POLYMYALGIA RHEUMATICA and TEMPORAL ARTERITIS

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Polymyalgia Rheumatica and Temporal Arteritis are closely related conditions occurring usually after age 50, and more commonly in women. The conditions occur predominantly in caucasions and are of unknown cause, although there is a suggestion that they may be triggered by certain viral infections (parainfluenza 1, mycoplasma, chlamydia and parvovirus).

Polymyalgia Rheumatica

This is the more common condition and is characterised by quite severe muscle and tendon pain and morning stiffness affecting the shoulder and hip girdles and the neck muscles and tendons. Stiffness after inactivity is common and general symptoms of un-wellness, weakness, fatigue, depression, weight loss, night sweats and fevers occur in a third of patients.

There is no specific test for polymyalgia rheumatica, but the ESR and C Reactive Protein (CRP), which are markers of inflammation, are usually significantly elevated - but not in all cases.
Other diseases, including rheumatoid arthritis, muscle inflammation, hypothyroidism, myeloma and other malignancies may mimic polymyalgia rheumatica and need to be excluded.
Treatment with steroids ( prednisolone at a starting dose around 20mg) is usually associated with a dramatic improvement in symptoms within 1 to 2 days - this dramatic response is almost diagnostic of the condition.

Treatment is usually required for 1 to 2 years, but may be required for much longer. The steroid dose is gradually reduced to the lowest level which controls the symptoms - monitoring the ESR and CRP is also useful in  reflecting disease activity.

Long term steroid therapy may result in a reduction in bone density and impaired glucose tolerance - these need to be monitored as does the cholesterol level.
Weight control, fitness maintenance and calcium and vitamin D supplementation will help prevent these unwanted effects.

Should symptoms not respond to steroid treatment, an alternate diagnosis needs to be explored.

Occasionally patients with polymyalgia rheumatica will develop temporal arteritis - should any of the following symptoms develop urgent medical review is required :
- unilateral vision disturbance - especially loss of sight in an eye, which may be temporary (amaurosis fugax), but also double vision or a visual field defect
- severe persistent unilateral headache often associated with scalp tenderness
- pain in the jaw or tongue while chewing

Temporal Arteritis

Temporal Arteritis is much less common, but potentially very serious. It tends to occur in an older age group. Around 40% of those developing temporal arteritis have pre-existing polymyalgia rheumatica.

Temporal Arteritis involves an inflammation of arteries, particularly the carotid arteries and their branches. It is particularly important because the blood supply to the eye can be affected resulting in blindness.
The typical symptoms are the new onset of severe unilateral headache often associated with scalp tenderness on the same side. The artery in the temple is often swollen and tender to touch.
Other symptoms may include :
- visual changes in the eye on the affected side - these may be temporary blindness (amaurosis fugax), blurred or darkening of vision, double vision, visual field defect or a drooping eye lid
- pain in the jaw or tongue when chewing (claudication)
These symptoms are due to obstruction of blood flow through the inflamed arteries.
Night sweats, fevers, general un-wellness etc often accompany these other more specific symptoms.

Diagnosis is similar to polymyalgia rheumatica with a raised ESR and C Reactive Protein - biopsy of the temporal artery is required to confirm the diagnosis.

*Because of the risk of permanent blindness, high dose steroid (prednisolone 60 mg) should be commenced when the diagnosis is suspected (and before any test results are obtained). Temporal artery biopsy should be performed as soon as possible.

Long term monitoring with ESR and CRP and steroid dose tapering is similar to polymyalgia rheumatica, but the length of treatment is considerably longer.
The addition of anti-platelet treatment (low dose aspirin or clopidrogel) has been shown to significantly reduce the complications of temporal arteritis - however if anti-platelet medication + steroids are used, peptic ulcer preventive medication should also be added.

Other agents including methotrexate, cyclophosphamide or azothioprine are sometimes added to minimise the long term steroid dose required to suppress the disease. Measures to minimise the long term adverse effects of steroids (as described for polymyalgia rheumatica) should be implemented.

Occasionally the inflammation of temporal arteritis can also affect the thoracic aorta and result in a thoracic aortic aneurysm - this complication would not normally develop for around 10 years after the onset of the illness - there is a suggestion that a chest xray every year or two may be useful in early detection of an aneurysm.
 

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