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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.
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.
Literally translated, arthritis means “joint inflammation.” It refers to more than 100 different diseases that affect the joints. Gout accounts for approximately 5 percent of all cases of arthritis. The disease can progress through four stages:
1. 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.
2. 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 three to ten 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.
3. Interval or intercritical gout — This is the period between acute attacks. In this stage, a person does not have any symptoms.
4. 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 article.
What Causes Gout?
A number of risk factors are associated with hyperuricemia and gout. They include:
· Genetics — Twenty percent of people with gout have a family history of the disease
· Gender and age — It is more common in men than in women and more common in adults than in children
· Weight — 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
· Alcohol consumption — Drinking too much alcohol can lead to hyperuricemia, because alcohol interferes with the removal of uric acid from the body
· Diet — Eating too many foods that are rich in purines can cause or aggravate gout in some people
· Lead exposure — In some cases, exposure to lead in the environment can cause gout
· Other health problems — Renal insufficiency, or the inability of the kidneys to eliminate waste products, is a common cause of gout in older people. Other medical problems that contribute to high blood levels of uric acid include:
o High blood pressure
o Hypothyroidism (underactive thyroid gland)
o Conditions that cause an excessively rapid turnover of cells, such as psoriasis, hemolytic anemia or some cancers
o Kelley-Seegmiller syndrome or Lesch-Nyhan syndrome, two rare conditions in which the enzyme that helps control uric acid levels either is not present or is found in insufficient quantities
· Medications. A number of medications may put people at risk for developing hyperuricemia and gout. They include:
o Diuretics, such as furosemide (Lasix*), hydrochlorothiazide (Esidrix, Hydro-chlor) and metolazone (Diulo, Zaroxolyn), 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
o Salicylate-containing drugs, such as aspirin
o Niacin, a vitamin also known as nicotinic acid
o Cyclosporine (Sandimmune, Neoral), a medication that suppresses the body’s immune system (the system that protects the body from infection and disease). This medication is used in the treatment of some autoimmune diseases, and to prevent the body’s rejection of transplanted organs.
o Levodopa (Larodopa), a medicine used to support communication along nerve pathways in the treatment of Parkinson’s disease
* Brand names included in this article 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.
Who Is Likely to Develop Gout?
Gout occurs in 8.4 of every 1,000 people. 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.
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.
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 a day, producing a swollen, red and warm joint
· Attack of arthritis in only one joint, often the toe, ankle or knee
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) 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.
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.
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. Both losartan (Cozaar), a blood pressure medication, and fenofibrate (Tricor), a triglyceride-lowering drug, also help reduce blood levels of uric acid.
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:
· 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 follow-up visits with your doctor to evaluate your progress
· Drink plenty of nonalcoholic fluids, especially water. Nonalcoholic fluids help remove uric acid from the body. Alcohol, on the other hand, can raise the levels of uric acid in your blood.
· Exercise regularly and maintain a healthy body weight. Lose weight if you are overweight, but avoid low-carbohydrate diets that are designed for quick weight loss. When carbohydrate intake is insufficient, your body can’t completely burn its own fat. As a consequence, substances called ketones form and are released into the bloodstream, resulting in a condition called ketosis. After a short time, ketosis can increase the level of uric acid in your blood.
· Avoid foods that are high in purines High-purine foods include:
o Anchovies
o Asparagus
o Beef kidneys
o Brains
o Dried beans and peas
o Game meats
o Gravy
o Herring
o Liver
o Mackerel
o Mushrooms
o Sardines
o Scallops
o Sweetbreads
What Research Is Being Conducted to Help People with Gout?
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 current areas of gout research include the following:
· Refining Current Treatments. While many medications are available to treat gout, doctors are trying to determine which of the treatments are most effective and at which dosages. Recent studies have compared the effectiveness of different NSAIDs in treating the pain and inflammation of gout and have looked at the optimal dosages of colchicine and allopurinol (a uric-acid-lowering drug) to control and/or prevent painful attacks.
· Evaluating New Therapies. A number of new therapies have shown promise in recent studies. They include infliximab (Remicade) and other biologic agents that block a chemical called tumor necrosis factor. This chemical is believed to play a role in the inflammation of gout. Another new drug therapy is febuoxostat, which works by blocking an enzyme involved in the production of uric acid.
· Discovering the Role of Foods. Gout is the one form of arthritis for which there is proof that specific foods worsen the symptoms. Now research is suggesting that certain foods may also prevent gout. In a study published in the New England Journal of Medicine, scientists found that a high intake of low-fat dairy products reduces the risk of gout in men by half. The reason for this protective effect is not yet known. Another study examining the effects of vitamin C on uric acid suggests that it may be beneficial in the prevention and management of gout and other diseases that are associated with uric acid production.
· Searching for New Treatment Approaches. Scientists are also studying the contributions of different types of cells that participate in both the acute and chronic joint manifestations of gout. The specific goals of this research are to better understand how urate crystals activate white blood cells called neutrophils, leading to acute gout attacks; how urate crystals affect the immune system, leading to chronic gout; and how urate crystals interact with bone cells in a way that causes debilitating bone lesions among people with chronic gout. The hope is that a better understanding of the various inflammatory reactions that occur in gout will provide innovative clues for treatment.
· Examining How Genetics and Environmental Factors Can Affect Hyperuricemia. Researchers are studying different populations in which gout is prevalent to determine how certain genes and environmental factors may affect blood levels of uric acid, which can leak out and crystallize in the joint, leading to gout.