Gout is caused by excess blood levels of uric acid (hyperuricaemia), which is produced as a normal breakdown product of protein in the diet. Normally uric acid is removed by the kidneys, but if excess is produced or the kidneys fail to work efficiently, high levels build up in the body and precipitate as crystals in the lubricating fluid of a joint. Under a microscope the crystals look like double-ended needles.
An alcoholic binge or eating a lot of meat can start an attack in someone who is susceptible, and there is a tendency for the disease to run in families. Most victims are men and it usually starts between 30 and 50 years of age.
The main symptom is an exquisitely tender, red, swollen and painful joint. The most common joint to be involved is the ball of the foot, but almost any joint in the body may be involved. In severe attacks, a fever may develop, along with a rapid heart rate, loss of appetite and flaking of skin over the affected joint. Attacks usually start very suddenly, often at night, and may occur every week or so, or only once in a lifetime. In chronic cases uric acid crystals can form lumps (tophi) under the skin around joints and in the ear lobes. More seriously, the crystals may damage the kidneys and form kidney stones.
High levels of uric acid found on blood tests confirm the diagnosis, and a needle may be used to take a sample of fluid from within the joint for analysis in difficult cases.
The management of gout takes two forms – treatment of the acute attack, and prevention of any further attacks.
Acute attacks are cured by the combination of non-steroidal anti-inflammatory drugs (eg. indomethacin, naproxen) and/or colchicine (a hypouricaemic). Aspirin is contraindicated in acute gout as it may elevate serum uric acid levels and aggravate the symptoms. Rest of the affected joint to control the pain and prevent further damage is important.
Prevention involves taking tablets (eg. allopurinol, probenecid, sulfinpyrazone) daily for the rest of the patient’s life to prevent further attacks, not consuming excess alcohol, keeping weight under control, drinking plenty of liquids to prevent dehydration, avoiding overexposure to cold, not exercising to extremes and avoiding foods that contain high levels of purine producing proteins which metabolise to uric acid (eg. prawns, shellfish, liver, sardines, meat concentrates and game birds). If the prevention tablets are missed an attack of gout can follow very quickly.
Gout can be controlled and prevented easily in most cases, provided the patient understands the problem and co-operates with treatment.