Gout is a common metabolic disorder caused by increased uric acid levels in the blood (hyperuricaemia). This uric acid can be deposited in the joints as crystals, where it triggers inflammatory responses. Gout can affect any joint, but the metatarsophalangeal joints of the big toes are most frequently affected.

Visualisation of gout on the big toe
Visualisation of gout on the big toe

Overview of gout

Gout is a type of inflammatory arthritis caused by the deposition of uric acid crystals in the joints. These crystals lead to painful inflammation known as gout attacks or gout flares, which typically cause the affected joints to swell and become extremely tender within a few hours. In addition to the joints, soft tissue, tendons and bursae (fluid-filled sacs that reduce friction between tissue in the body) can also become inflamed, which can cause a variety of additional symptoms.

Causes and risk factors

Gout is caused by increased uric acid levels in the blood (hyperuricaemia), which is produced when the body breaks down proteins. If protein metabolism is increased or the body cannot properly excrete uric acid via the urine, uric acid can accumulate in the blood.

Many patients who suffer from gout have a genetic predisposition where they excrete less uric acid via the kidneys. In addition to this genetic element, there are other risk factors that affect a person’s chances of developing gout:

Sex

Gout affects men more often than women; this difference is mainly due to hormonal factors. Before the menopause, women have lower uric acid levels because oestrogen promotes the excretion of uric acid via the kidneys. This means that women are less likely to get gout in their younger years.

Excess weight

Being overweight increases the production of uric acid in the body while also making it more difficult to excrete it via the kidneys. A higher body fat percentage can also lead to insulin resistance, which in turn raises uric acid levels and increases the risk of gout attacks.

Lack of physical activity

A lack of physical activity can lead to reduced blood circulation. This makes it harder for the body to excrete uric acid and increases the risk of uric acid crystals being deposited in the joints.

High meat consumption

Meat, especially red meat, is rich in purines, which are broken down into uric acid in the body. Consuming a large amount of purine-rich foods can raise uric acid levels in the blood, which significantly increases the risk of gout attacks.

Excessive alcohol consumption

Alcohol promotes the production of uric acid and also inhibits its excretion via the kidneys, which leads to an accumulation of uric acid in the blood.

Disease progression

Gout is caused by an increased level of uric acid in the blood. If the uric acid level is above 6 mg/dl, the uric acid can be deposited in the form of crystals in joints and soft tissue. If the uric acid level exceeds 9 mg/dl, the risk of a gout attack increases considerably. If uric acid concentration remains high, chronic gout can develop over time.

Acute gout flare

Typical triggers of a gout flare are often related to diet, for example a rich meal with a lot of meat can lead to an acute attack.

Chronic gout

If uric acid levels remain elevated, gout can develop from an acute to a chronic form. Chronic gout often affects several joints at the same time and can lead to the formation of gout nodules, called ‘tophi’, on cooler parts of the body such as the elbows, feet, outer ear and fingers. In chronic gout, uric acid crystals can also be deposited in the kidneys and lead to kidney stones. In addition, chronic gout can lead to secondary osteoarthritis , which results in progressive wear and tear of the affected joints.

Symptoms

The symptoms of gout can vary depending on the stage of the disease, with a distinction being made between acute attacks of gout and chronic gout.

Symptoms of an acute gout attack

The symptoms of a gout attack usually occur suddenly, often at night. The affected joint quickly becomes painful, inflamed, swollen and hot. During an attack, even light pressure, such as the weight of a duvet, can cause unbearable pain. The pain worsens rapidly and usually reaches its peak within six to twelve hours. The affected joint usually heals on its own within one to two weeks.

Symptoms of chronic gout

Chronic gout is characterised by repeated attacks of gout and persistent inflammation that can affect several joints. Gout nodules (tophi) form, which appear as hard, painless deposits of uric acid crystals in joints, skin and soft tissue. These lumps can cause permanent joint damage and severely restrict mobility.

Diagnosis

An orthopaedic specialist can usually diagnose gout based on the typical symptoms and the patient’s medical history. Painful and swollen, red skin at the metacarpophalangeal joint or interphalangeal joint of the big toe is particularly characteristic.

Another important step in reliably diagnosing gout is to send some of the patient’s synovial (joint) fluid for analysis. The sample is taken in a procedure called joint aspiration or arthrocentesis, where a small amount of fluid is removed from the joint in question using a fine needle and examined in a laboratory for uric acid crystals. Joint aspiration is often used if the symptoms are unclear or to rule out other possible causes such as chondrocalcinosis (pseudogout).

Another common method for diagnosing gout is to measure the uric acid level in the blood. However, it should be noted that there are people who never suffer a gout attack despite having high uric acid levels (asymptomatic hyperuricaemia). In addition, the uric acid level can often drop into the normal range during a relapse, making the use of blood analysis as the sole method for diagnosis limited.

Treatment

Gout is treated by alleviating the joint inflammation and reducing the increased urine level. Anti-inflammatory medication and painkillers are used to treat any joint inflammation. The elevated urine level can be lowered with medication which either reduces the formation of uric acid or increases the excretion of uric acid. The treatment is supported with nutritional advice. As a general rule: less meat, fish, offal and alcohol and more water, vegetables and milk products.

Prevention

To prevent gout, it is important to keep uric acid levels in the blood low, and the following preventive measures can help:

  • Low-purine diet (limited consumption of red meat, seafood and alcohol)
  • Regular physical exercise
  • Maintaining a healthy body weight
  • Staying sufficiently hydrated
  • Only taking medication that increases uric acid levels after consulting a doctor

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