Gout

What is it?

Gout is a disorder characterized by too much uric acid in the blood and tissues. In gout, crystals of uric acid are deposited in the joints, where they cause a type of arthritis called gouty arthritis. These same crystals can also deposit in the kidneys, where they can cause kidney stones.

There are three main causes of the high levels of uric acid that lead to gout:

a diet rich in chemicals called purines, because purines are broken down by the body into uric acid. Foods that contain high levels of purines include anchovies; nuts; and organ foods such as liver, kidney and sweetbreads.
high production of uric acid by the body. This can happen for unknown reasons. It can also occur in certain inherited genetic metabolic disorders, leukemia and during chemotherapy for cancer.
the kidneys do not excrete enough uric acid. This can be caused by kidney disease, starvation and alcohol use, especially binge drinking. This also can occur in people taking medications called diuretics (such as hydrochlorothiazide or furosemide).

Obesity or sudden weight gain can cause high uric acid levels because the body's tissues break down more purines.

In some people, gout is caused by a combination of these factors. People with a family history of gout are more likely to develop the condition.

About 90% of patients with gout are men older than 40. Gout is quite rare in younger women; when women develop gout, they are usually post-menopausal.

Symptoms

The first attack of gouty arthritis usually involves only one joint, most commonly the big toe. However, it can affect other joints, such as a knee, ankle, wrist, foot or finger. In gouty arthritis, the joint can become red, swollen and extremely tender to the touch. Typically, even a bed sheet brushing against the joint will trigger intense pain.

After the first attack of gout, later episodes are more likely to involve more than one joint at the same time. Sometimes, if gout lasts for many years, uric acid crystals can collect in the joints or tendons, under the skin, or on the outside the ears, forming a whitish deposit called a tophus.

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Illustration: Scott Leighton

Diagnosis

Your doctor will ask you about your medications, diet, alcohol use, and about any family history of gout. Your doctor will examine you, and he or she will look at your painful joints and search your skin for tophi.

Your doctor may use a sterile needle to remove a sample of fluid from your inflamed joint. This joint fluid will be examined in a laboratory for microscopic uric acid crystals, which confirm the diagnosis of gouty arthritis. Your doctor also may order blood tests to assess the function of your kidneys and to measure the level of uric acid in your blood. Imaging tests, such as ultrasound or CT scanning, can also be useful to diagnose gout.

Expected duration

Without treatment, the pain of gouty arthritis usually lasts for several days, but it is most intense during the first 24 to 36 hours. The interval between attacks varies a lot. Some people have them every few weeks, while others go years between attacks. After several gout attacks, a joint may take longer to improve or stay inflamed and painful.

Prevention

To help prevent gout:

Follow a healthy diet.
Avoid alcohol use, especially binge drinking.
Avoid dehydration.
Lose weight if you are overweight or obese.
Avoid diuretics (water pills) if possible (but discuss all medication changes with your doctor).
For most people with gout, dietary restrictions play a limited role in preventing gout attacks. However, you should avoid any foods that seem to trigger gout attacks. A heart-healthy diet such as the Mediterranean diet may reduce the risk of gout in some people.

Treatment

To treat an attack of gouty arthritis, your doctor usually will begin by prescribing a nonsteroidal anti-inflammatory drug (NSAID), such as indomethacin (Indocin), ibuprofen (Advil, Motrin and others) or naproxen (Aleve, Anaprox, Naprosyn and others). Moderate to high dose aspirin should be avoided because it can raise the level of uric acid in your blood (although low dose aspirin for prevention of heart disease or stroke has little effect on gout).

If you cannot tolerate an NSAID, or if these drugs don't work for you, your doctor may suggest a corticosteroid. Corticosteroids are most commonly given orally or injected directly into the affected joint.

A drug called colchicine may be used, but it often causes unpleasant side effects (such as nausea, vomiting, cramps, and diarrhea) before it helps the arthritis.

In rare cases an injectable medication, including anakinra or canakinumab, may be recommended, especially if other options are not effective.

To reduce uric acid in the body and prevent attacks of gout, your doctor may prescribe allopurinol (Aloprim, Zyloprim) or febuxostat (Uloric) to make your body produce less uric acid. Genetic testing (for a variant called HLA-B*5801) may be recommended to determine whether there is a high risk of an allergic reaction to allopurinol.

Another option to lower uric acid is to take a medication (such as Probenecid) that makes your kidneys excrete more uric acid than usual.

Another medication to lower uric acid is pegloticase (Krystexxa), which may be given along with methotrexate to prevent drug reactions and improve its effectiveness. In some countries, other medications are available to lower uric acid, including lesinurad, benzbromarone, and sulfinpyrazone. These medications are prescribed less often because allopurinol works so well for most people with gout.

Medications to lower uric acid levels are usually taken indefinitely. If discontinued, the uric acid level will usually rise again and attacks of gout are likely to resume.

When your doctor prescribes a medication to reduce uric acid in your blood, he or she also should prescribe a second medication to prevent a gout attack. That's because any change in uric acid levels, up or down, can trigger an attack. These preventive medications include a low dose of colchicine or a low dose of an NSAID. Once the uric acid is lowered enough for a prolonged period (about 6 months), the preventive medication can be stopped.

Treatment to lower uric acid may be recommended when:

gout attacks are frequent
gout attacks do not respond promptly to treatment
gout attacks affect more than one joint at a time
there is a history of gout along with kidney disease or kidney stones
a tophus has developed.

When to call a professional

Call your doctor whenever you have pain and swelling in a joint. If you have had gout in the past, your doctor may suggest you have NSAIDs available so you can take them at the earliest sign of an attack.

Prognosis

More than 50% of people who have had one attack of gouty arthritis will have a second, usually within six months to two years. For people with more severe disease, long-term preventive medication is highly effective at lowering uric acid, which can prevent attacks and, over months to years, cause tophi to resolve.