Polymyalgia rheumatica and and giant cell arteritis

Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA) are two related conditions in which the immune system attacks healthy tissue.

In PMR, the immune system causes the tissues of the joints to become inflamed, causing symptoms of muscle pain and stiffness

In GCA, the immune system makes the arteries inflamed, causing a range of symptoms including:

• headaches,
• jaw pain, and
• impaired vision, such as double vision or loss of vision.

Polymyalgia rheumatica (PMR) and giant cell arteritis (GCA)

Many experts believe that rather than being two separate conditions PMR and GCA are symptoms of a single, as yet unidentified, underlying health condition. This is because cases of PMR and GCA often develop at the same time in one person.

An estimated 40-60% of people with GCA will also have, or will develop, PMR. An estimated 15-20% of people with PMR will also have, or will develop, GCA.

The causes of both PMR and GCA are unknown. As with many autoimmune conditions (conditions where the immune system attacks healthy tissue), it is thought that a combination of genetic and environmental factors is responsible.

How common is polymyalgia rheumatica?

PMR is uncommon.

PMR is age-related. Almost all cases develop in adults who are 50 or over. The older a person gets, the higher their risk of developing PMR.

PMR is three times as common in women as in men. It is most common among white people, particularly those of Scandinavian descent.

How common is giant cell arteritis?

GCA is slightly less common than PMR, with an estimated seven new cases a year for every 100,000 people. GCA has the same risk factors as PMR, including age, ethnic group, sex and geographical location.

Outlook

The outlook for people with PMR is excellent. It responds very well to steroid medication and most people will notice a significant improvement in symptoms within a few days of treatment. To prevent a relapse, though, it is usually necessary to take steroid medication for up to two years.

The outlook for GCA depends on whether the condition is diagnosed and treated with steroids before loss of vision occurs. If it is, GCA will usually respond well to treatment and people with GCA are unlikely to have any serious after-effects.

If GCA isn't treated with steroids before any vision is lost, it is likely that the loss will be permanent.

Glossary

White blood cells

White blood cells are part of the blood. They help fight infection and disease.

Pain

Pain is an unpleasant physical or emotional feeling that your body produces as a warning that it has been damaged.

Bacteria

Bacteria are tiny, single-celled organisms that live in the body. Some can cause illness and disease and some others are good for you.

Joints

Joints are the connection points between two bones that allow movement.

Swelling

Inflammation is the body's response to infection, irritation or injury. It causes redness, swelling, pain and sometimes a feeling of heat in the affected area.