Polymyalgia Rheumatica Diagnosis

You may have arrived at this website because your doctor has told you he or she thinks you have PMR. And after weeks and weeks of tests and waiting, you still don’t have a certain Polymyalgia Rheumatica diagnosis, or a diagnosis for anything else! You have been tested for just about everything under the sun, but PMR is a slippery customer and gives doctors and lab technicians the runaround. What is going on?
Well, it isn’t that your doctor isn’t doing his or her job properly. It really is the case that PMR is notoriously difficult to diagnose. There isn’t a definitive test, such as a blood test or a urine test that points with arrow-like sharpness at a diagnosis of PMR. So it’s not like rheumatoid arthritis, for example, where there is a substance in the blood called the RA factor that is a sure sign of the presence of the illness. All we have (or have had until recently) is a rough measure of inflammation in the body, revealed in the CRP test and the ESR tests.
CRP & ESR Tests
Th CRP test examines the level of a substance called C-Reactive Protein present in a blood sample. C-Reactive Protein is released into the blood stream by the liver as a response to inflammation.. The ESR test measures the Erythrocyte Sedimentation Rate in the blood. The test actually examines the rate of fall of red blood cells in a sample in a tall thin tube, and this again provides a measure of inflammation.
As useful as these tests are, they only confirm inflammation, and inflammation is present in a whole lot of other illnesses too. So inflammation on its own is not sufficient to point to PMR. The doctor has to take the measure of inflammation and link it with other symptoms.
Other Symptoms
The main cardinal symptom of PMR is severe pain and stiffness in both shoulders, and sometimes the hips. This is known as bilateral pain and stiffness. So if only one shoulder is affected, the evidence is pointing away from PMR. Also if the hips are affected but not the shoulders, there is likely to be another cause. It is also common for there to be stiffness in other areas of the body, often described as 'morning stiffness'. However this doesn't reflect the severity of the stiffness, which can be pretty disabling and also last all day.
Other potential symptoms include a general feeling of being unwell, a slight yet persistent fever, and a feeling of fatigue. About one in five PMR patients also have symptoms of the related condition Giant Cell Arteritis. These include severe headache, pain in the jaw, tenderness around the temple area, tenderness of the scalp, and visual disturbance. GCA is a very serious condition that has the potential to cause permanent loss of sight, so if you are suffering three or more of these symptoms you should seek immediate medical attention.
Further Diagnosis
To reach a confident diagnosis of Polymyalgia Rheumatica, doctors have to rule out a long list of other possible conditions that could be causing the symptoms. These can range from late onset rheumatoid arthritis (LORA), through osteoarthritis, to certain cancers. Knowing what some of the alternative diagnoses might be could actually feel slightly relieved that you turn out to have PMR, which in and of itself is serious but not life-threatening. Also, if you are reasonably fit and strong before you get PMR, you have every chance of making a full recovery with time. The same can’t be said of Rheumatoid Arthritis, which at the moment is a chronic illness that is with sufferers for life. So ruling out all the nasty alternatives is what takes the time.
The reason it is so important to go through all this process is because almost any symptoms will improve if you put a patient on steroids when they are feeling very unwell. But steroids may mask the symptoms of a more serious condition, which would simmer away untreated under cover of the steroid treatment. And in the case of PMR, patients are going to be on steroids for quite a long time. Steroid therapy causes all kinds of side effects that are cumulative, that build up over time. And so you can see that there is more than one reason for being careful about diagnosis. Having said that, one study in the UK in recent years found that as many as 50% of PMR cases diagnosed by GPs weren’t actually PMR at all. An alarming figure.
Developments in Polymyalgia Rheumatica Diagnosis
Things may be about to improve. In the last couple of years, more has been learned about the biochemistry of PMR – what is happening in your body when you become ill – and this new knowledge might be a key to faster and more accurate diagnosis. The key is a group of chemicals in the body called interleukins.
In a healthy person, the development of inflammation is a natural normal part of the immune system. Imagine you have a virus attacking your throat. In order to fight the virus, the bloodstream sends interleukins and other chemicals to your throat to do battle. They burn up a lot of energy and create havoc for a while – this causes the inflammation. But when the virus has been beaten, that inflammation should die down and the manufacture of interleukins should go back down to the normal level, helping the blood to maintain a healthy balance in the immune system. However, when we have an auto-immune illness, it is as though the body doesn’t know that the battle is over. The immune system continues to pour out interleukins like there is no tomorrow, setting up inflammation in what would otherwise be healthy tissue. The body is attacking itself.
There are quite a few interleukins, and they all have numbers to identify them. The big culprit in PMR (and GCA) is number 6, generally known as IL-6. Researchers have discovered that, in people with Polymyalgia Rheumatica, levels of IL-6 are elevated way above normal levels, and this is something very distinctive and specific to PMR. So it might be that we are on the verge of developing a more reliable and valid test for Polymyalgia Rheumatica diagnosis, something that would distinguish it from the alternative possible conditions. This would be a breakthrough, because it could dramatically reduce the number of misdiagnoses, and therefore prevent a lot of unnecessary steroid treatment. Unfortunately, at the moment, tests for IL-6 are only used in research studies, and it will be quite some time before they become widespread enough, and cheap enough, to be used routinely for diagnosis.
Another recent development is the use of PET scans. PET stands for Positron Emission Tomography, and is a method of developing three-dimensional images of the inside of the body. A PET scan can identify inflammation in specific areas, such as the large blood vessels. Researchers have discovered an interesting but rather alarming tendency for some people with complicated PMR (those who don’t get better within three years or so and/or have repeated relapses) to show signs of large vessel vasculitis (inflammatory disease of the blood vessels), particularly in the subclavian arteries. These are the big arteries that take blood towards the arms and shoulders. About 25% of PMR patients scanned in one study showed these signs. So it is also possible that use of imaging techniques like PET scans and CT scans could be used more widely to get better diagnosis.
We need to be realistic though. Polymyalgia Rheumatica is a very nasty illness that affects our lives dramatically, but on the whole it isn’t life-threatening. PMR isn’t going to be a medical priority any time soon. So for the time being we have to be patient and put up with the waiting for the blood tests.
What is important though, while you are waiting for your diagnosis and waiting to start your treatment that you learn about the symptoms of Giant Cell Arteritis and watch out for them. PMR if left untreated can lead to GCA, so if you develop an unusual headache and any vision disturbance, let your doctor know immediately. You can find out more about Giant Cell Arteritis here.