We hear all the time that it’s hard to diagnose fibromyalgia because it’s similar to so many other conditions. One of those similar conditions is polymyalgia rheumatica (PMR).
It’s possible that PMR could be misdiagnosed as fibromyalgia (or vice versa), or that either condition could be overlooked in someone who’s already diagnosed with the other.
These two conditions, however, are very different and require different treatments. Knowing the symptoms of both can help you recognize whether you may have a new or undiagnosed condition that needs to be addressed.
Polymyalgia and fibromyalgia are often confused because they both cause muscle pain throughout the body, and they have similar names.
However, they are different disorders with different causes. In fact, it is possible for a person to have both polymyalgia and fibromyalgia.
Polymyalgia rheumatica is an inflammatory form of arthritis. Fibromyalgia does not show traditional signs of inflammation, though some recent research from 2017 suggests it may also involve inflammation.
The causes of the two conditions are different:
- Polymyalgia is considered to be an autoimmune disease. Autoimmune disorders cause the body to attack healthy tissue by mistake.
- Fibromyalgia pain is thought to be caused by overactive nerves that make the body perceive pain despite there being no physical injury.
This means that fibromyalgia may occur because of the way that the brain and nerves perceive sensation, while polymyalgia develops due to a problem with the immune system.
There are some key differences between fibromyalgia and polymyalgia:
- Polymyalgia causes resting muscle pain whereas fibromyalgia is deep pressure pain.
- Polymyalgia commonly affects the elderly, while fibromyalgia is more common in those of middle age.
- Both conditions are associated with psychiatric conditions, in fibromyalgia there are abnormally higher mental functions.
- Polymyalgia responds to steroids, while fibromyalgia requires more targeted treatment.
- Polymyalgia involves inflammation, while fibromyalgia does not.
- Polymyalgia is believed to be an autoimmune disease, unlike fibromyalgia.
- Polymyalgia pain is located in specific areas whereas fibromyalgia is widespread.
- Polymyalgia typically appears quickly, unlike fibromyalgia.
Fibromyalgia is a diagnosis of exclusion. This means that when a person has widespread chronic pain throughout the body, and a doctor cannot find any other cause, they might diagnose fibromyalgia.
No single test can determine if a person has fibromyalgia. However, a physical exam that looks for specific tender points may be helpful. A doctor may also take blood samples to rule out inflammatory conditions, such as rheumatoid arthritis and polymyalgia.
Blood tests can usually diagnose polymyalgia. Most people with polymyalgia have elevated levels of inflammatory proteins in their blood. Their red blood cells may also show changes that are characteristic of inflammation.
A doctor may also perform other tests to rule out other inflammatory diseases, such as a biopsy or blood test for rheumatoid factor. These tests are standard for people with polymyalgia, but not for people with some other conditions.