Embarrassing Illnesses

Gout is caused by a build up of uric acid (urate) in your blood. Urate is a normally harmless waste product which is formed when the body breaks down substances known as purines. Two thirds of your urate is produced by your kidneys. The other third is produced by your digestive system. Purines are found naturally in the body, but are also found in some foods and certain types of alcohol.

Urate normally dissolves in your blood, and passes through your kidneys into your urine, ready to be excreted by your body. If you produce too much urate, or excrete too little, the urate builds up and can sometimes cause microscopic crystals to form, usually in a joint or in the surrounding tissue. These crystals trigger a reaction from your immune system, which causes the pain, swelling and inflammation associated with gout.

Risk factors

There are some factors which can increase the level of urate in your blood, and therefore also increase your chances of developing gout. These are outlined below.

• Men - gout rarely affects women. This is because men tend to have a naturally higher concentration of urate in their bloodstream.
• High purine diet - some foods, and certain types of alcohol, are high in purines. Foods such as kidneys, liver, anchovies, herrings and products that contain yeast can be high in purines. Beer and spirits are also high in purines. Eating lots of purine-rich food and drink can increase your level of urate significantly (see 'prevention' section).
• Medicines - certain types of medicine can increase your urate level. For example, chemotherapy drugs often affect urate levels.
• Obesity - if you are overweight, losing weight can significantly reduce your urate levels.

There are a number of other medical conditions which can also increase your risk of developing gout. These are detailed below.

• Psoriasis - causes skin cells to reproduce too quickly, leading to red, flaky and crusty skin.
• Hypertension - persistently high blood pressure.
• Diabetes
• Reduced kidney function - for example, after a kidney transplant, or if you have kidney failure
• Hyperlipidaemia - high fat and cholesterol levels in your blood.
• Vascular disease - when your arteries become thickened, narrowed, or blocked.

Studies have shown that gout often runs in families. 20% of people with gout have a close family member who also has the condition.

Gout tends to attack joints in the feet and hands because the temperature in these joints is usually lower than in the rest of the body. When urate is in your blood, it is carried by a substance known as plasma. Plasma is the liquid part of your blood responsible for carrying proteins and chemicals. When it is cooler, the urate in your blood separates out from the plasma, allowing it to build up and form into the urate crystals that cause the pain associated with gout.

In some cases, it is not known what triggers a gout attack. Some people with high levels of uric acid in their system never suffer from gout, and some people who are affected by gout have a normal level of uric acid.