There are over 200 different forms of arthritis. When most people talk about arthritis they are talking about the most common kind which is called osteoarthritis.

What causes arthritis?

There is a common misconception that bad weather causes arthritis. Whist this is not the case, bad weather does cause the symptoms of arthritis to feel worse. Sufferers of osteoarthritis often complain of worsening aches and pains in the joints when cold damp weather is on the way.

What causes osteoarthritis?

Osteoarthritis is actually caused by the wear and tear of the joints; this is where one bone in the body meets another.

Rheumatoid Arthritis (RA) is another common form of the condition. It is caused by inflammation in and around the joint. Other types of arthritis like Ankylosing spondylitis are also caused by inflammation and are known as inflammatory arthritis.

Gout

Gout is a type of arthritis caused when uric acid builds up in blood and accumulates in the joints causing pain and inflammation. When gout is acute it is very painful and usually affects one joint only. Chronic gout is when there are repeated episodes of pain and inflammation, these may affect more than one joint. When you body has higher-than-normal levels of uric acid it causes gout. This may be because your body makes too much uric acid or you don’t get rid of uric acid quickly enough.

The exact cause of gout is unknown. Gout, like some other types of arthritis sometimes runs in families. It is more often diagnosed in men, in post menopausal women, and in both man and women who drink alcohol.

The condition may also develop in people with:

• Diabetes
• Kidney disease
• Obesity
• Sickle cell anemia and other anemias
• Leukemia and other blood cancers

The condition may occur after taking medicines that interfere with the removal of uric acid from the body.

Symptoms of gout

Symptoms of gout are usually limited to only one or two joints. The most commonly affected are big toe, ankle joints, or knees. The pain is throbbing, crushing, or excruciating and starts suddenly, and is often much worse at night. The joint feels warm and turns red. Gout causes joints to be tender (it hurts to lay even a sheet over it). Some people get a fever. Usually the first attack will go away in a few days, but the gout pain may return later. Subsequent attacks often last longer than the first. After a first attack, some people will have no symptoms of gout for a while but about half of patients will have another episode. Some people may develop chronic gout with tophi, lumps below the skin. Those with chronic gouty arthritis develop joint damage and loss of motion in the joints. They will have joint pain and other symptoms most of the time.

What causes gout?

Gout is also a type of arthritis known as chemical arthritis as it is caused by crystals forming inside the joint space.

What happens inside the joints?

Inside a joint, like a knee joint, there is a substance called cartilage which cushions the joint. When people develop osteoarthritis the cartilage is warn away causing the two bones within the joint to rub together.

Osteoarthritis can form in almost any joint inside the body. Common joints affected by arthritis, particularly in woman, are the small joints inside their hands. However, osteoarthritis can also be found in the knees and hips. It is also possible to suffer from osteoarthritis in a joint on one side of the body but not the other.

It is most likely that if anyone lives long enough they will develop arthritis. It is important to discuss any pains or aches in the joints with a doctor as it is only when the correct form of arthritis is diagnosed that appropriate treatment can be received.

Dr Carol Cooper MA, MB, BChir (Cantab), MRCP
Arthritis Expert, Imperial College Medical School

Dr Carol Cooper is climbing Sydney Harbour Bridge to raise money for Arthritis Care and hopes you'll check out her JustGiving page and sponsor her.