Questions and Answers About
Gout
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. If you have further questions after
reading this booklet, you may wish to discuss them with your doctor.
What Is Gout?
Gout is one of the most
painful rheumatic diseases. It results from deposits of needle-like crystals of
uric acid in connective tissue, in the joint space between two bones, or in
both. These deposits lead to inflammatory arthritis, which causes swelling,
redness, heat, pain, and stiffness in the joints. The term arthritis
refers to more than 100 different rheumatic diseases that affect the joints,
muscles, and bones, as well as other tissues and structures. Gout accounts for
approximately 5 percent of all cases of arthritis.
Pseudogout is sometimes
confused with gout because it produces similar symptoms of inflammation.
However, in this condition, also called chondrocalcinosis, deposits are made up
of calcium phosphate crystals, not uric acid. Therefore, pseudogout is treated
somewhat differently and is not reviewed in this booklet.
Uric acid is a substance that
results from the breakdown of purines, which are part of all human tissue and
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 the body
increases its 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 is not dangerous. However, if
excess uric acid crystals form as a result of hyperuricemia, gout can develop.
The excess crystals build up in the joint spaces, causing inflammation.
Deposits of uric acid, called tophi (singular: tophus), can appear as lumps
under the skin around the joints and at the rim of the ear. In addition, uric
acid crystals can collect in the kidneys and cause kidney stones.
For many people, gout
initially affects the joints in the big toe. Sometime during the course of the
disease, gout will affect the big toe in about 75 percent of patients. It also
can affect the instep, ankles, heels, knees, wrists, fingers, and elbows. The
disease can progress through four stages:
- Asymptomatic (without symptoms)
hyperuricemia--In this stage, a person has elevated levels of uric acid in
the blood but no other symptoms. A person in this stage does not usually
require treatment.
- 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. Early 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 and has normal joint function.
- Chronic tophaceous gout--This is
the most disabling stage of gout and usually develops over a long period, such
as 10 years. In this stage, the disease has 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.
What Causes Gout?
A number of risk factors are
related to the development of hyperuricemia and gout:
- Genetics may play a role in determining
a person's risk, since up to 18 percent of people with gout have a family
history of the disease.
- Gender and age are related to the risk
of developing gout; it is more common in women and adults than in
children.
- Being overweight increases the risk of
developing hyperuricemia and gout because there is more tissue available for
turnover or breakdown, which leads to excess uric acid production.
- Drinking too much alcohol can lead to
hyperuricemia because it interferes with the removal of uric acid from the
body.
- Eating too many foods rich in purines
can cause or aggravate gout in some people.
- An enzyme defect that interferes with
the way the body breaks down purines causes gout in a small number of people,
many of whom have a family history of gout.
- Exposure to lead in the environment can
cause gout.
Some people who take certain
medicines or have certain conditions are at risk for having high levels of uric
acid in their body fluids. For example, the following types of medicines can
lead to hyperuricemia because they reduce the body's ability to remove uric
acid:
- Diuretics, which are taken to eliminate
excess fluid from the body in conditions like hypertension, edema, and heart
disease, and which decrease the amount of uric acid passed in the
urine;
- Salicylates, or anti-inflammatory
medicines made from salicylic acid, such as aspirin;
- The vitamin niacin, also called
nicotinic acid;
- Cyclosporine, a medicine used to
suppress the body's immune system (the system that protects the body from
infection and disease) and control the body's rejection of transplanted organs;
and
- Levodopa, a medicine used to support
communication along nerve pathways in the treatment of Parkinson's
disease.
Who Is
Likely To Develop Gout?
Gout occurs in approximately
840 out of every 100,000 people. It is rare in children and young adults. Adult
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.
How Is Gout Diagnosed?
Gout may be difficult for
doctors to diagnose because the symptoms may be vague, and they often mimic
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. A laboratory technician
places some of the fluid on a slide and looks for monosodium urate crystals
under a microscope. Their absence, however, does not completely rule out the
diagnosis. The doctor also may find it helpful to examine chalky, sodium urate
deposits (tophi) around joints to diagnose gout. Gout attacks may mimic joint
infections, and a doctor who suspects a joint infection (rather than gout) may
check for the presence of bacteria.
Signs and Symptoms of Gout
- Hyperuricemia
- Presence of uric acid crystals in
joint fluid
- More than one attack of acute
arthritis
- Arthritis that develops in 1 day,
producing a swollen, red, and warm joint
- Attack of arthritis in only one
joint, usually the toe, ankle, or knee
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How Is Gout Treated?
With proper treatment, most
people with 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 both the discomfort caused by the symptoms of gout and
long-term damage of the affected joints. Treatment will help to prevent
disability due to gout.
The most common treatments
for an acute attack of gout are high doses of nonsteroidal anti-inflammatory
drugs (NSAIDs) 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. The NSAIDs most commonly prescribed for gout are
indomethacin (Indocin*) and naproxen (Anaprox, Naprosyn), which are taken
orally every day. 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.
* Brand names
included in this booklet are provided as examples only, and their inclusion
does not mean that these products are endorsed by the National Institutes of
Health or any other Government agency. Also, if a particular brand name is not
mentioned, this does not mean or imply that the product is
unsatisfactory.
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. Doctors may ask patients to take oral colchicine as often as
every hour until joint symptoms begin to improve or side effects such as
nausea, vomiting, abdominal cramps, or diarrhea make it uncomfortable to
continue the drug.
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 medicine such as
allopurinol (Zyloprim) or probenecid (Benemid) to treat hyperuricemia and
reduce the frequency of sudden attacks and the development of tophi.
What Can People With Gout Do To Stay Healthy?
- To help prevent future attacks, take
the medicines your doctor prescribes. Carefully follow instructions about how
much medicine to take and when to take it. Acute gout is best treated when
symptoms first occur.
- Tell your doctor about all the
medicines and vitamins you take. He or she can tell you if any of them increase
your risk of hyperuricemia.
- Plan followup visits with your doctor
to evaluate your progress.
- Maintain a healthy, balanced diet;
avoid foods that are high in purines; and drink plenty of fluids, especially
water. Fluids help remove uric acid from the body.
- Exercise regularly and maintain a
healthy body weight. Lose weight if you are overweight, but do not go on diets
designed for quick or extreme loss of weight because they increase uric acid
levels in the blood.
What Research Is Being Conducted To Help People With
Gout?
Scientists are studying which
NSAIDs are the most effective gout treatments, and they are analyzing new
compounds to develop safe, effective medicines to lower the level of uric acid
in the blood and to treat symptoms. They also are studying the structure of the
enzymes that break down purines in the body to achieve a better understanding
of the enzyme defects that can cause gout.
Scientists are studying the
effect of crystal deposits on cartilage cells for clues to treatment. They also
are looking at the role of calcium deposits in pseudogout in the hope of
developing new treatments. The role genetics and environmental factors play in
hyperuricemia also is being investigated.
Where Can People Find More Information About
Gout?
National Institute of
Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
National
Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
Phone:
301-495-4484 or 877-22-NIAMS (226-4267) (free of charge)
TTY:
301-565-2966
Fax: 301-718-6366
E-mail:
NIAMSInfo@mail.nih.gov
www.niams.nih.gov
NIAMS provides information
about various forms of arthritis and rheumatic diseases and bone, muscle,
joint, and skin diseases. It distributes patient and professional education
materials and also refers people to other sources of information. Additional
information and updates can be found on the NIAMS Web site.
American College of
Rheumatology/Association of Rheumatology Health Professionals
1800
Century Place, Suite 250
Atlanta, GA 30345-4300
Phone: 404-633-3777
Fax: 404-633-1870
www.rheumatology.org
This association provides
referrals to rheumatologists. The organization also provides educational
materials and guidelines about many different rheumatic diseases.
Arthritis
Foundation
1330 West Peachtree Street
Atlanta, GA 30309
Phone:
404-872-7100 or 800-283-7800 (free of charge)
or call your local chapter
(listed in the phone directory)
www.arthritis.org
This is the main voluntary
organization devoted to arthritis. The foundation publishes free pamphlets on
many types of arthritis and a monthly magazine for members that provides
up-to-date information on arthritis. The foundation also provides clinic
referrals.
Acknowledgments
The NIAMS
gratefully acknowledges the assistance of N. Lawrence Edwards, M.D., University
of Florida in Gainesville; John H. Klippel, M.D., Arthritis Foundation,
Washington, DC; Barbara Mittleman, M.D., NIAMS, NIH; Roland W. Moskowitz, M.D.,
University Hospitals of Cleveland, OH; Lawrence Ryan, M.D., Medical College of
Wisconsin in Milwaukee; and G. Bernadette Tyree, Ph.D., NIAMS, NIH, in the
preparation of this and previous versions of this booklet.
The mission of the
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS),
a part of the 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 Web site at
www.niams.nih.gov.
This booklet is not
copyrighted. Readers are encouraged to duplicate and distribute as many copies
as needed.
Additional copies
of this booklet are available from
National Institute
of Arthritis and Musculoskeletal
and Skin Diseases
NIAMS/National
Institutes of Health (NIH)
1 AMS Circle
Bethesda, MD 20892-3675
NIH Publication No.
02-5027
Publication Date: April 2002