Polymyalgia rheumatica (PMR) is a relatively common cause of widespread aching and stiffness in older adults. It can be difficult to diagnose because it rarely causes swollen joints or other abnormalities on physical exam. It may occur with another condition, giant cell arteritis.
What is polymyalgia rheumatica?
The typical symptoms of polymyalgia rheumatica (PMR) are aching and stiffness around the upper arms, neck, lower back and thighs. Symptoms tend to develop quickly, over a period of several days or weeks, and occasionally even overnight. Both sides of the body are affected. Involvement of the upper arms, with difficulty raising them above the shoulders, is especially common.
Aching and stiffness are worse in the morning, and tend to improve gradually as the day goes by, but periods of inactivity, such as a long car ride or sitting too long in one position, will cause stiffness to return.
Stiffness may be so severe that there is pain at night, difficulty getting dressed in the morning (for example, putting on a jacket or bending over to pull on socks and shoes), or difficulty getting up from a low chair. Occasionally, aching occurs in distal joints such as those of the hands and wrists.
What causes polymyalgia
The cause of PMR is unknown. The tendency for symptoms to begin abruptly suggests the possibility of an infection but, so far, no specific infection has been found. “Myalgia” comes from the Greek word for “muscle pain”, but tests for muscle damage, such as enzymes (a type of blood test) to actual biopsy, are all normal.
Recent evidence now suggests that PMR is an arthritis with a particular tendency to involve the shoulder and hip joints, and the bursae (or sacs) around these joints. Thus, the pain in the upper arms and thighs comes from the nearby shoulder and hip joints. PMR should not be confused with a condition called fibromyalgia, a condition that affects mainly younger adults and is not a form of arthritis.
Who gets polymyalgia
PMR occurs only in older adults and rarely in people younger than 50. The average age of onset of symptoms is 70, and many people who have PMR are in their 80s or even older. Women are affected somewhat more often than men, and the disease is more frequent in whites than nonwhites, but all races are susceptible. PMR is not unusual – in fact, it is diagnosed for the first time in older adults more frequently than rheumatoid arthritis.
How is polymyalgia
In PMR, results of blood tests to detect inflammation are usually abnormally increased. One such test is the erythrocyte sedimentation rate, or ESR. Another is the C reactive protein, or CRP. Both of these tests are typically significantly elevated in PMR but, in a small proportion of patients, these tests may be normal or only slightly increased.
How is polymyalgia
If the diagnosis of PMR is strongly suspected, a trial of low dose corticosteroids is given, usually in the form of 10-15 mg of prednisolone per day. If PMR is present, these medications will control the pain quickly. The response to corticosteroids can be dramatic – sometimes patients are better after only one dose – but improvement can be slower. However, if symptoms have not been completely relieved after 2 to 3 weeks of treatment, the diagnosis of PMR must be called into question and other diagnoses considered.
When symptoms have been controlled, the dose of corticosteroid medication is decreased gradually. The goal is to find the lowest dose that keeps the individual comfortable. Some people can stop corticosteroids within a year, but most will need a small amount of this medication for 2 to 3 years, sometimes longer, to keep aching and stiffness under control. Because the symptoms of PMR are so sensitive to even small changes in corticosteroid dose, it is not unusual for some of the symptoms to return as this medication is decreased. Consequently, both the blood tests and the corticosteroid dose must be monitored closely.
Living with polymyalgia
Once stiffness has subsided, normal activities can be resumed, including exercise within limits. Physical activity is important to maintain bone and muscle strength, and a physical therapy evaluation is helpful to start an exercise routine. Corticosteroids can cause side-effects, including higher blood sugar, weight gain, sleeplessness, osteoporosis (bone loss), cataracts, thinning of the skin and bruising, and muscle weakness. Monitoring for these problems, including bone density testing, is an important part of regular follow-up visits with the rheumatologist. Medication is often needed to prevent osteoporosis in older patients.
Because PMR can be associated with a more serious condition, giant cell arteritis (GCA), a patient who has PMR should immediately contact a physician if there are symptoms of headache, changes in vision, or fever.
in the treatment of PMR
PMR may be difficult to diagnose. Rheumatologists are specialists in musculoskeletal disorders and therefore are more likely to make a proper diagnosis as well as expertly manage medications to minimize side effects.
Points to remember
PMR affects adults over the age of 50.
Symptoms usually respond promptly and completely to low doses of corticosteroids.
Aching and stiffness tend to come on quickly in PMR, and are especially common about the shoulders, upper arms, neck, buttocks and thighs
Symptoms are worst at night and on rising in the morning.
Symptoms respond briskly to low doses of corticosteroids, but may recur as the dose is lowered.
(The writer is a Consultant Rheumatologist)