Polymyalgia Rheumatica

 

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Original Editors - Nicki Spencer from Bellarmine University's Pathophysiology of Complex Patient Problems project.

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Prevalence

     In persons over the age of 50, PMR has a prevalence of approximately 700 per 100,00. Approximately 4 in 10,000 adults over the age of 60 develop PMR each year.       

    

Characteristics/Clinical Presentation

     The onset of PMR is very sudden. Individuals can usually remember the exact time and day that they began experiencing symptoms. Individuals often wake up one morning with extreme stiffness and soreness for no apparent reason.      This disorder generally manifests itself in the muscles of the neck, shoulder girdle, and pelvic girdle. The pain and stiffness is often symmetric and bilateral. Synovitis and bursitis of the shoulder and hip are typically what causes the patient's pain. Other signs and symptoms that can be seen include:

• stiffness after rising in the morning or after resting
• weakness
• fatigue
• malaise
• low-grade fever
• sweats
• headache
• weight loss
• depression  
• vision changes     

     Three primary risk factors that are associated with PMR are age, female gender, and race. This disease rarely occurs in individuals younger than 50 and most occur in individuals over the age of 70. Women are affected twice as much as men. PMR is more commonly seen in Caucasian women than women of any other ethnicity.

Associated Co-morbidities

Giant Cell Arteritis
     Giant cell arteritis (GCA) is a condition that produces inflammation in the arteries.  Approximately 1 in 20 people who are being treated for PMR, and about 7 in 20 with untreated PMR, develop GCA. The most common arteries affected are the temporal arteries.  Temporal arteritis is an extremely serious condition and requires immediate medical attention.  If left untreated, it could result in blindness.

  Symptoms include:

• headache or tenderness on one side of the head
• scalp tenderness
• pain in the jaw when chewing, which eases quickly when the jaw is rested
• tongue or throat pain
• sudden loss of vision or any other sudden visual problem in one eye
• weakness
• numbness
• deafness

Medications

     Corticosteroids

     If PMR is suspected to be the probable diagnosis for a patient, then a trial of low-dose corticosteroids (usually prednisone) is given. The response to corticosteroids is usually dramatic, and patients may report relief in symptoms after one dose. If symptoms are not better within 2-3 weeks of beginning the corticosteroid treatment, it is unlikely that the individual actually has PMR and more testing should be performed to find an appropriate diagnosis.

     If the patient has a favorable response to corticosteroids, they will continue to take a maintenance dosage for approximately 6 months to 2 years. This maintenance dosage can help control the pain and stiffness associated with PMR. Over that time period, the dosage is gradually decreased until it is no longer needed. Complete clinical remission may take up to 5 years to occur.

     Methotrexate     

     Methotrexate may be used to reduce the corticosteroid requirements of PMR.  There have been mixed results in different studies with the use of methotrexate.

Diagnostic Tests/Lab Tests/Lab Values

     PMR is a diagnosis of exclusion. There are no definitive diagnostic tests to identify PMR. Physicians will typically perform a physical exam, order blood tests, and perform imaging studies to determine if the patient’s symptoms are due to some other disorder. In some cases, an ultrasound or MRI may reveal large joint effusions and signs of bursitis or tendovagnitis in the shoulders and hips of patients with PMR. Some clinicians use an erythrocyte sedimentation rate (ESR) of higher than 30 or 40 mm/hr as diagnostic criteria; however, there have been reports of individuals diagnosed with PMR having an ESR of normal or only slightly higher than normal so this may not be an appropriate criteria.       

     There are also two sets of diagnostic criteria that have been created for PMR. The Bird/Wood criteria includes:

• Bilateral shoulder stiffness
• Duration onset < 2 weeks
• Initial ESR > 40 mm/hour
• Stiffness > 60 minutes
• Age > 65 years
• Depression and/or weight loss
• Bilateral upper arm tenderness     

     If any 3 or more of the above criteria, or greater than 1 criteria and a clinical abnormality of the temporal artery, are present in a patient then PMR is probable.  Definite PMR is characterized by probable PMR that has a positive response to corticosteroid therapy.     

     The Hunder criteria for the diagnosis of PMR includes: 

• Patient age > 50 years
• Bilateral aching and tenderness for > 1 month of neck or torso, shoulders or upper arms, and hips or thighs
• ESR > 40 mm/hour
• Exclusion of other diagnoses     

     All the above Hunder criteria must be present to have a diagnosis of definite PMR.     

     Both of the above criteria have been found to have a sensitivity of >90%.     

     If the patient also has GCA associated with their PMR, MRI angiography and positron emission tomography (PET) can identify possible vessels involved and monitor the disease course.

Etiology/Causes

     There is no clear cause for PMR; however, research has begun to suggest that it may occur due to a combination of environmental and genetic factors.

     Certain characteristics of PMR suggest that an infectious disease could be an environmental factor. It has a very sudden onset and new cases occur in cycles, which could indicate an infection as the source. Attention has been focused on Chlamydia, Mycoplasma, parainfluenza virus or parovirus B19 as possible infections responsible for PMR. 

     Inheritance of the disorder has been suggested due to findings in some genetic studies and a pattern seen in family histories. The gene(s) that could be responsible for PMR have not been definitively identified. The HLA-DRB104 and HLA-DRB01 alleles have both been found to have a possible link to PMR and GCA.

Systemic Involvement

     The systemic involvement of PMR is stated above in the Characteristics/Clinical Presentations and Co-Morbidities sections.  

Medical Management (current best evidence)

     As stated above in the Medications section, PMR is generally treated with a long course of corticosteroids.  Depending on the facility, the course of treatment will differ.  There is no consensus on the initial dosage and subsequent tapering of corticosteroids. Some suggest an initial dose of 15-20 mg/day of prednisone and then a slow tapering over several weeks or months to find a maintenance dosage.

     If the patient also has GCA, then the initial dose of prednisone is much higher (usually 1 mg/kg of body weight). GCA in the temporal artery is a serious medical condition and could result in blindness if not treated appropriately and quickly.

     Although PMR responds very well to corticosteroids, there is still concern for the adverse effects that occur with long-term steroid use.  This includes diabetes, osteoporosis, hypertension, worsening of cataracts, muscle weakness, and infection.  Patients taking corticosteroids must have their blood sugar, blood pressure, and body weight routinely checked. Due to the increased risk for osteoporosis, vitamin D and calcium supplements should be initiated when the corticosteroids are initiated.

Physical Therapy Management (current best evidence)

     There is currently no evidence for the use of physical therapy in the treatment for PMR.  However, as physical therapists, it is still important to be aware that patients may be referred to you with a primary diagnosis of PMR, or as a co-morbidity.  It is extremely important to be aware of the risk for developing GCA because, as stated above, this is a medical emergency.  See the Co-Morbidities section above for the associated signs/symptoms of GCA.

     If a patient with PMR begins to have increased complaints of muscle pain and stiffness, it is important to ask them if they are still taking their corticosteroids as prescribed. These medications must be tapered appropriately.  Patients may not be fully aware of that and may end their medications prematurely.

      Long-term corticosteroid use also leads to many side effects, such as weight gain, cataracts, mood swings, rounding of the face, difficulty sleeping, glaucoma, diabetes, easy bruising, and hypertension.  Osteoporosis and compression fractures can also be of great concern with these patients.

     Patients may also come into the clinic with a missed diagnosis of PMR.  It is important to keep the signs/symptoms and diagnostic criteria of PMR in mind so that patients get the appropriate treatment they need.

Alternative/Holistic Management (current best evidence)

     Some advocate the use of many different herbal and/or nutritional supplements as treatment for PMR although there is no evidence to support the use of such things.  Many of those supplements are intended to decrease the inflammatory response associated with PMR, improve muscle function and flexibility, and improve circulation.  Those supplements include:

• Evening primrose herb- provides essential fatty acids to produce prostaglandins
• Vitamin E- enhances the circulation system and promotes muscular strength and flexibility
• Vitamin C- anti-inflammatory
• Bioflavonoids- anti-inflammatory
• Bee pollen- improve energy and stamina
• Devil's claw- anti-inflammatory
• Comfrey herb- analgesic
• Passion flower, hops, and valerian herbs- muscle relaxants
• St. John's wort- anti-depressant
• Borage leaves- analgesic

     A copper bracelet may also be worn by some individuals to try to ward off rheumatic pain.

Differential Diagnosis

According to Nothnagl and Leeb, some important differential diagnoses of PMR to keep in mind include:

• Late-onset rheumatoid arthritis (LORA)
• Hypothyroidism
• Fibromyalgia
• Tumor
• Polymyositis/dermatomyositis
• Bursitis/Tendonitis
• Systemic small-vessel vasculitis
• Remitting seronegative symmetric synovitis with pitting edema

Case Reports/ Case Studies

• Polymyalgia rheumatic and exercise: a single case report on one woman [view article in EBSCOhost]
• Isolated lower extremity vasculitis in a patient with polymyalgia rheumatica [view article in EBSCOhost]

Resources

• American College of Rheumatology- http://www.rheumatology.org/practice/clinical/patients/diseases_and_conditions/polymyalgiarheumatica.asp
• National Library of Medicine - http://www.nlm.nih.gov/medlineplus/polymyalgiarheumatica.html
• National Institute of Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse - http://www.niams.nih.gov/Health_Info/Polymyalgia/default.asp
• Arthritis Foundation - http://www.arthritis.org/conditions/diseasecenter/pmr.asp

Recent Related Research (from Pubmed)

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References

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