Gout

Gout is a very painful form of arthritis caused by crystals that form in and around the joints.

It’s the most common type of inflammatory arthritis. It’s more common in men and you’re more likely to get it as you get older.

Gout occurs in people who have high levels of urate in their blood, but having urate in your blood doesn’t mean you’ll develop gout. It’s normal and healthy to have some urate in your bloodstream.

Urate is created every day when our bodies break down purines. Purines are chemicals that are naturally created in our body, but they are also present in certain foods.

People used to think that gout was caused by overeating and drinking too much alcohol. While this can make attacks of gout more likely, it’s not the whole story.

In any day, about three-quarters of the urate in our bodies comes from the breakdown of purines produced within our body, while only about a quarter comes from the breakdown of purines in food and drink we consume.

As urate levels build up, your body gets rid of any extra through your kidneys and in your wee. But if your body is making too much urate, or your kidneys are unable to get rid of enough of it, then levels start to rise.

If urate levels stay too high, urate crystals can slowly start forming. They mainly occur in and around firm joint tissues, such as the cartilage. But crystals can also appear under your skin and may even occur in your internal organs, such as the kidneys.

Attacks

When you have gout, urate crystals can build up in your joints for years without you knowing they are there. When there are a lot of crystals in your joints, some of them can spill out from the cartilage into the space between the two bones in a joint.

The tiny, hard, sharp crystals can rub against the soft lining of the joint, called the synovium, causing a lot of pain swelling and inflammation. When this happens, it’s known as an attack or flare of gout.

During an attack of gout the affected joint becomes:

• very painful
• tender
• red
• hot
• swollen.

The skin over the joint often appears shiny and may peel off a little as the attack settles.

Attacks usually come on very quickly, often during the night. Doctors describe this sudden development of symptoms as ‘acute’.

The attack usually settles after about five to seven days, but it can go on for longer.

If gout is left untreated, attacks can become more common and may spread to new joints.

Attacks typically affect the joint at the base of the big toe and often start in the early hours of the morning. The symptoms develop quickly and are at their worst within just 12 to 24 hours of first noticing that anything is wrong.

Any light contact with the affected joint is very painful – even the weight of a bedsheet or wearing a sock can be unbearable.

Although gout most often affects the big toe, other joints may also be affected, including:

• other joints in your feet
• ankles
• knees
• elbows
• wrists
• fingers.

It’s possible for several joints to be affected at the same time. It’s not common to have gout in joints towards the centre of your body, such as the spine, shoulders or hips.

Gout attacks are especially common in joints at the ends of your legs and arms, such as in your fingers and toes. This is probably because these parts of the body are cooler, and low temperatures make it more likely for crystals to form.

Similar attacks can be caused by a condition called acute calcium pyrophosphate crystal arthritis. This is also known as acute CPP crystal arthritis, which used to be called ‘pseudogout’.

Tophi

Urate crystals can also collect outside of the joints and can be seen under the skin, forming small, firm lumps called tophi. You can sometimes see the white colour of the urate crystals under the skin.

The most common areas for tophi are:

• over the top of the toes
• back of the heel
• front of the knee
• backs of the fingers and wrists
• around the elbow
• the ears.

Tophi aren’t usually painful, but they can get in the way of normal daily activities. They can sometimes become inflamed, break down and leak pus-like fluid with gritty white material – these are the urate crystals.

Tophi can also grow within your joints and cause damage to your cartilage and bone. This can lead to more regular, daily pain when you use the affected joints.

Causes of gout

The buildup of uric acid in your blood from the breakdown of purines causes gout.

Certain conditions, such as blood and metabolism disorders or dehydration, make your body produce too much uric acid.

A kidney or thyroid problem, or an inherited disorder, can make it harder for your body to remove excess uric acid.

You’re more likely to get gout if you:

• are a middle-aged man or postmenopausal woman
• have parents, siblings, or other family members with gout
• eat too much purine-rich food, such as red meats, organ meats, and certain fish
• drink alcohol
• take medications such as diuretics and cyclosporine
• have a condition like high blood pressure, kidney disease, thyroid disease, diabetes, or sleep apnea

In some people with gout, diet is the cause. Find out which foods are especially high in gout-producing purines.

Risk factors

Family history

Even though your kidneys can be completely healthy, sometimes the genes you’ve inherited make it more likely that your kidneys don’t flush urate out as well as they should. This is the most common cause of primary gout, especially when several family members are affected, such as your parents or grandparents.

Being overweight

Gout is much more common in people who are overweight. The more overweight you are, the more urate your body produces, and this may be more than your kidneys can cope with.

Being overweight also makes it more likely that you’ll have:

• high blood pressure
• type 2 diabetes
• high cholesterol
• fats in your blood.

These conditions can all lower how much urate is filtered out by your kidneys.

Gender and age

Gout is about four times more common in men than women. It can affect men of any age, but the risk is greater as you get older.

Women rarely develop gout before the menopause. This is because the female hormone oestrogen increases how much urate is filtered out by the kidneys. But after the menopause, oestrogen levels go down and urate levels go up.

Taking certain medications

Some medications can reduce your kidneys’ ability to get rid of urate properly. These include diuretics, also known as water tablets, and several tablets for high blood pressure, including beta-blockers and ACE inhibitors.

Other conditions

Several different conditions are linked to raised urate levels. This could be because they affect the way the kidneys filter urate, or because they cause more urate to be produced in the first place.

For some conditions, the link with gout is less clear, and may be due to many different factors.

Common conditions associated with gout include:

• chronic kidney disease
• high cholesterol and fats in the blood
• high blood pressure
• type 2 diabetes
• osteoarthritis.

What can trigger a gout attack?

Several things can cause the crystals to shake loose into your joint cavity, triggering an attack. These include:

• a knock or injury to the joint
• an illness that may make you feverish
• having an operation
• having an unusually large meal, especially a fatty meal
• drinking too much alcohol
• dehydration
• starting urate lowering therapy, especially at a high dose, or not taking your treatment regularly each day.

• Gout medications are well tolerated by most people. However, like other medications, they have potential side effects.
• Allopurinol is well tolerated by most people, but in some people, it can cause an allergic rash. Very severe rashes rarely can occur after taking allopurinol, and any allergic type rashes that develop while a patient is taking allopurinol are taken seriously.
• Colchicine (Colcrys) can cause signs and symptoms such as nausea, diarrhea, and rarely muscle weakness and abnormal blood counts.
• Probenecid is generally well tolerated but should not be used in patients who have uric acid kidney stones, as it can worsen the kidney stones and potentially harm the kidneys in these patients.
• Febuxostat (Uloric) can cause liver abnormalities, nausea, and rash.
• NSAIDs can cause irritation of the stomach and ulcers in some cases. The liver and the kidneys are periodically monitored in patients taking NSAIDs over the long term.
• Krystexxa is administered as an intravenous infusion. Severe allergic reactions have been reported in a minority of people receiving Krystexxa.

Uric acid is formed when proteins in the food we eat, called purines, are broken down. Therefore, there has been a great deal of interest in dietary management of gout by avoiding high-purine (purine-rich) foods. However, a diet very low in purines is extremely difficult to follow, because purines are a natural part of many healthy foods. Even when a diet very low in purines is followed strictly, the uric acid level in the bloodstream is only slightly lowered.

The following dietary principles are important in the management of gout:

• Gout is associated with obesity, and significant weight loss can dramatically improve the management of gout. A calorie-reduced diet is helpful for weight loss.
• A diet low in saturated fat, with increased protein and replacement of refined carbohydrates (for example, sugar, white bread, potatoes) with complex carbohydrates (such as vegetables and whole grains) reduces the serum uric acid.
• Decreased consumption of seafood and red meat.
• The consumption of low-fat dairy products decreases the risk of gout.
• Drinking beer and liquor increase the risk of gout. However, drinking wine does not appear to increase the risk of gout.
• In one study, consumption of fresh cherries was associated with a 35% decreased risk of gout. Some people believe that black cherry juice or dried cherries have the same effect, but this has not been proven.
• Drinking beverages sweetened with sugar or high fructose corn syrup increases the risk of gout.