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Polymyalgia Rheumatica

Polymyalgia rheumatica is a clinical syndrome that consists of by muscle aching and stiffness, without weakness, that involves the neck and shoulder girdle and pelvic girdle. The disorder usually affects persons over the age of 50 years. The diagnosis is based upon careful clinical assessment, and the symptoms are controlled rapidly and dramatically with low-dose corticosteroid treatment. Polymyalgia rheumatica can be an important clue to the existence of serious Polymyalgia Rheumatica.

Epidemiology

The average annual incidence for persons age 50 years and older is  50 cases/100,000. In the northern

Polymyalgia rheumatica clearly increases as the population ages. After the age of 80 years, the annual incidence was 78/100,000 in Goteborg and 97/100,000 in Olmsted County. Occurrence in women is about twice that in men.

Etiology

Genetic predisposition, infection, and immunological abnormalities appear to contribute to the etiology of polymyalgia rheumatica. The increased occurrence of polymyalgia rheumatica in people of northern European descent.

Pathophysiology

Epidemiologic data suggest that an appropriate genetic background contributes to development of polymyalgia rheumatica, and an infectious agent may trigger aberrant immune responses in a susceptible individual. The disease is characterized by striking muscle stiffness and pain, and muscles may display electromyographic abnormalities (fibrillation potentials, complex repetitive discharges) that improve after treatment with corticosteroids.

Clinical Features

The classic symptoms of polymyalgia rheumatica are muscle pain and stiffness, and these symptoms often form the basis of the chief complaint. The shoulder girdle is commonly the first area to become symptomatic, and pain is also experienced in the neck, upper back, upper arms, lower back, and hip girdle. The pain is typically severe, aching in nature, and bilateral. Pain is accentuated by movement of the joints, but the pain is not localized to the joints. The symptoms appear to arise in muscles, tendinous attachments.

Patients have prominent stiffness, resembling that found in rheumatoid arthritis. The stiffness is present in the morning, tends to wear off with movement, and recurs later in the day if the patient is inactive. The pain and stiffness may occur so abruptly that the patient remembers the date and hour of onset, or the onset may be gradual.

Constitutional symptoms that may be associated with polymyalgia rheumatica include malaise, fatigue, weight loss, and depression. Low-grade fever has been reported in polymyalgia rheumatica, but high spiking fever suggests underlying infection or giant cell arteritis.

Patients are limited functionally due to the pain and stiffness and may describe difficulties in acts that require use of the proximal musculature (brushing the hair or teeth, rising from the supine or sitting position). It should be emphasized, however, that the muscles are not truly weak.



Table 2. Diagnostic Criteria for Polymyalgia Rheumatica
• Bilateral shoulder pain and stiffness

• Onset of illness within two weeks

• Initial ESR higher than 40 mm/hour

• Morning stiffness exceeding one hour

• Age older than 65 years

• Depression and/or loss of weight

• Bilateral upper arm tenderness

Any three criteria discriminated between polymyalgia rheumatica and other conditions with sensitivity of 92% and specificity of 80%.


Adapted from Cimmino MA, Salvarani C. Polymyalgia rheumatica and giant cell arteritis. Balliere's Clin Rheumatol 1995;9:515-527 and based upon data in Bird HA, et al. An evaluation of criteria for polymyalgia rheumatica. Ann Rheum Dis 1979;38:434-439.

Therapy of Polymyalgia Rheumatica

The original series of patients reported by Barber included two patients who responded to phenylbutazone and three patients who had spontaneous remission. No patients received corticosteroids. Some patients have responded to NSAIDs. Chuang described 96 patients with polymyalgia rheumatica who were identified in a 10-year period in

There may be a role for NSAID treatment in selected patients with mild polymyalgia rheumatica, but many clinicians believe that low-dose prednisone is the treatment of choice. NSAID treatment often fails. In about two-thirds of individuals who receive aspirin or other NSAIDs initially, it is necessary to switch to corticosteroids.

A starting dose of 5-20 mg of prednisone a day is usually effective. Occasionally, a dose of 25 mg is required. Behn examined the prospective course of treated polymyalgia rheumatica. The corticosteroid dose was regulated.

Patients should remain on the starting dose of prednisone for a minimum of four weeks. The rate of dose taper is guided by the clinical response. Resolution of symptoms is more important than reduction in the ESR.

Patients whose disease is not controlled, or who have significant corticosteroid side effects, should be considered for treatment with a steroid-sparing drug. In one series, 65% of polymyalgia rheumatica patients treated.