Fibromyalgia is a chronic illness typically characterized by its cardinal symptoms: widespread pain; and fatigue. Some people who have fibromyalgia may complain only of pain. Most people, however, will experience a variety of symptoms and syndromes that fall outside the definition of fibromyalgia, yet frequently accompany it.
The symptoms most often associated with fibromyalgia include:
- Sleep disturbance
- Attention and memory difficulties
- Allergy-like sensitivity to drugs or medications
- Sensitivity to loud noises
- Intolerance to heat or cold
- Restless legs and/or cramps
Regional or organ-specific symptoms and syndromes, such as tension/migraine headache, temporomandibular joint disorder, irritable bowel syndrome, interstitial cystitis, and many other conditions are related to fibromyalgia and fall under the umbrella of Chronic Multisymptom Illnesses.
Fibromyalgia affects 2 to 4 percent of the U.S. population. It is more commonly diagnosed in females, but teens and males develop this condition as well.
Historically, there has been a lot of uncertainty about what constitutes fibromyalgia, what is going on in the body and even what to call this mysterious illness. In 1990, the American College of Rheumatology established research diagnostic criteria to give more structure to the definition of fibromyalgia.
The criteria include:
- Pain in all four quadrants of the body (both sides, above and below the waist, and around the axial skeleton [spine]) that lasts for 3 or more months
- Pain in at least 11 out of 18 possible tender points upon palpation with 4 kg of pressure (like during a tender point exam)
Originally these criteria were developed to ensure that researchers were studying a standardized population of people who met a specific set of criteria. They were not intended for diagnosing individual patients. Our research team is committed in particular to teaching health care providers that these criteria should not be rigidly adhered to when it comes to diagnosing individual patients. However, because these criteria have allowed a standardization of research in this area in recent years, a tremendous amount of excellent scientific study has occurred that has given fibromyalgia a measure of legitimacy in clinical settings.
Given that symptoms are highly subjective and wax and wane over time, doctors educated about fibromyalgia can confidently give a diagnosis that may encompass some elements of the ACR criteria as well as the more subtle nuances of symptom expression. Since there are no defining laboratory tests, doctors will make a diagnosis based on clinical features and symptoms. Patients often receive a diagnosis of fibromyalgia once all other illness options have been excluded.
While no one knows what actually causes fibromyalgia, infections, trauma, physical, emotional and even environmental stress can trigger the start of symptoms. People who have a rheumatic disease such as lupus or rheumatoid arthritis are at higher risk for developing fibromyalgia. Doctors and patients have long suspected that genetics play a role as well because fibromyalgia is often found in family members. In recent years, researchers, including our group, have begun to devote more attention and resources to the exploration of genetic links.
What we have learned
The ACR criteria were published roughly 16 years ago, and while still considered a “gold standard” for defining fibromyalgia, much research has been conducted since then to improve our understanding of this illness.What we have learned about tenderness: We now know that the number of tender points a person has is, in part, related to their pain threshold, and, in part, related to their level of distress. For this and other reasons, tender points are not a good measure of tenderness even though they are part of the formal diagnostic criteria. People can still have fibromyalgia if they don’t have 11 or more tender points.
What we have learned about pain processing: Through innovative technologies like functional MRI where we can see the brain’s response to pressure and heat stimuli, we and others have gathered a great deal of evidence suggesting that fibromyalgia is more a problem of pain processing at the level of the nervous system, spinal cord and brain than a problem in the periphery, e.g., muscle or tissue damage, or inflammation. So, now when your doctor says that fibromyalgia is “all in your head,” you may politely agree.
What we have learned about pain genetics: Certain genes are integral to regulating pain processing in humans, in particular a gene called COMT. Scientists have discovered recently that variants to this gene influence pain sensitivity and are specifically associated with increased pain sensitivity. Presence of these genetic variants and many others may impact how likely it is that someone will develop a chronic pain condition such as fibromyalgia or TMJD. In the long term, researchers are hoping these discoveries will help identify gene markers that can be used to diagnose and, ultimately, determine the most effective treatment for individuals with chronic pain.