Gout - Causes

Highlights	Complications	Medications
Introduction	Risk Factors	Lifestyle Changes
Causes	Diagnosis	Resources
Symptoms	Treatment	References

Causes

Gout is classified as either primaryor secondary, depending on what causes the high levels of uric acid in the blood (hyperuricemia). In both types of gout, between 70 - 95% of hyperuricemia cases occur when the body doesn't get rid of (excrete) enoughuric acid, rather than uric acid over-production.

Many people develop hyperuricemia,but not all people with the condition develop gout. Researchers have not yet determined the reason for this, or why gout develops in certain joints but not in others.

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Primary Gout

More than 99% of primary gout cases are referred to as idiopathic, meaning that the cause of the hyperuricemia cannot be determined. They are most likely due to a combination of hormonal and genetic factors that cause metabolic abnormalities resulting in overproduction of uric acid or reduced excretion of uric acid. Consumption of certain purine-rich foods and certain alcoholic beverages may also contribute to primary gout. The remaining 1% of primary gout cases are traceable to either of two rare inherited enzyme defects that affect purine synthesis in the cells. One in five people with gout has a family history of the disease.

Secondary Gout

In secondary gout, hyperuricemia is caused by drug therapy or by medical conditions other than an inborn metabolic disorder that increase uric acid concentration.

Alcohol Use. Alcohol use, especially beer consumption, is a major contributor to gout and increases uric acid levels in three ways:

By providing an additional dietary source of purines (the compounds from which uric acid is formed)
By intensifying the body?s production of uric acid
By interfering with the kidneys? ability to excrete uric acid

Renal (Kidney) Insufficiency and Its Causes. Hyperuricemia occurs in30 - 85% of people who have renal(kidney) insufficiency. Renal insufficiency is a major cause of gout in older people. This results in an impaired ability of the kidneys to eliminate waste products, including uric acid, which then build up in the blood. This condition, in turn, can be the result of the following:

The kidneys are responsible for removing waste from the body, regulating electrolyte balance and blood pressure, and the stimulation of red blood cell production.

Thiazide diuretics (the ?water pills? used to control hypertension). These agents are very highly associated with gout. In fact, 75% of elderly-onset gout patients report the use of diuretics.
Organ transplantation. Kidney transplantation poses a high risk for renal insufficiency and gout. In addition, other transplantation procedures, such as heart and liver, increase the risk. The procedure itself poses a risk. In addition, cyclosporine an immunosuppressive agents used after these procedures to help prevent rejection of the implant, poses a particular risk for gout. It also interacts with indomethacin, a common gout treatment. (Alternative agents, such as tacrolimus, may be effective and pose less of a risk of gout.)