Among the vast amount of patients who suffer from pain those should be identified in whom the symptoms could be effectively relieved with low-dose glucocorticoids.
A patient with typical polymyalgia rheumatica that responds well to glucocorticoids can be treated in the primary care. Suspicion of giant cell arteritis (earlier temporal arteritis) Giant Cell (Temporal) Arteritis, atypical clinical features and non-satisfactory response to treatment are indications for a consultation in the specialized care.
In general
Polymyalgia rheumatica is a chronic inflammatory disease of unknown aetiology.
Muscular pain and stiffness as well as systemic symptoms characterize the clinical picture.
The incidence of polymyalgia rheumatica is approximately 500 cases per million people.
There is a female preponderance. The disease is encountered almost solely in patients over 50 years of age. Peak incidence is among 70-year-olds.
Symptoms
Symmetrical pain and stiffness in the neck, shoulders, upper arms, lumbar region and thighs for more than one month. The pain is accentuated during the night and in the morning and is associated with prolonged morning stiffness.
General symptoms: fatigue, weight loss, loss of appetite, fever, depression
The onset is usually fairly acute. The patient may be able to tell the exact day when the symptoms started.
Because of the association between polymyalgia rheumatica and giant cell arteritis it is important to recognize the clinical picture that includes headache, jaw claudication, tenderness of the scalp, visual disturbances and claudication in the extremities. These symptoms should trigger diagnostic exploration with giant cell arteritis Giant Cell (Temporal) Arteritis in mind.
Clinical signs
Painful restriction of movement of the shoulder and hip joints
No tender spots as in fibromyalgia, but there may be tenderness on palpation in the upper arms and thighs.
In some cases there may be arthritides of the wrists or fingers resembling rheumatoid arthritis. In elderly people, rheumatoid arthritis may have a polymyalgic onset.
Investigations
The following are necessary laboratory investigations in the diagnostic stage: ESR, CRP, basic blood count with platelet count.
For the differential diagnostics also other laboratory tests may be necessary; see sections Diagnosis and Differential diagnosis
Diagnosis
Diagnosis based on clinical findings is often sufficient: age over 50, typical clinical picture, increased ESR (> 40 mm/t) and rapid subjective response to predniso(lo)ne (12.5-25 mg/day) within 3 days.
ESR is a good screening test when polymyalgia rheumatica is suspected as the cause of musculoskeletal pain (cf. fibromyalgia Fibromyalgia).
Laboratory findings demonstrate the typical features of a generalized inflammation: in addition to increased ESR the findings include a marked increase of plasma CRP concentration, mild to moderate normocytic anaemia and thrombocytosis. Plasma alkaline phosphatase may be increased. Rheumatoid factor and anti-citrulline antibodies are usually negative. Creatine kinase concentration is normal (cf. polymyositis).
Ultrasonography of the shoulders or hips is a useful part of the initial investigations. It often reveals bursitis, tenosynovitis or synovitis. Soft tissue inflammation may also be visualized by MRI or PET scanning. The latter investigation may reveal subclinical inflammation in the walls of large arteries.
Temporal artery biopsy (video Temporal Artery Biopsy) is only indicated if symptoms or signs suggest the possibility of giant cell arteritis.
It is not considered necessary to try to exclude latent cancer in patients with typical polymyalgia rheumatica.
Differential diagnosis
A great number of conditions may resemble polymyalgia rheumatica.
Polymyalgia rheumatica is treated with low-dose glucocorticoids that typically eliminate or essentially relieve the symptoms within a few days.
The initial dose of prednisone or prednisolone is 12.5-25 mg/day. If the symptoms do not subside within 3-5 days the correctness of the diagnosis should be suspected. Larger glucocorticoid doses are seldom needed.
The initial dose is continued for 2 to 4 weeks. After that, the dose may be gradually tapered while monitoring symptoms and CRP (CRP is a more sensitive and rapidly-reacting parameter than ESR).
The predniso(lo)ne dose is initially tapered by 2.5 mg monthly, later more slowly. The maintenance dose ranges from 5 to 7.5 mg daily.
The duration of treatment is (6-)12-24 months. Some patients require glucocorticoid therapy for several years or it may be impossible to discontinue the medication.
Glucocorticoid therapy abolishes the symptoms but the duration of the disease is not reduced.
If the treatment is stopped too early and there is an activation of the disease, reinstitution of glucocorticoids at a higher dose will settle the symptoms anew.
If the response to predniso(lo)ne remains insufficient or if the drug is harmful (osteoporosis, diabetes), methotrexate or azathioprine may be combined to it.
Prophylaxis against osteoporosis is started concomitantly with the decision to start glucocorticoid treatment.
Since the patients are elderly and it is likely that the glucocorticoid therapy is needed for a lengthy period, it is in practice almost always necessary to start a bisphosphonate or some other specific anti-osteoporotic medication as well.
Discontinuation of the anti-osteoporotic medication may be considered when the glucocorticoid therapy ends.
Follow-up
The aim is to find the smallest dose of glucocorticoid that is still effective. The dose is defined individually in each patient by monitoring the inflammatory activity of the disease.
During glucocorticoid therapy, follow-up visits are recommended at 4-8 week intervals in the beginning and later at 8-12 week intervals.
In addition to the clinical assessment, CRP provides a good estimate regarding the inflammatory activity of the disease.
During follow-up visits, attention should also be placed on possible adverse effects of glucocorticoid therapy (see Pharmacological Glucocorticoid Treatment) as well as on a possible associated disease.
Laboratory tests to be monitored include: ESR, CRP, basic blood count with platelet count, and plasma creatinine, glucose and electrolytes.
Prognosis
The disease has a tendency to relapse. The patient is usually able to identify the symptoms and readily seek medical advice.
References
Dejaco C, Singh YP, Perel P ym. 2015 Recommendations for the management of polymyalgia rheumatica: a European League Against Rheumatism/American College of Rheumatology collaborative initiative. Ann Rheum Dis 2015;74(10):1799-807. [PubMed]