Gout

What is gout? What is hyperuricemia?

Gout is a condition that results from an overload of crystals of uric acid depositing in tissues of the body and features recurring attacks of joint inflammation (arthritis). Chronic gout can lead to deposits of hard lumps of uric acid in and around the joints, decreased kidney function, and kidney stones.

Gout has the unique distinction of being one of the most frequently recorded medical illnesses throughout history. It is often related to an inherited abnormality in the body's ability to process uric acid. Uric acid is a breakdown product of purines that are part of many foods we eat. An abnormality in handling uric acid can cause attacks of painful arthritis (gout attack), kidney stones, and blockage of the kidney-filtering tubules with uric-acid crystals, leading to kidney failure. On the other hand, some patients may only develop elevated blood uric-acid levels (hyperuricemia) without having arthritis or kidney problems. The term "gout" commonly is used to refer to the painful arthritis attacks.

Gouty arthritis is usually an extremely painful attack with a rapid onset of joint inflammation. The joint inflammation is precipitated by deposits of uric-acid crystals in the joint fluid (synovial fluid) and joint lining (synovial lining). Intense joint inflammation occurs as white blood cells engulf the uric-acid crystals and release chemicals of inflammation, causing pain, heat, and redness of the joint tissues.

Who is affected by gout?

Approximately 1 million people in the United States suffer from attacks of gout. (Did you know that none other than Benjamin Franklin had terrible gouty arthritis!) Gout is nine times more common in men than in women. It predominantly attacks males after puberty, with a peak age of 75. In women, gout attacks usually occur after menopause.

While an elevated blood level of uric acid (hyperuricemia) may indicate an increased risk of gout, the relationship between hyperuricemia and gout is unclear. Many patients with hyperuricemia do not develop gout, while some patients with repeated gout attacks have normal or low blood uric-acid levels. Among the male population in the United States, approximately 10% have hyperuricemia. However, only a small portion of those with hyperuricemia will actually develop gout.

What are symptoms of gout?

The small joint at the base of the big toe is the most common site of an acute gout attack of arthritis. Other joints that can be affected include the ankles, knees, wrists, fingers, and elbows. Acute gout attacks are characterized by a rapid onset of pain in the affected joint followed by warmth, swelling, reddish discoloration, and marked tenderness. Tenderness can be intense so that even a blanket touching the skin over the affected joint can be unbearable. Patients can develop fever with the acute gout attacks. These painful attacks usually subside in hours to days, with or without medication. In rare instances, an attack can last for weeks. Most patients with gout will experience repeated attacks of arthritis over the years.
Uric-acid crystals can deposit in tiny fluid-filled sacs (bursae) around the joints. These urate crystals can incite inflammation in the bursae leading to pain and swelling around the joints, a condition called bursitis. In rare instances, gout leads to a more chronic type of joint inflammation which mimics rheumatoid arthritis.

In chronic (tophaceous) gout, nodular masses of uric acid crystals (tophi) deposit in different soft tissue areas of the body. Even though they are most commonly found as hard nodules around the fingers, at the tips of the elbows, and around the big toe, tophi nodules can appear anywhere in the body. They have been reported in unexpected areas such as in the ears, vocal cords, or (rarely) around the spinal cord!

How is gouty arthritis diagnosed?

Gout is suspected when a patient reports a history of repeated attacks of painful arthritis at the base of the toes. Ankles and knees are the next most commonly involved joints in gout. Gout usually attacks one joint at a time, while other arthritis conditions, such as systemic lupus and rheumatoid arthritis, usually attack multiple joints simultaneously.

The most reliable test for gout is finding uric-acid crystals in the joint fluid obtained by joint aspiration (arthrocentesis). Arthrocentesis is a common office procedure performed under local anesthesia. Using sterile technique, fluid is withdrawn (aspirated) from the inflamed joint, using a syringe and needle. The joint fluid is then analyzed for uric-acid crystals and for infection. Shiny, needle-like uric-acid crystals are best viewed with a polarizing microscope. The diagnosis of gout can also be made by finding these urate crystals from material aspirated from tophi nodules and bursitis fluid.

Some patients with a classic history and symptoms of gout can be successfully treated and presumed to have gout without undergoing arthrocentesis. However, establishing a firm diagnosis is still preferable since other conditions can mimic gout. These include another crystal-induced arthritis called pseudogout, psoriatic arthritis, rheumatoid arthritis, and even infection.

X-rays can sometimes be helpful, and may show tophi-crystal deposits and bone damage as a result of repeated inflammations. X-rays can also be helpful for monitoring the effects of chronic gout on the joints.