The condition was first identified as early as 2,640 BC by the ancient Egyptians; But, despite its long history, gout remains a major public health concern, with an increasing number of people suffering from what can be an extremely painful condition.
Gout has also been related to an increased incidence of cardiovascular and metabolic disease.
This complex form of arthritis is characterized by the onset of sudden and severe pains. Fortunately, gout is treatable and there are preventative measures that can be taken to reduce the risk of developing the painful condition.
Contents of this article:
Here are some key points about gout. More detail and supporting information is in the main article.
- Gout is a form of arthritis caused by excess uric acid in the bloodstream.
- The symptoms of gout are due to the formation of uric acid crystals in the joints and the body's response to them.
- Gout most classically affects the joint in the base of the big toe.
- Gout attacks often occur without warning in the middle of the night.
- Most gout cases are treated with specific medications.
What is gout?
Gout can affect the base of the big toe. When affecting this area, the condition can also be referred to as podagra.
Gout is a common form of inflammatory arthritis - a condition affecting the joints and musculoskeletal system.
It is the most common form of inflammatory arthritis in men, and although it is more likely to affect men, women become more susceptible to it after the menopause.
The condition is characterized by sudden and severe pains, redness, and tenderness in the joints, most classically in the base of the big toe. When affecting the big toe, gout is sometimes called podagra.
These symptoms occur when uric acid, a normal product metabolism, is deposited in the form of needle-like crystals in tissues and fluids within the body.
The body views these crystals as foreign, and white cells infiltrate the joint, causing inflammation. Chalky deposits of uric acid known as tophi can also form as lumps under the skin surrounding the joints.
The Centers for Disease Control and Prevention (CDC) report that 8.3 million Americans were affected by gout in 2007-2008.
What causes gout?
Gout is caused initially by an excess of uric acid in the blood (hyperuricemia). Uric acid is produced in the body during the breakdown of purines - chemical compounds that are found in high amounts in certain foods such as meat, poultry, and seafood.
Normally, uric acid is dissolved in the blood and is excreted from the body in urine via the kidneys. If too much uric acid is produced, or not enough is excreted, it can build up and form needle-like crystals that trigger inflammation and pain in the joints and surrounding tissue.
Risk factors for gout
There are a number of factors that can increase the likelihood of hyperuricemia, and therefore gout:
Age and gender - men produce more uric acid than women, though women's levels of uric acid approach those of men after the menopause.
Genetics - a family history of gout increases the likelihood of the condition developing.
Lifestyle choices - alcohol consumption interferes with the removal of uric acid from the body. Eating a high-purine diet also increases the amount of uric acid in the body.
Lead exposure - chronic lead exposure has been linked to some cases of gout.
Medications - certain medications can increase the levels of uric acid in the body; these include some diuretics and drugs containing salicylate.
Weight - being overweight increases the risk of gout as there is more turnover of body tissue, which means more production of uric acid as a metabolic waste product. Higher levels of body fat also increase levels of systemic inflammation as fat cells produce pro-inflammatory cytokines.
Recent trauma or surgery - increases risk.
Other health problems - renal insufficiency and other kidney problems can reduce the body's ability to efficiently remove waste products, leading to elevated uric acid levels. Other conditions associated with gout include high blood pressure (hypertension), diabetes, and hypothyroidism (underactive thyroid gland).
Signs and symptoms of gout
Gout patients often have acute inflammation around their joints.
Gout usually becomes symptomatic suddenly without warning, often in the middle of the night. The main symptoms are intense joint pain that subsides to discomfort, inflammation, and redness.
The pain can be excruciating; a veteran visiting a Hospital in Birmingham, AL, said:
"I've been shot, beat up, stabbed, and thrown out of a helicopter, but none of that compared to the gout."
Gout frequently affects the large joint of the big toe, but can also affect the ankles, knees, elbows, wrists, and fingers.
There are four stages through which gout progresses:
It is possible for a person to have hyperuricemia (elevated uric acid levels) without any outward symptoms. At this stage, treatment is not required, though urate crystals are being deposited in tissue and causing slight damage.
People with asymptomatic hyperuricemia may be advised to take steps to address any possible factors contributing to uric acid build-up.
This stage occurs when the urate crystals that have been deposited suddenly cause acute inflammation and intense pain. This sudden attack is referred to as a "flare" and will normally subside within 3-10 days. Flares can sometimes be triggered by stressful events, alcohol and drugs, as well as cold weather.
Interval or intercritical gout
This stage is the period in between attacks of acute gout. Subsequent flares may not occur for months or years, though if not treated, over time, they can last longer and occur more frequently. During this interval, further urate crystals are being deposited in tissue.
Chronic tophaceous gout
Chronic tophaceous gout is the final stage and the most debilitating form of gout. Permanent damage may have occurred in the joints and the kidneys. The patient can suffer from chronic arthritis and develop tophi - big lumps of urate crystals - in cooler areas of the body such as the joints of the fingers.
It takes a long time without treatment to reach the stage of chronic tophaceous gout - around 10 years. It is very unlikely that a patient receiving proper treatment would progress to this stage.
Tests and diagnosis
Gout can be tricky to diagnose as its symptoms, when they do appear, are similar to those of other conditions. While hyperuricemia occurs in the majority of people that develop gout, it may not be present during a flare. On top of that, the majority of people with hyperuricemia do not develop gout.
One diagnostic test that doctors can carry out is the joint fluid test, where fluid is extracted from the affected joint with a needle. The fluid is then examined to see if any urate crystals are present.
As joint infections can also cause similar symptoms to gout, a doctor can look for bacteria when carrying out a joint fluid test in order to rule a bacterial cause.
Doctors can also do a blood test to measure the levels of uric acid in the blood, but, as mentioned, people with high uric acid levels do not always experience gout. Equally, some people can develop the symptoms of gout without having increased levels of uric acid in the blood.
Finally, doctors can search for urate crystals around joints or within a tophus using ultrasound or computerized tomography (CT) scans. X-rays cannot detect gout, but may be used to rule out other causes.
One condition that is easily confused with gout is pseudogout. The symptoms of pseudogout are very similar to those of gout.
The major difference between gout and pseudogout is that the joints are irritated by calcium phosphate crystals rather than urate crystals. Pseudogout requires different treatment.
Treatment and prevention
Drinking 2-4 liters of water a day reduces the risk of gout.
The majority of gout cases are treated with medication. Medication can be used to treat the symptoms of gout attacks, prevent future flares, and reduce the risk of gout complications such as kidney stones and the development of tophi.
Commonly used medications include nonsteroidal anti-inflammatory drugs (NSAIDs), colchicine, or corticosteroids. These reduce inflammation and pain in the areas affected by gout and are usually taken orally.
Medications can also be used to either reduce the production of uric acid (xanthine oxidase inhibitors such as allopurinol) or improve the kidney's ability to remove uric acid from the body (probenecid).
There are many lifestyle and dietary guidelines that can be followed to protect against future flares or prevent gout from occurring in the first instance:
- maintain a high fluid intake (2-4 liters a day)
- avoid alcohol
- maintain a healthy body weight
- eat a balanced diet
- limit fish, meat, and poultry intake
Individuals with gout should avoid low-carbohydrate diets; low intake of carbohydrate means that the body is unable to properly burn fat stores, leading to the release of substances called ketones into the bloodstream.
This rise in ketones can result in a condition called ketosis that can increase the level of uric acid in the blood.
It is most important to avoid foods that are high in purines, to ensure that the levels of uric acid in the blood do not get too high. Here is a list of high-purine foods to be wary of:
- beef kidneys
- dried beans and peas
- game meats
Asparagus, beans, some other plant-based foods, and mushrooms are also sources of purines, but research suggests that these do not trigger gout attacks and do not impact uric acid levels.
Various epidemiological studies have shown that purine-rich vegetables, whole grains, nuts and legumes, and less sugary fruits, coffee, and vitamin C supplements decrease the risk of gout, whereas red meat, fructose-containing beverages, and alcohol increase the risk.
In some cases, gout can develop into more serious conditions, such as:
- Kidney stones - if urate crystals collect in the urinary tract, they can become kidney stones.
- Recurrent gout - some people only ever have one flare up; others may have regular recurrences, causing gradual damage to the joints and surrounding tissue.
Uric acid's role in gout has been clearly defined and understood. As a result of this and the wide availability of relevant medications, gout is a very controllable form of arthritis.