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Gout is characterised by excessively high levels of uric acid in the blood (known as hyperuricaemia in medical jargon). This high level of uric acid causes crystals to form in the joints and soft tissues. This is when your immune system can react and start to attack these crystals. An inflammatory reaction is created, leading to pain, redness and swelling in the affected joint.

Gout attacks occur intermittently and can vary in severity and duration. Generally, it is the joints of the lower limbs (knees, ankles and feet) that are most often affected.

Uric acid is produced when the body breaks down chemical compounds. These compounds are already present naturally in cells and in protein-rich foods. The blood then transports the uric acid to the kidneys, where it is eliminated in the urine.

Only if the concentration is too high can it accumulate and form crystals. This accumulation can also produce small hard bumps under the skin known as tophus, as well as kidney stones in the kidneys. Symptoms of a gout attack often appear at night and worsen within 24 hours. Not everyone with hyperuricaemia develops forced gout.

In order to diagnose gout, your doctor will ask you questions during the clinical examination to find out about your eating habits and any self-medication you may have taken recently. He will also want to know when the symptoms appeared and how long they lasted. The intensity of the pain and which joints are affected will also help him in his diagnosis.

He may then prescribe additional tests, such as a blood test, a urine test or a puncture of the synovial fluid in the affected joint.

The purpose of the blood test is to check uric acid levels, although a high level is not indicative of a gout attack. You may be asked to repeat the blood test after the symptoms have disappeared, as uric acid levels tend to fall during an attack.

A urine test will enable you to assess the amount of uric acid processed by the kidneys. A puncture will reveal the presence of uric acid crystals, confirming or refuting the diagnosis.

In some cases, we can identify warning signs called "prodromes" of a gout attack. In fact, a certain number of gout sufferers are sometimes or often warned of the imminence of their attacks by local prodromal signs:

• Discomfort in the affected joint.
• Heaviness, cramps or twitching in the lower limbs.
• General signs: nervousness, fatigue and insomnia above all, digestive problems, shivering, fever, difficulty in urinating in some cases.

No. Although the first metatarsophalangeal joint is the most frequently affected, gout can also inflame the tarsus (instep) of the foot or the ankle, confusing the patient and inexperienced doctors into thinking that it is a sprain (even if there has been no trauma to the ankle). It can also inflame other joints such as the knee, the elbow (especially the olecranial bursa, which "cushions" the back of the elbow), the wrist, etc.

Hyperuricaemia and gout are two different concepts. Hyperuricaemia means having high levels of uric acid in the blood, i.e. levels above 6.8 mg/dL (7 mg/dL, by convention), as this is the crystallisation point. We speak of gout when there are deposits of urate crystals in the tissues (joints, kidneys, etc.). Although only one in ten people with high uric acid will suffer from gout, it is often preceded and accompanied by chronic hyperuricaemia.

Having high blood uric acid on a regular basis may reflect that we are unable to eliminate it properly, that we produce more than normal, or both. If this goes on for years, it can lead to crystalline deposits, with various symptoms (joint, kidney, etc.) or with the formation of lesions under the skin called tophi (aggregates of crystals).

Although diet is important, gout is caused in more than 90% of cases by a problem of uric acid elimination by the kidneys. It is not advisable to abuse foods rich in purines: beer (with and without alcohol), high-proof alcoholic drinks and sweetened drinks (soft drinks, etc.), offal, red meat and game, seafood and oily fish (sardines, anchovies, etc.). Tomatoes can facilitate joint attacks in gout patients, but moderate consumption of tomatoes does not usually cause problems, as animal proteins produce more purines in the body than vegetable proteins.

It is advisable to drink 1-2 litres of water a day (especially if urate kidney stones are present) and skimmed dairy products, cherries, foods rich in vitamin C and coffee (moderate consumption) are beneficial. On the other hand, overweight and obesity should be avoided and combated by trying to be physically active several days a week.