Polymyalgia rheumatica (PMR)
What is polymyalgia rheumatica?
Polymyalgia rheumatica (PMR) is an inflammatory condition which presents muscle pains for the patient, mainly in the shoulders and thighs but also can occur in the buttock area. It is a relatively insidious onset condition, which develops over the course of several weeks during which the pain increases.
What are the main symptoms?
As the condition causes pain in the shoulders and thighs, the patient will encounter issues with their mobility, such as turning over in bed or getting in and out of a bath, due to the discomfort. Patients will experience severe stiffness in the morning that lasts longer than 45 minutes. Sometimes the stiffness can be so severe that basic tasks, such as dressing and walking, are difficult to carry out, and the condition can even interfere with a person’s ability to sleep. This can lead to severe tiredness and possibly depression. Patients can also have systemic symptoms, such as a fever or sudden loss of weight.
When diagnosing the condition, the doctor may first wish to conduct a diagnosis of exclusion, as the symptoms of PMR can be similar to other conditions. For patients, for example, who do not respond to treatment, the doctor will consider other causes.
What are the causes?
The causes of polymyalgia rheumatica are unknown. It is thought to be an autoimmune condition, which means it develops when the immune system, which defends the body against disease, attacks healthy cells in the body. It is also thought to be related to inflammation in the shoulder girdle, the structures around the shoulders. Some doctors believe the condition represents a type of "vasculitis," or inflammation in the blood vessels, and some imaging techniques have suggested that there is inflammation in the blood vessels in certain types of polymyalgia rheumatica.
The condition is also considered part of a spectrum of illness with polymyalgia rheumatica at the milder end of the spectrum and a condition called "giant cell arteritis" at the more severe end. In giant cell arteritis or temporal arteritis, the patient experiences inflammation of the blood vessels not just in the arms and the legs, but also in the blood vessels carrying blood to the brain and the back of the eye, so it characteristically presents with headache, and unfortunately patients can lose their sight because of the involvement of the blood vessels which supply the eye.
Who gets PMR?
PMR can develop from the age of 50 but is usually found in people over the age of 60. The average age at onset of the disease is 73. Women are about two times more likely to develop the disorder. The condition is also more common among Caucasian people in northern European countries.
What treatments are available?
The main treatment at present is prednisolone, which is a steroid treatment. There are also other steroid-sparing agent drugs, which are given if it is not possible to reduce the dose of steroids. There is some new research looking into prescribing patients with biologic therapy, including a drug called tocilizumab and an IL-6 receptor antagonist. At present research is still being conducted to test for their effectiveness, but the clinical trials are looking very promising. Physiotherapy can also be helpful in reducing pain and maintaining mobility.
What are the benefits of treatment?
The benefits of treatment are the same for any rheumatological disease, namely to improve life expectancy and enhance quality of life. As PMR is relatively mild compared to other similar conditions, it is effectively curable when treated, so patients will be able to feel better and return to their pre-PMR state when they have medication. If there is a relapse, treatment is highly effective at stopping the condition from persisting.
Are there any side effects of the treatment?
Prednisolone is a steroid drug, and like all steroids, there are notable side effects associated with them. Around 5% of patients will experience changes in their mental state when they take the medication. They may feel depressed and suicidal, anxious or confused. Other side effects of prednisolone include increased appetite, which can lead to weight gain, increased blood pressure, changes in the mood, such as spontaneous aggression, weakening of the bones, stomach ulcers, and increased risk of infection.
The key is to ensure the patient is not on the drug for very long, and the doctor will decrease the dosage over time. Furthermore, newer treatments and steroid-paring agents are now available which can be used to cut down on the side effects of the steroids and allow the patient to use them for a shorter period of time.
What self-help measures are there for patients?
Patients should ensure they have a healthy lifestyle with a balanced diet, some level of exercise and regular movement of the joints. Patients should keep their weight in check and avoid becoming overweight as this can put further pressure on the muscles and joints. Patients must also quit smoking, which can not only reduce the effectiveness of treatment but it can also increase the risk of developing other diseases and health complications.
However, patients will need to strike the right balance between activity and rest. Over-exercise will make the symptoms worse, but lack of enough activity will not help relieve morning stiffness. Weight-bearing exercises, such as walking or jogging, are particularly helpful for people with PMR.
When it comes to diet and nutrition, patients should be aware that steroid treatments usually reduce the amount of calcium absorbed from the gut and increase calcium loss through the kidneys. Therefore, patients should ensure they have at least 1000 mg of calcium a day, 1500 mg if they are over 60. Furthermore, patients should get at least 10-20 mg of vitamin D a day, through exposure to sunlight, eating foods such as oily fish, or supplements.
What is the outlook like for patients with PMR?
Patients normally have an excellent outlook, as the condition usually goes away quickly after a short time on medication and the patient will feel much better. Unfortunately, the symptoms of PMR can relapse, sometimes three or four years after a patient has recovered from the condition. But it usually does not relapse as bad as it was the first time the patient had the condition. It is relatively easy to put the patient back on treatment and unlikely there will be any need for returning to the use of steroid drugs.
Have there been any recent research discoveries or developments in the understanding and treatment of PMR?
Much research has been focused on biologic therapies as an alternative form of treatment to steroids, including tocilizumab and the IL-6 blocker. Greater understanding of the condition and the actual mechanisms at the cellular level are allowing developments in these treatments, and it is expected within the next five years they will become routine treatments prescribed to patients with PMR.
Another recent development is the use of ultrasound to detect giant cell arteritis. At the moment, a temporal artery biopsy takes place, where the doctor takes out a small piece of the artery on the side of the forehead and examines it under a microscope for signs of inflammation. Now there is a way in which this can be done through an ultrasound scan, so it is non-invasive and the patient does not require a biopsy.