Gout is a condition in which uric acid accumulates in the blood stream and then in the joint spaces. Uric acid crystals can build up and develop swellings and bumps called tophi. These tophi can be treated with medicines or surgery.
Acute gout is a painful condition that often affects only one joint. Chronic gout is the repeated episodes of pain and inflammation. More than one joint may be affected.
Causes of Gout
Gout is caused by having a higher-than-normal level of uric acid in your body. This may occur if:
- Your body makes too much uric acid
- Your body has a hard time getting rid of uric acid
- If too much uric acid builds up in the fluid around the joints (synovial fluid), uric acid crystals form. These crystals cause the joint to swell and become inflamed.
The exact cause is unknown. Gout may run in families. The problem is more common in men, in women after menopause, and people who drink alcohol. As people become older, gout becomes more common.
Gout and Kidney Disease
Gout is more common in kidney disease because the body has difficulty getting rid of uric acid in the urine.
There are several types of inherited kidney disease that are associated with a high frequency of gout. These conditions are studied by the Rare Inherited Kidney Disease Research Team at Wake Forest School of Medicine, led by Anthony Bleyer, M.D., M.S., a professor in the Section of Nephrology.
The conditions that cause gout and kidney disease include uromodulin kidney disease and inherited kidney disease due to mutations in renin.
These conditions are inherited, often with many family members affected. Sometimes, only a parent and child are affected in a family.
What is Uric Acid?
Uric acid is a break down product of DNA - the genetic material of the body. DNA and related nucleic acids are continuously being made and replaced. This results in the production of uric acid. Uric acid enters the bloodstream and is then excreted out of the body by the kidneys.
Why do individuals with high uric acid levels develop gout?
Uric acid in the blood stream deposits in the joints and forms crystal collections. White cells are activated by these crystals, and inflammation (and pain develop). Crystals tend to deposit in the big toe because this is the part of the body with the lowest temperature.
Why do individuals develop high uric acid levels?
The major reason people develop gout is because their kidneys have difficulty excreting uric acid. This happens in 80% of cases of gout. Over-production of uric acid occurs in some patients due to inherited (genetic disorders). In patients prone to gout, eating meat, liver, shellfish, and drinking beer can lead to gout attacks. However, kidney disease in the primary reason most people have gout.
What Are Tophi, and What Causes Them?
Tophi occur when the person’s blood uric acid level remains high over a long period of time. The uric acid deposits in joints and forms precipitates. These precipitates can become quite large, resulting in bumps and swellings on the joints. These swellings can occur on the knee, the elbow, the big toe, and many other joints. They can be quite painful. Sometimes they open up and leak white, chalky material that is composed of uric acid.
Symptoms of acute gout:
- Only one or a few joints are affected. The big toe, knee, or ankle joints are most often affected.
- The pain starts suddenly, often during the night. Pain is often described as throbbing, crushing, or excruciating.
- The joint appears warm and red. It is usually very tender and swollen (it hurts to put a sheet or blanket over it).
- There may be a fever.
- The attack may go away in a few days, but may return from time to time. Additional attacks often last longer.
People will have no symptoms after a first gout attack. Many people will have another attack in the next 6 to12 months.
Some people may develop chronic gout. This is also called gouty arthritis. This condition can lead to joint damage and loss of motion in the joints. People with chronic gout will have joint pain and other symptoms most of the time.
Tests that may be done include:
- Synovial fluid analysis (shows uric acid crystals)
- Uric acid - blood
- Joint x-rays (may be normal)
- Synovial biopsy
- Uric acid - urine
A uric acid level in the blood over 7 mg/dL is high. But, not everyone with a high uric acid level has gout.
Take medicines for gout as soon as you can if you have a sudden attack.
Take nonsteroidal anti-inflammatory drugs (NSAIDs) when symptoms begin. Talk to your health care provider about the correct dose. You will need stronger doses for a few days.
- Your provider may prescribe strong painkillers such as codeine, hydrocodone, and oxycodone.
- A prescription medicine called colchicine helps reduce pain, swelling, and inflammation.
- Corticosteroids (such as prednisone) can also be very effective. Your provider may inject the inflamed joint with steroids to relieve the pain.
- The pain often goes away within 12 hours of starting treatment. Most of the time, all pain is gone within 48 hours.
You may need to take daily medicines to decrease the uric acid level in your blood if:
- You have several attacks during the same year or your attacks are quite severe.
- You have damage to joints.
- You have tophi.
- You have kidney disease or uric acid kidney stones.
Diet and lifestyle changes may help prevent gouty attacks:
- Decrease alcohol.
- Lose weight.
- Exercise daily.
- Limit your intake of red meat and sugary beverages.
- Choose healthy foods, such as dairy products, vegetables, nuts, legumes, fruits and whole grains.
Gout in Children and Teens
If a child or teenager has gout, it is important that blood and urine tests be done to determine why gout has occurred. It is usually a sign of an underlying problem that is often easily treated.
In children, the first test to do if gout is suspected is to measure the blood uric acid level. If this is elevated (>6), this could be a sign that gout is present. Other important procedures are for a doctor to insert a needle into the affected joint, withdraw fluid, and examine this fluid for uric acid crystals.
Causes of gout in children and teenagers include:
- Inherited conditions that cause over-production of uric acid. These include HPRT deficiency (also known as Lesch Nyhan syndrome) and PRPP synthetase overactivity. These disorders are uncommon but are easily tested for. Patients produce extra uric acid and can have gout and kidney stones containing uric acid. These conditions usually occur in boys but can occasionally happen in girls as well.
- Kidney diseases resulting in decreased ability of the body to get rid of uric acid. These can include:
- The most common type is due to mutations in the gene that produces a protein called uromodulin. In this condition, patients develop gout in their teenage years and have slow worsening of kidney failure over time. There are usually many other family members who have had gout or kidney disease.
- Another cause of this condition is a mutation in the gene that makes the protein renin. In this condition, children have a history of relatively low blood pressure, anemia (low blood count), and mild kidney disease. The blood potassium levels are often mildly elevated. The anemia is present from the time the child is young, and often the cause of the anemia is not known. This condition is easily diagnosed and treatable with medications. Patients with this condition often have a father or mother who has gout, anemia as a child, and kidney disease.
- Any type of kidney disease can also cause gout in childhood.
- Patients who are overweight and have high blood pressure can also be at risk for gout. This usually occurs in the 20’s and 30’s, but it is becoming more common in young individuals. This is called Metabolic Syndrome.