Polymyalgia rheumatica (PMR)/ Giant Cell Arteritis (GCA)

Definition

Polymyalgia rheumatica (PMR) is an inflammatory disorder that causes muscle pain and stiffness usually in elderly. The pain and stiffness occurs in shoulders, neck, upper arms and hips. Symptoms of PMR usually begin quickly, and intense pain may develop within two weeks. Most people who develop PMR are older than 65 years. This is relatively less common in India. It rarely affects in people below 50 years.

Anti-inflammatory drugs called corticosteroids improve the symptoms of PMR, but these drugs require careful monitoring for serious side effects.

PMR is related to another inflammatory disorder called giant cell arteritis (GCA), which can cause headaches, vision difficulties, jaw pain and other symptoms. It's possible to have both of these conditions together.

 

Symptoms

The signs and symptoms of PMR usually occur on both sides of the body and may include:

  • Aches or pain in and around shoulders (often the first symptom). 

  • Aches or pain in neck, upper arms, buttocks, hips or thighs. 

  • Stiffness in affected areas, particularly in the morning or after being inactive for a long time, such as a long car ride and usually pain intensity is very high. 

  • In contrast rheumatoid arthritis usually wrists and knees are not commonly involved  

  • Mild or low-grade fever with Fatigue 

  • Loss of appetite and weight loss 

Causes

The exact cause of PMR is unknown. However, there are two factors that appear to be involved in the development of this condition, including. Some genes may increase your susceptibility to developing PMR. New cases of PMR tend to come in cycles and may develop seasonally, which suggests that an environmental trigger, such as a virus, might play a role.

 

Giant cell arteritis 

PMR and another disease known as GCA share many similarities. GCA results in inflammation in the lining of arteries, most often the arteries located in the temples. GCA usually causes headaches, jaw pain, vision problems and scalp tenderness. In some patients GCA can lead to permanent vision loss.

PMR and GCA may actually be the same disease but with different manifestations. The overlap between the two diseases is significant. As many as 30 percent of people with PMR may also develop GCA and half of the people with GCA may also have PMR overlapping.

 

Complications

Symptoms of PMR are often so distressing and can greatly interfere with day to day activities. The pain and stiffness may contribute to difficulties with the following tasks. The major dreaded complication of the GCA/PMR is the acute vision loss. Hence an early diagnosis and treatment is recommended in this condition.

 

Tests and diagnosis                                                                                                                  

A general physical exam and the results of tests will help the doctor determine the cause of pain and stiffness. Blood tests: The complete blood counts (CBC) and for signs of inflammation, but your doctor also may recommend additional tests to rule out other conditions that have similar symptoms to PMR. Test results helpful in making a diagnosis of PMR include the following: Erythrocyte sedimentation rate (ESR):  An increased rate occurs and a very high rate is one of the because of certain changes to red blood cell properties in response to inflammation. C-reactive protein (CRP) test also indicates increased inflammation. Even the level of CRP is also elevated. There is no specific test available currently which can identify the PMR/GCA.

 

Imaging tests 
Magnetic resonance imaging (MRI) or ultrasound imaging to may help to find the inflammation of tissues within the shoulder and hip joints which may help to ascertain the diagnosis of PMR. These images may also help identify or rule out other causes of pain. Neither procedure exposes you to radiation.

When GCA is suspected a biopsy of the artery in one of your temples may be performed. This procedure is done under local anesthesia. A tiny sample of the artery is taken and then examined in a laboratory for signs of inflammation.

 

 

Treatments and drugs

Treatment is long and may be needed for a year or more.  But the symptoms of PMR will be better after the first course of treatment. And pain and stiffness will reduce within few days. Some it may relapse despite continued treatment and may need additional treatment.

Drugs used are

Corticosteroids; PMR is usually treated with a low dose of oral corticosteroid- prednisone. A daily dose to start with is usually 10 to 20 milligrams a day and may be gradually increased if required. Relief from pain and stiffness usually occur within the first two or three days. If symptoms are not better in a few days, it's likely it may not be PMR. In fact, response to medication is one way confirm the diagnosis.

After the first two to three weeks of treatment, steroids are gradually decreased depending on symptoms and the results of ESR and C-reactive protein. The goal is to keep on as lesser dose of steroid possible without triggering a relapse in symptoms. Most people with PMR need to continue the corticosteroid treatment for one to two years. Frequent follow-up visits to monitor how the treatment is working and whether or not you are having any side effects.

People who taper off the medication too quickly are more likely to have a relapse. Twenty percent or more of people with PMR will have a least one relapse when tapering off the corticosteroids. About 10 percent of people who successfully finish corticosteroid treatment will have a relapse within 10 years of the initial treatment.

 

Calcium and vitamin D supplements 
Calcium and vitamin D supplements are prescribed to help to prevent osteoporosis induced by corticosteroid treatment.

Other medications 
Methotrexate : This immune-modulator medication that may help lower the dose of corticosteroid. It's often given long term, for a year or more.

Anti-TNF drugs:  These drugs block TNF and reduce inflammation. Research results have been mixed on using these medications in PMR, but they might be helpful for people who can't take corticosteroids, such as people with diabetes or osteoporosis.

 

Physical therapy
It is recommend physical therapy to help you regain strength, coordination and your ability to perform everyday tasks after a long period of limited activity that PMR often causes. In addition eat a healthy diet, exercise regularly and where necessary use assistive devices.