Gout is a form of arthritis associated with high blood levels of a compound called uric acid, which is a normal by-product of the breakdown of food in the body. In particular, uric acid is generated by the metabolism of compounds called purines, which are present in organ meats (e.g. liver and kidneys), seafood (especially anchovies), and some vegetables (e.g. asparagus and mushrooms).
Under usual circumstances, the body maintains normal uric acid levels via an ongoing process in which uric acid is dissolved in the blood, filtered through the kidneys and excreted in the urine. If factors cause the body to produce excessive quantities of uric acid, or prevent its effective break down crystals of sodium urate may form in the joints causing the characteristic pain, swelling and redness of gout.
Uric acid crystals may also form in the kidneys, where they can cause kidney stones.
Gout runs in families, and if one of your parents had gout, you have a one in five chance of experiencing it too. It affects men more often than women, especially those aged 30-50 years old. Women rarely experience gout prior to menopause, and are more likely to be affected at 50-70 years of age.
Being overweight or suffering from kidney disease are also risk factors for gout.
Factors that may trigger an attack of gout include:
- Trauma (for example, undergoing surgery).
- Being dehydrated or not drinking enough water.
- Alcohol ingestion, especially of beer.
- Dietary excess, and in particular, excessive consumption of foods containing purines, such as organ meat, seafood (especially anchovies, herring, mackerel, sardines), and yeast-containing foods such as beer and yeast spreads).
- Fasting or consuming a severely restricted diet.
- Consumption of high levels of fructose, an ingredient found in large quantities in some soft drinks (but not those produced in Australia) and some fruit juices.
- Hormonal changes.
- The use of certain pharmaceutical drugs, including some diuretics.
Pseudo-gout is similar to gout, but is caused by different types of crystals (calcium pyrophosphate crystals) forming in joints, particularly in cartilage. The cause of pseudo-gout is unknown, but it has been linked with low magnesium levels in the blood, over-activity of the parathyroid gland, the storage of excessive quantities of iron, and genetic factors.