is reversible and not likely to injure the kidneys.

Kidney Failure. Sudden overproduction of uric acid can occasionally block the kidneys and cause them to fail. This occurrence is very uncommon but can occur with the following conditions: