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Uric acid is a waste product from the digestion process, and an excess of it is responsible for gout and kidney stones. The liver digests purines into uric acid, and the kidneys metabolise uric acid into urea, which is excreted in urine.
Uric acid in the blood is a toxin, and if the kidneys can't deal with it, the body will find somewhere to dump the excess. This will usually be in a lower extremity, such as a big toe, though any leg joints including the ankles and knees could be affected. The sodium salt, sodium urate is crystallised out in the joint. These crystals lead to painful swelling, which is what gout is. Sometimes, you can feel bumps under the skin near the joints, which are called tophi. These are where accumulations of crystals have built up and hardened.
There are several factors that can lead to a build up of uric acid:
Rich food containing purines: foods such as red meat, especially liver and other offal, shellfish and some other fish (herrings, mackerel, anchovies). These should be avoided altogether by gout sufferers. Note that some vegetables contain purines, so gout sufferers should avoid an excess of mushrooms, legumes, asparagus, cauliflower, spinach and wheat.
lack of water. The kidneys need plenty of water in order to function efficiently. 2 litres per day are recommended by dieticians. Diuretics are also bad, as they reduce or prevent this flushing out action.
Alcohol, especially wine and beer. Alcohol has the effect of overloading the liver and kidneys. Wines and real ale are especially bad, as they contain yeast, which is high in purines.
Congenital predisposition. Some people have kidneys that aren't working efficiently. some may have a reaction to uric acid that causes more precipitation, or more inflammation.
In my case, I know the circumstances that brought on gout within 24 hours. I was on a week when I was finishing early, and I was due to go to a staff evening with my employers at 7pm. I filled the intervening time by having beers with a friend before the meeting. I did not know that the meeting woud consist of sitting through two hours of presentations without a break.
After the meeting, I was bursting for the loo. This probably put my kidneys in a bad mood anyway. To finish off, there were trays of nibbles, including some of what I now know to be the worst foods for gout - all this and I was drinking red wine.
It turns out that my mother has suffered from gout in the past.
Treatments
After the initial course of NSAIDs for gout, which deal with symptoms, there are different long term approaches to eliminating the uric acid.
Allopurinol. This is a drug which acts as an enzyme blocker, which inhibits the action of xanthine oxidase in the liver. This is the enzyme that breaks down purines into uric acid.
The decision to take allopurinol is often a permanent one, and the effect of stopping taking the drug can result in a uric acid flush and acute, extreme gout. I decided this drug was not for me.
Probenecid. This works by increasing the rate that uric acid is excreted. Drinking lots of water is important with this treatment, as otherwise, the uric acid won't get flushed from the system.
This drug cannot be used if there are other problems with the kidneys.
There are known natural agents, which assist in the breaking down of uric acid, or enhance the kidneys function.
Of note are celery seeds, dark berries and pineapple juice. These should be accompanied by lifestyle changes to eliminate the causes of gout where possible.
References