Info on PMR | Arthritis Information

Polymyalgia rheumatica is the name given to a pattern of aching and stiffness particularly around the upper arms and thighs, usually of sudden onset, occurring in the elderly in association with a high ESR. The symptoms appear to arise partly from muscle, but also from large joints and associated ligaments and fascia. Some cases have definite synovitis of shoulder, sternoclavicular, hip or other joints. Other cases have a more peripheral pattern with hand swelling difficult to distinguish from acute rheumatoid arthritis. A significant minority of cases also develop giant cell arteritis. The cranial arteries are most often involved, but the aortic arch and rarely lower limb vessels may be affected.

Muscle biopsy shows immune deposits around fascicles but no cell infiltration. Immune complexes are present in serum, which contain alternative pathway complement components. No unique autoantibodies have been found, but 40% of patients have antibodies to thyroid proteins and a minority have clinical thyroid disease.

Polymyalgia usually improves spontaneously after 2-5 years, during which time symptoms are usually controllable with low dose steroids.

The diagnosis of polymyalgia can often be strongly suspected, but certain differential diagnoses should always be considered and excluded. A screen for hypothyroidism and hepatic or renal disease, with an acid phosphatase for prostatic carcinoma in elderly males are essential. So is a full blood count to identify conditions such as leukaemia. As in rheumatoid arthritis, hepatic enzymes may be raised and there may be normocytic anaemia. The ESR is usually, but not always, very high and, if so, protein electrophoresis is also essential to exclude myeloma. A chest radiograph is probably worthwhile.

Treating with steroids is more likely to be the correct course if the patient is elderly, the onset is acute, the ESR is very high, and the initial response is dramatic. It is useful to start with as little as 10mg because larger doses will produce improvement in many other conditions, including depression. After steroids have been started the situation requires continual review. An underlying malignancy may disclose itself at any time. The clinical picture may drift towards rheumatoid arthritis. Giant cell arteritis may supervene. It may become clear that the problem was due to cervical spine osteophytes after all. It is usually possible to reduce the dose of steroid to 5mg or less within a few months. It is not always possible to withdraw completely. Many patients have residual symptoms. However, it is not essential to make the patient symptom free. If they say they are still a bit stiff, but nothing like as bad as at first, steroids should probably be stopped.

Some people use the ESR to judge the steroid requirement. This may help at times but treatment is for symptoms and symptoms can be used as the guide to need. If there is a fear of arteritis the doses have to be larger.

Other drugs may be useful in this condition. NSAI sometimes help symptoms sufficiently to obviate using steroids, but not very often. Azathioprine can be added as a steroid sparing agent if it is difficult to keep the dose low.

A proportion of patients will develop, or will have presented with giant cell arteritis, usually affecting cranial vessels. Presentations can include scalp pain, pain on chewing, loss of vision in one eye and stroke. These patients require 60mg of prednisolone. This can be reduced if both clinical features and the ESR have settled. The ESR should probably be maintained below 25, since arteritis produces no warning symptoms. If it difficult to reduce steroids azathioprine can be added.

Steroids reduce all features of inflammation by modification of transcription of a wide range of proteins. High dose steroids are toxic and are limited

to specialised indications, such as vasculitis. In rheumatoid arthritis doses from 2.5 to 5mg daily are arguably more useful and no more toxic than cyclo-oxygenase inhibitors. A dose of 7.5mg used for two years after presentation was found to be free of major problems. However, there is always a temptation to increase the dose, and toxicity is cumulative, with even mall doses being toxic over more than 5 years. As a yardstick 10mg daily is safe for 6 months, 5mg for 4 years and 2.5mg for ever (but is little more than physiological). Beyond this toxicity rises rapidly, particularly in terms of osteoporotic fracture. Starting a patient on prednisolone is a life long responsibility.

The use of steroids in rheumatic disease generally is more dependent on the time scale of treatment then the diagnosis. Steroids are used in conditions which are likely to remit after a period of weeks or months and remain in remission for most of the time. Because rheumatoid arthritis does not fulfil these criteria it is not a good target for steroids. Conversely, lupus and polymyalgia rheumatica, which remit, are appropriate. Even in lupus, because relapse is common and may be frequent, steroids are only used when the patient is seriously ill or at risk from vital organ damage.

Unwanted effects of steroids by mouth: Acne, hirsutes, osteoporosis, thin skin with bruising and tearing with minor injury to the leg, posterior subcapsular cataract, diabetes, hypertension, susceptibility to infection.