I am often asked whether or not I believe the diagnosis of fibromyalgia really exists. It is a controversial medical diagnosis, although also very common. The FDA recognizes fibromyalgia and there are two drugs that have FDA indications to treat the disorder. Despite this, many doctors are not sure it exists.
According to the CDC:
“Fibromyalgia is a disorder of unknown etiology characterized by widespread pain, abnormal pain processing, sleep disturbance, fatigue and often psychological distress. People with fibromyalgia may also have other symptoms;
- Morning stiffness
- Tingling or numbness in hands and feet
- Headaches, including migraines
- Irritable bowel syndrome
- Sleep disturbances
- Cognitive problems with thinking and memory (sometimes called "fibro fog")
- Problems with thinking and memory (sometimes called "fibro fog")
- Painful menstrual periods and other pain syndromes
It is thought that fibromyalgia is a rheumatological condition, meaning that it is inflammatory and perhaps auto-immune. It is sometimes described as a low level “simmering” auto-immune disease involving the muscles and fascia (sheets of connective tissue supporting the muscles).
The American College of Rheumatology (ACR) 2010 criteria for diagnosis includes:
- Widespread Pain Index (WPI) >7 and a symptom severity scale (SS) >5 or WPI 3-6 and SS >9.
- Symptoms have been present at a similar level for at least 3 months.
- The patient does not have a disorder that would otherwise explain the pain.
But then immediately after stating there are no other disorders present to explain the pain, the CDC states: “Fibromyalgia often co-occurs (up to 25-65%) with other rheumatic conditions such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and ankylosing spondylitis (AS).” So – up to 65% of patients with fibromyalgia have other conditions that can potentially explain the pain.
Also, take a look again at the list of other symptoms that can occur with fibromyalgia – sleep disturbance, for example, and irritable bowel syndrome. (Yes, I noticed the duplicate entry on “fibro fog” - perhaps the person from the CDC writing this page is a little forgetful.)
Curiously absent from the CDC discussion of fibromyalgia is reference to myofacial trigger points (MTP). At one time these were thought to be diagnostic of fibromyalgia, but the syndrome has expanded over the years, and the relationship to MTPs is optional at best. The existence of MTPs themselves has been questioned – perhaps this is just another non-specific manifestation of chronic pain, combined with a little confirmation bias.
Whether or not you think fibromyalgia is “real” depends on your definition of a medical diagnosis. Ideally a medical diagnosis is a discrete pathphysiological entity – there is something specific and definable going on, involving a specific part of the anatomy, a particular pathological process, or a physiological function outside of healthy parameters. The term “disease” is best reserved for these specific entities.
However, at times patients have clusters of symptoms that appear to occur often together. Our pattern recognition kicks in and we can recognize a recurring “syndrome,” however we may not understand the underlying cause (what we call “etiology”). This may be because the etiology of the syndrome is simply not currently understood, or it may be because the syndrome is not discrete or homogenous.
Even if a syndrome does not represent a single disease, it may still be real. The syndrome may be the final physiological effect of multiple possible causes – a final common pathway of symptom development.
Complicating our classification scheme of diagnoses, even discrete and uncontroversial diseases often have overlapping signs and symptoms with other diseases. Few symptoms are “pathognomonic,” meaning that they occur with only one disease and by themselves are diagnostic.
Many symptoms, diseases, and syndromes are what we call “co-morbid,” which means they exist together and reinforce each other. There is no simple line of cause and effect, but a complex web of interacting and self-reinforcing morbidity.
For example, sleep disturbance is listed as co-morbid with fibromyalgia, but does the sleep disturbance cause fibromyalgia or does fibromyalgia cause the sleep disturbance? Perhaps they cause each other. Perhaps cognitive symptoms and chronic pain are both caused by depression, which in turn is worsened by the pain and poor sleep.
Further, if you treat any entity in this web of symptoms, the other symptoms tend to get better. Improve sleep in fibromyalgia patients, and their other fibromyalgia symptoms improve.
So – is fibromyalgia “real?” So far no one has established a specific discrete pathophysiological etiology that is fibromyalgia. Further, many of the symptoms of fibromyalgia are nonspecific and are highly co-morbid with other disorders that might be causative. From that point of view fibromyalgia does not exist as a specific disease or etiology.
However, fibromyalgia can be a useful term to describe the complex web of comorbid symptoms described above – chronic pain, fatigue, sleep disturbance and cognitive symptoms. It needs to be recognized, however, that this is a very heterogeneous group and different patients may arrive at this symptom complex in different ways.
From a practical point of view, when treating patients with fibromyalgia (whatever you think that means), practitioners identify and treat each comorbid factor. Treat the pain, treat the sleep disturbance, and treat the depression. Factors that might be contributing to the symptom complex (obesity, vitamin deficiencies, arthritis, etc.) also need to be identified and treated. Often significant lifestyle changes may be necessary to really turn things around, such as engaging in regular exercise (which can be challenging in many patients).
The two medications indicated for fibromyalgia, Lyrica and Cymbalta, are both also indicated for the treatment of chronic neuropathic pain. Saying that they also treat the pain of fibromyalgia really doesn’t add anything specific – they are still just treating pain. They are not targeted at any specific underlying cause of fibromyalgia.
I think it is reasonable to treat fibromyalgia as a syndrome – a comorbid complex that is frequently encountered. My strong reservation, however, is that fibromyalgia not be treated as a specific disease. That has not been established. Perhaps it is a placeholder on our current ignorance, which will eventually be rectified. Perhaps it will forever be a syndrome without a specific pathology or single cause.
In the end the label itself is not that helpful (although patients often feel better being given such labels), other than as a convenient short hand. You are still left individually evaluating and treating the specific symptoms and comorbid factors in individual patients, no matter what you call them.
Steven Novella, M.D. is the JREF's Senior Fellow and Director of the JREF’s Science-Based Medicine project.