US Pharm. 2009;34(6):HS-7-HS-11.
Polymyalgia rheumatica (PMR) is an inflammatory rheumatic disease characterized by pain and stiffness in the neck, shoulders, and/or pelvic girdle.1,2 It primarily affects adults 50 years or older with an incidence of 100 per 100,000 and a peak onset in the seventh decade of life.3,4 Prevalence of PMR is reported to be highest among whites, people of northern European descent, and women.5-7 Although the etiology of PMR remains unclear, a genetic predisposition is believed to exist due to the presence of and link to an HLA-DR4 allele.2-4 Environmental factors, particularly infectious triggers, have also been associated with this disease.4,7 PMR possesses several distinct characteristics; however, symptoms may be similar to other autoimmune, infectious, endocrine, and malignant disorders.8 It is closely related to giant cell arteritis (GCA), also referred to as temporal arteritis, which is a chronic vasculitis of large and medium-size arteries. GCA occurs less frequently than PMR and typically involves inflammation of the temporal arteries and cranial branches leading to headache, scalp tenderness, and potential blindness.8,9
Clinical Presentation
PMR generally presents in relatively healthy older adults with a sudden onset of aches and pains in the proximal muscle groups. Initially, symptoms are unilateral; however, as the condition progresses, almost all patients report bilateral aches and pains.10 Areas commonly involved include the neck, shoulders, back, hips, and thighs. Fatigue, malaise, and a low-grade fever often accompany the aches and pains. Although muscles become tender, strength is usually preserved. Patients may also present with recent weight loss.11 Many self-treat with heat application and OTC analgesics until symptoms worsen and a decrease of activities of daily living results.
A thorough assessment of PMR for patients who present with the above symptoms includes a measurement of erythrocyte sedimentation rate (ESR). Normal ESR is dependent on age and is calculated for men by dividing their age by two and for women by adding 10 to their age and then dividing by two.11 An ESR greater than 40 to 50 mm/h is clinically indicative of PMR. In certain cases, ESR may be normal, mildly elevated, or even exceed levels of 100 mm/h.11-14 Other clinically supportive laboratory data in the diagnosis of PMR include elevations in C-reactive protein (CRP) and/or alkaline phosphate, as well as mild normocytic normochromic anemia.12 In PMR, serum creatine kinase is found to be normal, which helps to differentiate this condition from polymyositis (inflammation of muscles) and other myopathies.15
It should be noted that ESR may be elevated in many other conditions with presentations similar to those of PMR. Examples include malignancies, acute and chronic infections, thyroid disorders, depression, osteoarthritis, rheumatoid arthritis, myalgias, and polymyositis.4,12 It is recommended that all patients presenting with signs and symptoms consistent with PMR also be worked up for possible GCA, as well as be evaluated for visual disturbances, temporal or occipital headaches, and jaw or ear pain. Patients may complain of pain while chewing or tenderness when shampooing or combing their hair.16,17 Common clinical manifestations of PMR are presented in TABLE 1.
A number of researchers have proposed various clinical criteria for PMR; however, no standardization currently exists. Bird et al developed criteria that determined a probable diagnosis of PMR when any three or more of the following criteria are present with or without a clinical or pathologic abnormality of the temporal artery: age 65 or older; bilateral shoulder pain and/or stiffness; morning stiffness, bilateral tenderness of upper arms; depression and/or weight loss; duration of morning stiffness for more than 1 h; initial ESR greater than 40 mm/h; or onset of illness fewer than 2 weeks in duration.19
Patients should consult with a physician when these clinical signs and symptoms present. Pharmacists should refer patients to their primary care provider for further evaluation. A detailed history, physical examination, and laboratory evaluation are needed to make a proper diagnosis.
Management
There are no preventive measures recommended for PMR. Early identification of this condition and appropriate treatment are key in order to avoid the development of progressive debilitation. It is important to note that almost 20% of patients with PMR may present with a normal or mildly elevated ESR; therefore, treatment should be based on the signs and symptoms upon presentation.13,14
The mainstay of PMR treatment is corticosteroid therapy. Response to therapy is seen rather quickly, with reduction in the severity of myalgias noted only several hours after initiation of steroid treatment and resolution within 48 to 72 h.1,20 The dramatic and positive responses to corticosteroid therapy seen in patients with PMR have suggested that a trial of steroids may be administered as an unofficial diagnostic tool for PMR.2,21 If patients do not respond to the steroid therapy, diagnosis of PMR should be reconsidered and other etiologies should be sought.10
The drug of choice in PMR is prednisone, administered at low doses of 10 to 20 mg daily. Steroid therapy is continued until symptoms are controlled and ESR returns to normal, at which time tapering of the steroid should be initiated. Tapering should take place over several months and must be done slowly to prevent any relapses of PMR.20 The initial recommended taper is a reduction of 2.5 mg every 2 to 4 weeks until a dosage of 10 mg per day is achieved. Once a patient is receiving 10 mg per day, the tapering slows to a reduction of 1 mg every 2 to 4 weeks until 5 mg a day is achieved.20 The total duration of therapy is approximately 2 to 3 years.22,23 Relapse rates may be as high as 25%; relapses most frequently occur within the first 18 months of therapy or within 12 months after the discontinuation of treatment.24 Patients receiving steroid therapy for PMR are at a considerably high risk for drug-related complications. Long-term corticosteroid use increases the risk for infections, hyperglycemia, hypertension, impaired wound healing, cataracts, glaucoma, and osteoporosis.25 Patients should be monitored accordingly throughout their course of therapy.
Nonsteroidal anti-inflammatory drugs (NSAIDs) have also been reviewed for the treatment of PMR; however, data are lacking and conflicting. Certain sources caution against the use of NSAIDs due to their inferior efficacy in resolving symptoms and preventing relapses, as compared to corticosteroids.26,27 Other sources suggest that mild PMR may be successfully treated with a short course (2 to 3 weeks) of NSAID therapy. For those who do not respond adequately within this period of time, NSAID therapy should be discontinued and corticosteroids initiated.28
Immunosuppressant drugs, such as methotrexate and azathioprine, have been studied as corticosteroid-sparing agents in the treatment of PMR as well. Most studies conducted with methotrexate found that there were no significant increases in efficacy with methotrexate and corticosteroids when compared to corticosteroids alone; nor were there any steroid-sparing effects observed with methotrexate.29,30 However, methotrexate has shown some benefit in the treatment of corticosteroid-resistant PMR.31 There are little data on the steroid-sparing effects of azathioprine, although one study did show a significant steroid-sparing effect at 1 year, at which time patients already had considerable exposure to steroids.32
Pharmacist's Role
Pharmacists should be aware of the clinical manifestations and treatment options of PMR. It is a common disease in older adults; however, it may go undetected due to the nonspecific musculoskeletal complaints and generalized presenting symptoms. Pharmacists should refer a patient to his or her primary care provider when PMR is suspected, deterring the patient from self-treating of symptoms. Self-treatment may delay effective treatment and potentially worsen the disease, leading to further debilitation.
Once treatment is initiated, pharmacists should counsel their patients on the importance of taking their steroids properly and tapering doses as instructed. This will increase treatment success and decrease the chance of PMR relapse. Also, education should be provided regarding osteoporosis prevention. Ensuring proper calcium and vitamin D supplementation is essential. The National Osteoporosis Foundation recommends that adults 50 and older consume 1,200 mg of calcium and 800-1,000 IU of vitamin D daily.33 This may be achieved through either diet, supplementation, or a combination of both. Pharmacists play an essential role in evaluating the total daily intake of calcium and vitamin D and may provide recommendations on calcium-rich foods as well as supplementations. Calcium is more easily consumed through food sources; however, specific attention should be paid to the vitamin D intake, which is less easily obtained through natural sources. Recommending a bisphosphonate for the prevention of steroid-induced osteoporosis may also be appropriate in certain cases.34,35
Conclusion
PMR continues to be a complex condition that generally presents in older adults. It is important to be aware of the clinical manifestations of this inflammatory rheumatic disease in order to ensure proper treatment and prevention of complications. In addition, there are many opportunities for pharmacists to educate patients on drug therapies, potential side effects, and complications of PMR.
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