Polymyalgia Rheumatica

By Linda Rath | Sept. 13, 2024 

Polymyalgia rheumatica (PMR) is a form of inflammatory arthritis that mainly affects the shoulders, arms, hips and low back. Symptoms like pain and stiffness often appear suddenly – sometimes literally overnight – but can also develop over a few days or weeks. They usually occur on both sides of the body, are worse in the morning or after resting and get better with movement. For some people, morning pain and stiffness can make it hard to get out of bed or dress. About one-third of patients also develop systemic symptoms like fever, fatigue and unintended weight loss. Unlike other types of arthritis, PMR doesn’t cause swollen joints, making it difficult to diagnose.

Who is at risk?

These factors raise the risk of developing PMR:

• Age. PMR rarely affects anyone under 50, although it’s not entirely clear why. The average age at diagnosis is 70. 
• Sex. As with many rheumatic diseases, people assigned female at birth are more than twice as likely to develop PMR than people assigned male. That may be due in part to shifting hormone levels, but that’s probably not the whole explanation.
• Race. PMR is most common in white people living in Scandinavian countries and those of northern European descent.  It’s rare in other races and ethnicities. 
• Giant cell arteritis (GCA). An estimated 10% or more of people with PMR also develop a potentially serious condition called giant cell arteritis, which is inflammation of the blood vessels in the head, especially the temples. It can cause persistent, severe headaches and jaw pain. Untreated GCA can lead to vision loss or stroke. About half of people with giant cell arteritis also have PMR. The two conditions have a lot in common, including the same risk factors, genetic variations and treatment.

What causes PMR?

Experts believe that many rheumatic diseases are triggered by something in the environment, such as a viral infection, in people who have certain genes that make them vulnerable. For example, the HLA-DR4 family of genes is associated with joint inflammation in rheumatoid arthritis (RA), and may be involved in some cases of PMR, but it seems to vary with different groups of people. The genetic link is stronger in those who have both PMR and giant cell arteritis.

Some factors believed to trigger PMR include a reaction to the seasonal flu vaccine and possibly to the COVID-19 vaccine, although the link with COVID vaccination is controversial. A few people have developed PMR after particular cancer treatments.

A stronger association seems to exist between PMR and diverticulitis – inflammation in pouches that form in the large intestine, so it might have something to do with an imbalance in the microbiome, which is also linked to many other rheumatic diseases.

How is PMR diagnosed? 

Guidelines to diagnose PMR generally include the following factors:

• Sudden onset of morning stiffness lasting more than 45 minutes 
• Inflammation in one or both shoulders and hips, but not other joints. (This sets it apart from rheumatoid arthritis, which tends to develop in small joints in the hands, wrists and feet.)
• Age 50 and older
• Blood tests that don’t show rheumatoid factor (RF) or anti-citrullinated protein autoantibodies (ACPA). (These are common in rheumatoid arthritis.)
• Blood tests that show inflammation is high – either C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) – although these can also occur in healthy people.

PMR is challenging to diagnose because many other conditions have similar symptoms. Doctors often use ultrasound imaging to help pin down a diagnosis. Another way to confirm that it’s PMR instead of, say, osteoarthritis (OA) is to start a course of the corticosteroid drug, prednisone. PMR almost always gets better with prednisone within just a few days. Prednisone can have serious side effects, though, so this should only be tried when the diagnosis is pretty clearly PMR and after you have a thorough discussion about the pros and cons of prednisone with your doctor.

How is it treated?

The standard treatment for PMR has been an extended course of a corticosteroid, such as prednisone, because it quickly reduces pain and inflammation. The problem is that fully treating PMR can require taking steroids for two years or longer. Even then, symptoms may come back.

In 2015, guidelines for managing PMR came out that recommended highly individualized schedules for dosing and tapering. 

Weaning patients off of steroids like prednisone is crucial, because the longer patients stay on them, the more likely side effects are to occur. Steroid use can lead to an increased risk of infections, thinning bones and fractures, mood swings, memory problems, diabetes, high blood pressure, glaucoma, heart attack and stroke. 

The weaning process should be slow and careful. Getting off it too quickly can lead to withdrawal symptoms and a resurgence of symptoms. The goal is to reduce the original dose to about 10 mgs in the first month or two, then drop it another 1 mg each month and keep it as low as possible until the patient achieves full remission, usually in one or two years.

Because of the serious health risks of corticosteroids and because at least one-third of PMR patients taking it will relapse, researchers are constantly seeking better therapies. The first of these, a biologic medication called sarilumab (Kevzara), was approved by the FDA in 2023 for people with PMR who don’t get enough relief from steroids. Sarilumab is called an interleukin-6 (IL-6) blocker because of how it works in the immune system. Another IL-6 blocker, tocilizumab (Actemra) is approved for giant cell arteritis.

What should I keep in mind?

Many people with PMR can stop medication after a year or two and remain symptom-free, but others may need life-long treatment to prevent relapses. To minimize risks associated with treatment:

• Be sure you fully understand the risks and benefits of corticosteroids. Mild PMR sometimes goes away on its own, so discuss this possibility with your health care provider.
• While taking a corticosteroid drug, you should be closely monitored for side effects. Be aware of changes and report them immediately to your doctor. 
• Ask your doctor about taking calcium and vitamin D supplements while you’re on steroids to help prevent bone loss and reduce the risk of fractures. Some people lose 10% to 20% of their bone mass in the first six months of corticosteroid therapy.
• Get plenty of regular exercise to preserve strength and flexibility and counter some of the side effects of treatment.
• Emphasize a healthy, anti-inflammatory diet and restorative sleep.
• Corticosteroids can affect your memory and mood; know how to counter these problems with deep breathing, meditation or other healthy stress relievers that work for you.