Polymyalgia rheumatica (PMR) is one of the most common inflammatory rheumatic diseases in patients older than 50; the average age at diagnosis is 72.1 PMR is also one of the frequent indications for long-term corticosteroid therapy in community settings.2
The prevalence rate of PMR is about 700 per 100,000 people older than 50.1 It is two to three times more common in women than men,1 and it occurs most often in white people and people of European descent.3 PMR is a condition that may be overlooked because it presents similarly to common age-related complaints, including osteoarthritis.4
Definition and Pathophysiology
PMR is characterized by morning pain and stiffness of the neck, shoulder and pelvic girdle areas. Fever, malaise, depression and weight loss are also common.5 Symptoms usually occur bilaterally. The onset of PMR is acute, but it is usually diagnosed after symptoms have been present for weeks or months, most likely due to patient or provider disregard of symptoms or to misdiagnosis.3
The cause of PMR is not known, but it appears to be related to synovitis and bursitis of joints and extra-articular synovial structures.6 Synovitis in PMR is characterized by macrophages and T lymphocytes in the synovial membranes of involved joints.6 Inflammatory cytokines are produced by the activation of macrophages, and they cause the systemic manifestations of PMR.6 Several studies have attempted to demonstrate environmental, genetic and infectious (viral) etiologies. However, pathological findings are difficult to identify in all patients.
The symptoms of PMR typically present in the neck, shoulder and hips. Stiffness is often the predominant complaint.3 The pain usually radiates distally, and it is most severe with movement.6 The physical examination for a patient with PMR demonstrates painful restriction of active and passive movement of involved joints. Patients may have trouble sleeping, combing their hair, putting on a coat, or rising from a chair.5 Muscle strength is usually normal, but some patients report subjective muscle weakness. Systemic signs such as low-grade fever, depression, fatigue, anorexia and weight loss can occur in up to 40% of patients.6
Less commonly, patients may have distal musculoskeletal symptoms such as unilateral swelling of the knees and wrists, pitting edema and carpal tunnel syndrome.5,6 All of these symptoms may increase in frequency and severity at any time, and they may seem to resolve for a period of time before returning.
Lab studies may show elevated erythrocyte sedimentation rate (ESR) over 40 mm/hour, elevated C-reactive protein (CRP) over 5 mg/L, and normocytic anemia. However, 7% to 20% of patients with PMR have normal ESR values.6 Serologic tests such as antinuclear antibodies and rheumatoid factor are typically negative.1 MRI and ultrasonography are sometimes used to demonstrate synovitis and bursitis of affected joints.
Ultrasonographic evidence of bilateral shoulder or pelvic girdle bursitis can help confirm a diagnosis of PMR in the absence of elevated lab values.6 Plain radiographs are unnecessary except when used to rule out another diagnosis involving the joints.1 Positron emission tomography has no proven clinical value in the diagnosis of PMR, but it has been a recent focus of investigations examining underlying vascular involvement.1
In about 10% to 30% of PMR cases, giant cell arteritis (GCA) is also diagnosed. It may represent a different manifestation of a shared disease process.1,2 GCA is a severe and potentially life-threatening illness that should be ruled out in all patients with PMR. GCA, also called temporal arteritis, involves branches of the proximal aorta. It is characterized by headache, unilateral scalp tenderness, diplopia and jaw claudication. The temporal artery may be enlarged or tender. If left untreated, GCA usually leads to blindness due to ischemic optic neuropathy and death secondary to aortic dissection. In a patient with PMR, GCA can develop at any time.1,2
Diagnosis of PMR can be difficult due to the wide range of clinical manifestations and the possibility of atypical presentations. Table 1 lists the most common differential diagnoses and how to distinguish each from PMR. Most patients have bilateral proximal joint symptoms, but they may also have unilateral distal symptoms such as knee or wrist edema.
Click to view larger graphic.
In 2012, the American College of Rheumatology published the first classification criteria for PMR.7 According to these criteria, patients 50 and older can be classified as having PMR if they meet all of the following conditions:
• new bilateral shoulder pain (onset less than 12 weeks prior)
• morning stiffness lasting at least 45 minutes
• high levels of inflammation measured by protein in blood and ESR
• new onset hip pain
• absence of swelling in the small joints of hands and feet
• negative blood tests for rheumatoid arthritis.
Ultrasound findings of abnormalities in one shoulder and one hip improve the specificity of the criteria.7
GCA should be ruled out by way of temporal artery biopsy, especially when the patient has a fever of at least 39°C or does not respond to corticosteroid therapy.1
Because the list of differential diagnoses contains some serious illnesses (e.g., cancer and GCA), it is important to know when to refer a patient to a specialist. Typically, referral should be made to a rheumatology clinician. In general, refer a patient in the following circumstances:1,2
• age younger than 60 (some recommendations state younger than 50)
• when the illness does not cause shoulder pain or stiffness
• when the predominant feature is systemic in nature (i.e., weight loss, neurological signs)
• when the response to corticosteroids is incomplete or nonexistent.
In addition, refer patients who do not demonstrate a decrease in ESR and CRP after treatment begins.
Oral corticosteroid therapy is the standard treatment for PMR, usually for several months to a few years. Despite a general consensus about treatment, there is no universally accepted approach to initial corticosteroid dosing, maintenance therapy or dose reduction.8 The American College of Rheumatology classification criteria for diagnosing PMR may help evaluate treatment regimens by ensuring that these patients actually have the same condition.7 Typically, a greater than 70% resolution of the aching and stiffness occurs within 1 week, followed by normalization of ESR and CRP at 4 weeks.2 The dose can usually be tapered after 2 to 4 weeks of treatment, but symptom flares are common as the steroid is decreased. Table 2 provides examples of therapy regimens.
Click to view larger graphic.
To avoid relapse, keep the initial prednisone dose as low as possible and discontinue slowly.6 Corticosteroids may be stopped when clinical symptoms subside, regardless of ESR and CRP values.2 NSAIDs can be used throughout corticosteroid treatment as adjunctive therapy, but their use will increase GI risk.
Adverse effects of corticosteroids surface in 50% to 76% of patients with PMR.3,6 For milder cases, intramuscular steroid therapy can be used and may reduce the risk for steroid-related complications.2 Since PMR surfaces later in life, medications to protect the bone and stomach should be prescribed with corticosteroids. Patients with diabetes typically require adjustments to hyperglycemic agents. In addition, ongoing monitoring for symptoms of GCA is necessary.
Methotrexate and TNF-blocking agents such as infliximab have been proposed as treatments for PMR, but studies have produced conflicting results about their effectiveness.6
The patient with PMR should experience a dramatic improvement in symptoms within 72 hours of corticosteroid induction.4,6 ESR and CRP, if elevated at diagnosis, should return to within normal limits after 1 to 2 months of corticosteroid treatment.4 If PMR symptoms are resistant to corticosteroid therapy, reconsider other underlying illnesses and make a referral.5,8
Physical therapy can be useful for patients with longstanding PMR who have experienced loss of function, but it may not be necessary for all patients.
Follow-up is necessary 1 to 3 weeks after the commencement of corticosteroids and every 1 to 3 months thereafter, with extra visits for relapses or adverse events.2 Clinical symptoms and response to treatment, steroid-related side effects, changes in presenting features, complete blood count, ESR and blood glucose should be checked at every follow-up visit.2 Adverse effects from steroid therapy - for which all patients with PMR should be screened - include osteoporosis, weight gain, hyperglycemia, hypertension, immunosuppression, hyperlipidemia, peptic ulcers, depression, skin fragility, glaucoma and cataracts.
Recent studies have reported a relapse rate as high as 50% in patients with diagnosed PMR.6 The variation in relapse rates is most likely due to a combination of patient adherence variability and differences in prescribed corticosteroid doses and durations. If the clinical features return or do not respond to treatment with corticosteroids, an increase in steroid therapy, followed by a slower taper, is likely needed. If this scenario occurs, refer the patient to a specialist.
No mortality increase has been associated with PMR itself, but every effort must be made to control the side effects of corticosteroid therapy.8 Generally, PMR is self-limiting over months to years.
Recommendations for Practice
Nurse practitioners and physician assistants, particularly those in the primary care setting, need to be aware of PMR in order to correctly distinguish it from other diseases. Patients with PMR can experience marked pain and limitation in movement, as well as general malaise and depression. Their symptoms should be taken seriously and treated appropriately. The diagnosis of PMR demonstrates the usefulness of a thorough history.4
Because PMR can have similar symptomatology to other diseases, patient report of symptoms and response to therapy is imperative. NPs and PAs also should have knowledge base to refer a static or worsening patient to a rheumatology clinician.
1. Hunder G. Clinical manifestations and diagnosis of polymyalgia rheumatica. UpToDate. http://www.uptodate.com/contents/clinical-manifestations-and-diagnosis-of-polymyalgia-rheumatica
2. Bhaskar D. Concise guidance: diagnosis and management of polymyalgia rheumatica. Clin Med. 2010;10(3):270-274.
3. Whittle SL. et al. Steroid sparing drug treatments for polymyalgia rheumatica (protocol). Cochrane Database Syst Rev. 2009;1:CD005325.
4. Terrazas D, Schumann L. Managing polymyalgia rheumatica and giant cell arteritis in the primary care setting. J Am Acad Nurse Pract. 1997;9(6):289-292.
5. McPhee S, Papadakis M. Musculoskeletal and Immunologic Disorders. In: Current Medical Diagnosis and Treatment 2010. 49th ed. New York, NY: McGraw-Hill; 2010: 755-767.
6. Salvarani C, et al. Polymyalgia rheumatica and giant-cell arteritis. Lancet. 2008;372(9634):234-245.
7. Dasgupta B, et al. 2012 provisional classification criteria for polymyalgia rheumatica: a European League Against Rheumatism/American College of Rheumatology collaborative initiative. Arthritis Rheum. 2012;71(4):484-92.
8. Hunder G. Treatment of polymyalgia rheumatica. UpToDate. http://www.uptodate.com/contents/treatment-of-polymyalgia-rheumatica
9. Hernandez-Rodriguez J, et al. Treatment of polymyalgia rheumatica: a systematic review. Arch Intern Med. 2009;169(20):1839-1850.
Rebecca Flora is an adult nurse practitioner at St. Elizabeth Regional Diabetes Center in Covington, Ky. She has completed a disclosure statement and reports no relationships related to this article.