What is polymyalgia rheumatica?

Polymyalgia rheumatica (PMR) is the name given to a condition which results in severe stiffness and pain in the muscles of the shoulders, neck, spine, buttocks and thighs. The name 'polymyalgia rheumatica' (PMR) simply means rheumatic type pains in many muscles.

The muscle pain and stiffness is most often at its worse in the morning and tends to wear off as the day goes on. The forearms, hand, calves and feet are usually spared.

In addition to the muscular complaints, people with PMR usually experience other symptoms. These include weariness and loss of energy, poor appetite, night sweats and fevers, weight loss and depression. These complaints are often present at the beginning of the illness and in some cases are worse than the actual muscle pain.

PMR is a condition which affects older people - almost always occurring in people over 50 years of age. It is a bit more common in women and is said to be more frequent in pale-skinned people, although it is not unknown in Maori.

Often the onset is dramatic. A previously fit person goes to bed in good health and awakes to find that he or she is 'cast' in bed by the severe muscle stiffness and pain in the muscles. In other cases the onset is more gradual. It may start with some stiffness in one group of muscles (eg the shoulders) and over the next few weeks spread to involve the back, buttocks and thighs. If it is not treated, the severity and site of the symptoms may vary over the months.

At its most severe, PMR is very disabling. Because it is at its worst in the morning, getting out of bed and dressing are particularly painful and time consuming. Rising from chairs, walking and other tasks, which involve the shoulders and thighs, are difficult.

It is not unusual to find tasks that are impossible in the morning can be done in the afternoon when the stiffness has worn off. The loss of energy and depression can make taking part in life an effort. People with PMR sometimes find that they stop going out and that their social lives become restricted.

What causes PMR?

The cause is not known at present. The muscles themselves show no obvious abnormality when examined under the microscope. There is often minor inflammation of the joints but this does not seem bad enough to account for the very severe symptoms.

The occurrence of weight loss, fevers and fatigue with the abnormal blood tests [see below under 'How is PMR diagnosed?'] means it is a disease of the whole body rather than just muscles. A clue to its cause must lie in the fact that it only affects people who are in their 50s or older.

Some cases appear to start after a 'flu' like illness. It may be that a virus triggers off an alteration in the way the body's defence mechanism works and this is responsible for the continuing complaints.

Is PMR linked with other health problems?

In most people with PMR the complaints remain localised to the muscles. However, experience has shown that a few people with PMR eventually develop a form of rheumatoid arthritis.

We also know that some (we are not sure how many) people with PMR also have a condition involving the blood vessels called 'temporal arteritis' or 'giant cell arteritis'.

In giant cell arteritis (GCA) abnormal cells called giant cells are seen in inflamed arteries in the side of the scalp (temporal area). This condition also affects people over the age of 50 and, like PMR, is associated with complaints like loss of energy, fever and weight loss.

In GCA, small and medium sized arteries often become inflamed. This means they are often sore to touch and swollen. The arteries of the head, excluding those of the brain, are most frequently affected. When this happens, headaches, pain in the jaw or tenderness of the scalp results.

The severity and site of the headaches vary from person to person and some cases have no complaints in the head at all.

The major concern about GCA is that is sometimes affects the blood vessels to the eye and so can cause blindness. While this occasionally comes out of the blue, it is often preceded by brief spells of visual blurring or double vision. GCA very occasionally may result in stroke. However these serious effects are almost completely preventable by treatment with prednisone [see below under 'What is the treatment for PMR?'].

People with PMR may develop signs of GCA later in the course of their illness; people with GCA may develop PMR; and in some cases both conditions may come on at the same time, however most people with PMR do not develop GCA.

How is PMR diagnosed?

Unfortunately, there is no test that tells us that a person has or does not have PMR. The diagnosis is made by physical examination and the results of a simple blood test which measures erythrocyte sedimentation rate (ESR). The ESR is raised in a number of other conditions but it is usually very high in PMR. People with PMR often also have a mild anaemia.

If PMR occurs suddenly it is easy to diagnose because its symptoms are so distinct. It is much more difficult to diagnose when it creeps up over a couple of months.

Many elderly people experience aches and pains from a variety of causes and it is easy for both doctor and patient to put down PMR to 'old age, worry or rheumatism'. The symptoms of loss of energy, fevers and weight loss may suggest other illnesses like cancer or infection and the depression of PMR can be mistaken for a mental illness.

Accurate reporting of symptoms is very important for the doctor to make an early diagnosis.

What is the treatment for PMR?

The treatment of PMR is with long-term, low-dose corticosteroid tablets (usually prednisone). GCA is also treated with prednisone, although larger doses are sometimes necessary to control it.

Corticosteroids are hormones that are normally produced by the body's adrenal glands. They are called steroids or cortisone and are an essential part of the body's normal working system. These are quite different from other types of steroids such as anabolic steroids (which some athletes take illegally for enhancing muscle strength).

Corticosteroids do have side effects, which become more obvious with increased doses. The treatment for PMR only requires a low-dose to be taken so serious side-effects are uncommon. However, most people notice a fullness of the face, thinning of skin, easier bruising, and a tendency to put on weight.

Long term side effects can include thinning of the bones (osteoporosis) which can cause serious disability. Keeping the dose to the smallest possible, reduces this risk.

How is prednisone taken?

It is usual to take a higher dose to start with, when a rapid response is noticed. The initial dose will be continued for between two and eight weeks, and reductions after that are tailored to the individual. By reducing the initial dose gradually (sometimes at a rate of only 1mg every two to four weeks) the response is maintained and the return of pain and stiffness prevented.

If, during the reduction of prednisone, you develop headaches or alterations to vision, report this to the doctor straightaway in case it is due to the development of GCA.

Prednisone must not be stopped suddenly, because it damps down the body's own corticosteroid production and the adrenal glands might not be able to produce enough of this very important hormone on their own. Extra corticosteroids are needed at times of physical stress, like surgery or dental operations, other illnesses or accidents. You must tell other doctors and the dentist you are taking this medication.

Other medications

Non steroidal anti-inflammatory drugs (NSAIDs)
A night-time dose of a NSAID such as aspirin or ibuprofen may be useful to relieve mild symptoms of PMR, but does not provide as effective relief of symptoms as corticosteroids.

Disease modifying anti-rheumatic drugs (DMARDs)
Azathioprine or methotrexate has sometimes been used to reduce the amount of corticosteroid required in people taking high doses of corticosteroid.

Other treatments

Rest is important in the active phase and appropriate amounts of exercise may be increased once the stiffness starts to resolve. Physiotherapy is useful to help reduce pain and to avoid muscle wasting in severe cases.

What is the outlook?

For most people the natural course of the illness is for it to last somewhere between two and four years, before it eventually disappears. Many people will withdraw the use of prednisone within two years while others may require a very low dose for up to 10 years. One of the difficulties in telling if the illness has gone away completely is that the taking of prednisone must be discontinued. After two years it is considered feasible to stop therapy. If the symptoms return, then the use of prednisone will also return.

Polymyalgia rheumatica, unlike most forms of arthritis, does not cause increasing disability and deformity. The pain and stiffness is easily controlled with prednisone, and most people rapidly recover and return to their previous level of social and physical activity. The price to pay is the need to take a drug with some side effects until the illness becomes inactive with time.

Glossary

Arteritis - inflammation of the arteries - the tubes which carry oxygenated blood around our bodies.

Original material supplied by Arthritis New Zealand. Reviewed by everybody, July 2005.