What Is Polymyalgia Rheumatica?

Introduction

Polymyalgia rheumatica (PMR) is a relatively common rheumatic inflammatory condition that causes bilateral muscle pain and stiffness, especially in the shoulders, neck, arms and hips. The symptoms of polymyalgia rheumatica start quickly and are worse in the morning. It mostly affects people older than 65 years old and rarely people younger than 50 years old. The prevalence of PMR in the United Kingdom was higher in older people assigned female at birth (AFAB), it was also higher in people living in the south in comparison to people living in the north of the country.¹

Symptoms of polymyalgia rheumatica

The signs and symptoms of PMR involve both sides of the body and include the following:²

• Aches in upper arms, neck, shoulders, knees, thighs and hips
• The stiffness of the affected areas is worse in the morning and after long periods of inactivity
• Limited range of motions and functionality

There are also some general signs and symptoms including:

• Low-grade fever
• General tiredness and fatigue (malaise)
• Poor appetite
• Weight loss
• Depression

Causes of polymyalgia rheumatica

The exact cause of PMR is still unknown but two factors appear to be contributing to this condition:³

• Genetic: Certain gene variations may increase your chances of developing PMR.
• Environmental: Environmental triggers have been suggested for new cases of polymyalgia rheumatica, such as viruses, but no certain virus has been scientifically proven to cause PMR.

Risk factors of polymyalgia rheumatica

Several risk factors are associated with PMR, the most common factors are the following:⁴

• Advanced age: PMR is known to affect people of old age, people under the age of 50 rarely develop this condition, since most patients of PMR are 70 years and older.
• Sex: people assigned female at birth (AFAB) are 2 to 3 times more likely to be affected than people assigned male at birth.
• Ancestry: Polymyalgia rheumatica can affect all ethnic groups, but Caucasian people of Northern European (Norway, Sweden, Denmark, Finland, Iceland, United Kingdom, Ireland, Lithuania, Latvia and Estonia) descent appear to be at higher risk of developing PMR.

Diagnosis of polymyalgia rheumatica

Unfortunately, there is no specific test for PMR, multiple tests are usually carried out to look for inflammatory markers and to exclude other conditions.⁵

Two blood tests can check the level of inflammation: C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) CRP and ESR are carried out together, if both tests are normal the diagnosis is unlikely PMR. Sometimes ESR can be normal and CRP can be elevated, which indicates a positive diagnosis of PMR.

Inflammation is a marker for many conditions and that’s why it is important to carry out other tests to exclude other conditions like:

• Rheumatoid factor and anti-CCP antibodies to rule out rheumatoid arthritis.
• Thyroid function tests can be carried out to exclude hypothyroid and hyperthyroid glands, both conditions can cause muscle pain.
• X-rays and ultrasound scans to look for joints and bone conditions.
• Blood tests can be done to assess the function of the kidney and liver.

Treatment of polymyalgia rheumatica

PMR is a chronic self-limited condition, medications are introduced to relieve the pain and to improve or eliminate the muscle stiffness. 

Corticosteroids

Corticosteroids are the treatment of choice because they often result in the complete resolution of symptoms of PMR.The initial recommended dose by the European Alliance of Associations for Rheumatology (EULAR) and the American College of Rheumatology (ACR) is 12.5 to 25 mg/day of prednisolone. Slow tapering of the dose (reducing dosage of medication to reduce or discontinue it) after the symptoms are controlled was associated with fewer relapses and better control of the disease activity. Tapering is best guided by a decrease in pain and stiffness, better physical and mental functions, and normal inflammatory markers (ESR and CRP).⁶

The adverse effects of chronic use of corticosteroids are serious even with small doses and should be monitored and managed carefully. They include skin changes and thinning, weight gain, ocular (vision) changes, cardiovascular and gastrointestinal disorders, osteoporosis (bone weakness), mood changes and renal effects (hypertension).

Long-term use of corticosteroids can cause vitamin D deficiency by increasing the level of an enzyme that inactivates the vitamin, it is recommended to increase the dietary intake of food that contains vitamin D and calcium, patients who are incapable of this are advised to take vitamin D supplementation. Bisphosphonate therapy should be started for older patients and patients with previous bone fractures as a preventative measure against bone fractures.⁷

Other pharmacological therapy options 

NSAIDs have been used to control the pain, but they should be used carefully.

Corticosteroid-sparing agents (methotrexate) are sometimes used to reduce the adverse effects of steroids, but the results were inconsistent.

Physical therapy and exercises have been shown to improve the signs and symptoms of polymyalgia rheumatica, but both should be done under professional supervision.  

Conditions associated with polymyalgia rheumatica

Giant cell arteritis (GCA)

Up to 1 in 5 people with PMR can develop a more serious condition known as giant cell arteritis or temporal arteritis, where the lining of the arteries becomes inflamed, more commonly the arteries of the temporal region of the head or the temple.

Symptoms of GCA include sudden headaches and/or tenderness of the scalp, pain in the jaw especially during eating and wide opening of the mouth, and vision problems like double vision or loss of vision in one or both eyes.⁸

Giant cell arteritis is a serious condition that can result in permanent blindness or stroke if medical intervention isn’t in time. If you have any of these symptoms, contact a GP immediately, go to 111.nhs.uk or call NHS 111.

Summary

Polymyalgia rheumatica (PMR) is an inflammatory condition that commonly affects people older than 70 years and rarely affects people under 50 years of age. It is characterised by aches and stiffness of the neck, shoulders and hips. PMR is more common in people assigned female at birth (AFAB) and Caucasian people of Northern European ethnicity.

Diagnosis is based mainly on clinical evaluations and diagnostics to exclude other conditions that have similar manifestations as PMR. Treatment in most cases involves corticosteroids, and because of that monitoring and follow-up are essential to look out for side effects of corticosteroids. Physical therapy and lifestyle adjustments can contribute to the management plan and improve the quality of life of patients with PMR.

Polymyalgia rheumatica is challenging to diagnose due to the absence of specific diagnostic tests and the similarity of its clinical manifestations with other conditions. Current research seeks to enhance diagnosis and provide alternative treatment options for PMR. Raising awareness and patient education is essential in aiding individuals to manage their condition and live a healthy functioning life.