This booklet contains general information about gout. It describes what gout is and how it develops. It also explains how gout is diagnosed and treated. At the end is a list of key words to help you understand the terms used in this booklet. If you have further questions after reading this booklet, you may wish to discuss them with your doctor.
What Is Gout?
Gout is a painful condition that occurs when the bodily waste product uric acid is deposited as needle-like crystals in the joints and/or soft tissues. In the joints, these uric acid crystals cause inflammatory arthritis, which in turn leads to intermittent swelling, redness, heat, pain, and stiffness in the joints.
In many people, gout initially affects the joints of the big toe (a condition called podagra). But many other joints and areas around the joints can be affected in addition to or instead of the big toe. These include the insteps, ankles, heels, knees, wrists, fingers, and elbows. Chalky deposits of uric acid, also known as tophi, can appear as lumps under the skin that surrounds the joints and covers the rim of the ear. Uric acid crystals can also collect in the kidneys and cause kidney stones.
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What Is Uric Acid?
Uric acid is a substance that results from the breakdown of purines. A normal part of all human tissue, purines are found in many foods. Normally, uric acid is dissolved in the blood and passed through the kidneys into the urine, where it is eliminated.
If there is an increase in the production of uric acid or if the kidneys do not eliminate enough uric acid from the body, levels of it build up in the blood (a condition called hyperuricemia). Hyperuricemia also may result when a person eats too many high-purine foods, such as liver, dried beans and peas, anchovies, and gravies. Hyperuricemia is not a disease, and by itself it is not dangerous. However, if excess uric acid crystals form as a result of hyperuricemia, gout can develop. The crystals form and accumulate in the joint, causing inflammation.
What Are the Four Stages of Gout?
Gout can progress through four stages:
- Asymptomatic (without symptoms) hyperuricemia. In this stage, a person has elevated levels of uric acid in the blood (hyperuricemia), but no other symptoms. Treatment is usually not required.
- Acute gout, or acute gouty arthritis. In this stage, hyperuricemia has caused the deposit of uric acid crystals in joint spaces. This leads to a sudden onset of intense pain and swelling in the joints, which also may be warm and very tender. An acute attack commonly occurs at night and can be triggered by stressful events, alcohol or drugs, or the presence of another illness. Attacks usually subside within 3 to 10 days, even without treatment, and the next attack may not occur for months or even years. Over time, however, attacks can last longer and occur more frequently.
- Interval or intercritical gout. This is the period between acute attacks. In this stage, a person does not have any symptoms.
- Chronic tophaceous gout. This is the most disabling stage of gout. It usually develops over a long period, such as 10 years. In this stage, the disease may have caused permanent damage to the affected joints and sometimes to the kidneys. With proper treatment, most people with gout do not progress to this advanced stage.
When It’s Not Gout, It May Be Pseudogout
Gout is sometimes confused with other forms of arthritis because the symptoms—acute and episodic attacks of joint warmth, pain, swelling, and stiffness—can be similar. One form of arthritis often confused with gout is called pseudogout. The pain, swelling, and redness of pseudogout can also come on suddenly and may be severe, closely resembling the symptoms of gout. However, the crystals that irritate the joint are calcium phosphate crystals, not uric acid. Therefore, pseudogout is treated somewhat differently and is not reviewed in this booklet.
What Causes Gout?
A number of risk factors are associated with hyperuricemia and gout. They include:
Who Is Likely to Develop Gout?
Scientists estimate that 6 million adults age 20 and older report having had gout at some time in their lives.1 It is rare in children and young adults. Men, particularly those between the ages of 40 and 50, are more likely to develop gout than women, who rarely develop the disorder before menopause. People who have had an organ transplant are more susceptible to gout.
1According to the National Arthritis Data Workgroup, this estimate is based on self-reports, which may produce an overestimation of prevalence, as cited in Helmick CG, Felson DT, Lawrence RC, Gabriel S, Hirsch R, Kwoh CK, et al.; National Arthritis Data Workgroup. Estimates of the prevalence of arthritis and other rheumatic conditions in the United States. Part 1. Arthritis and Rheumatism 2008;1:15-25.
How Is Gout Diagnosed?
Gout may be difficult for doctors to diagnose because the symptoms can be vague, and gout often mimics other conditions. Although most people with gout have hyperuricemia at some time during the course of their disease, it may not be present during an acute attack. In addition, having hyperuricemia alone does not mean that a person will get gout. In fact, most people with hyperuricemia do not develop the disease.
To confirm a diagnosis of gout, a doctor may insert a needle into an inflamed joint and draw a sample of synovial fluid, the substance that lubricates a joint. The joint fluid is placed on a slide and examined under a microscope for uric acid crystals. Their absence, however, does not completely rule out the diagnosis.
The doctor also may find it helpful to look for uric acid crystals around joints to diagnose gout. Gout attacks may mimic joint infections, and a doctor who suspects a joint infection (rather than gout) may also culture the joint fluid to see whether bacteria are present.
How Is Gout Treated?
With proper treatment, most people who have gout are able to control their symptoms and live productive lives. Gout can be treated with one or a combination of therapies. The goals of treatment are to ease the pain associated with acute attacks, to prevent future attacks, and to avoid the formation of tophi and kidney stones. Successful treatment can reduce discomfort caused by the symptoms of gout, as well as long-term damage to the affected joints. Treatment will help to prevent disability due to gout.
The most common treatments for an acute attack of gout are nonsteroidal anti-inflammatory drugs (NSAIDs)2 taken orally (by mouth), or corticosteroids, which are taken orally or injected into the affected joint. NSAIDs reduce the inflammation caused by deposits of uric acid crystals, but have no effect on the amount of uric acid in the body.
2Warning: NSAIDs can cause stomach irritation or, less often, they can affect kidney function. The longer a person uses NSAIDs, the more likely he or she is to have side effects, ranging from mild to serious. Many other drugs cannot be taken when a patient is being treated with NSAIDs because NSAIDs alter the way the body uses or eliminates these other drugs. Check with your health care provider or pharmacist before you take NSAIDs. Also, NSAIDs sometimes are associated with serious gastrointestinal problems, including ulcers, bleeding, and perforation of the stomach or intestine. People age 65 and older and those with any history of ulcers or gastrointestinal bleeding should use NSAIDs with caution.
Corticosteroids are strong anti-inflammatory hormones. The most commonly prescribed corticosteroid is prednisone. Patients often begin to improve within a few hours of treatment with a corticosteroid, and the attack usually goes away completely within a week or so.
When NSAIDs or corticosteroids do not control symptoms, the doctor may consider using colchicine. This drug is most effective when taken within the first 12 hours of an acute attack.
For some patients, the doctor may prescribe either NSAIDs or oral colchicine in small daily doses to prevent future attacks. The doctor also may consider prescribing other medicines to treat hyperuricemia and reduce the frequency of sudden attacks and the development of tophi.
People who have other medical problems, such as high blood pressure or high blood triglycerides (fats), may find that the drugs they take for those conditions can also be useful for gout.
The doctor may also recommend losing weight, for those who are overweight; limiting alcohol consumption; and avoiding or limiting high-purine foods, which can increase uric acid levels.
What Can People With Gout Do to Stay Healthy?
Fortunately, gout can be controlled. People with gout can decrease the severity of attacks and reduce their risk of future attacks by taking their medications as prescribed. Acute gout is best controlled if medications are taken at the first sign of pain or inflammation. Other steps you can take to stay healthy and minimize gout’s effect on your life include the following:
Research Highlights
Because uric acid’s role in gout is well understood and medications to ease attacks and reduce the risk or severity of future attacks are widely available, gout is one of the most—if not the most—controllable forms of arthritis. But researchers continue to make advances that help people live with gout. Perhaps someday these advances will prevent this extremely painful disease.
Some areas of gout research include the following:
More information on research is available from the following resources:
Where Can People Find More Information About Gout?
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Information Clearinghouse
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
Phone: 301-495-4484
Toll Free: 877-22-NIAMS (877-226-4267)
TTY: 301-565-2966
Fax: 301-718-6366
Email: NIAMSinfo@mail.nih.gov
Website: http://www.niams.nih.gov
Bethesda, MD 20892-3675
Phone: 301-495-4484
Toll Free: 877-22-NIAMS (877-226-4267)
TTY: 301-565-2966
Fax: 301-718-6366
Email: NIAMSinfo@mail.nih.gov
Website: http://www.niams.nih.gov
Other Resources
American College of Rheumatology
Website: http://www.rheumatology.org
Arthritis Foundation
Website: http://www.arthritis.org
Key Words
Corticosteroids. Powerful anti-inflammatory hormones made naturally in the body or man-made for use as medicine. Injections of corticosteroid drugs are sometimes used to treat inflammation in the shoulder, knee, and other joints.
Diuretics. A type of medication that promotes the formation and output of urine. Diuretics are prescribed to treat the accumulation of excess fluid in bodily tissues that can result from diseases of the kidneys, liver, lungs, or heart. They may also be used to treat high blood pressure or glaucoma, a condition in which pressure builds up inside the eye.
Hemolytic anemia. A form of anemia (deficiency of red blood cells) caused by the destruction of the cells rather than the body’s inability to produce them in adequate numbers.
Hyperuricemia. The presence of elevated levels of uric acid in the blood.
Hypothyroidism. A condition in which the thyroid gland (the gland that makes and stores hormones that regulate heart rate, blood pressure, body temperature, and the rate at which food is converted to energy) is underactive. Without treatment, this condition can result in fatigue, weight gain, other serious medical problems, and even death.
NSAIDs. A class of medications, available over the counter or with a prescription, that ease pain and inflammation.
Podagra. Gout in the big toe.
Pseudogout. A condition often mistaken for gout that results from the deposit of calcium phosphate crystals (not uric acid crystals as in gout) in the joints and other tissues. This condition is also called chondrocalcinosis.
Psoriasis. An autoimmune disease characterized by a red scaly rash that is often located over the surfaces of the elbows, knees, and scalp, and around or in the ears, navel, genitals, or buttocks. Approximately 10 to 15 percent of people with psoriasis develop an associated arthritis referred to as psoriatic arthritis.
Purines. Found in the DNA and RNA within the nuclei of cells, purines are part of all human tissue and are found in many foods, especially those high in protein.
Synovial fluid. The slippery fluid produced by the synovium (joint lining) to lubricate the joints.
Tophi. Nodular masses of uric acid crystals that sometimes form in the soft tissue of people with chronic gout. Although tophi are most common around the fingers, elbows, and big toe, they can occur in virtually any part of the body. (The singular is tophus.)
Uric acid. A substance that results from the breakdown of purines, which are part of all human tissue and are found in many foods.
Acknowledgments
The NIAMS gratefully acknowledges the assistance of the following individuals in the preparation and review of the original version of this booklet: Barbara Mittleman, M.D., and Bernadette Tyree, Ph.D., NIAMS, NIH; John H. Klippel, M.D., Arthritis Foundation, Atlanta; Roland W. Moskowitz, M.D., University Hospitals of Cleveland; and Lawrence Ryan, M.D., Medical College of Wisconsin in Milwaukee.
The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services’ National Institutes of Health (NIH), is to support research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. The National Institute of Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse is a public service sponsored by the NIAMS that provides health information and information sources. Additional information can be found on the NIAMS Website at www.niams.nih.gov.
