People who suffer from chronic pain syndromes like fibromyalgia, irritable bowel syndrome, temporomandibular disease (jaw pain), or pelvic pain may have more in common than doctors once believed. Recent research has uncovered some new understanding about the way pain develops and is perceived by the affected individual that may link these conditions together. In this review article, pain scientists present the latest information about one condition in particular: fibromyalgia.
Coming up with a definition for fibromyalgia hasn’t been easy. Scientists want to describe it by what they know of the underlying pain mechanism. You might read that it is neurohormonal mediated chronic pain syndrome. That simply means it is believed that the nervous system and the endocrine (hormone) system are somehow both involved in creating the pain signals that don’t seem to get turned off or even turned down.
But if you ever talk to someone with fibromyalgia or you yourself are a fibromyalgia sufferer, then you know the best way to describe it is pain everywhere. The muscles are stiff, sore, and tender. The joints ache. There are headaches, difficulty sleeping, numbness and tingling, and problems with bowel and bladder function. In fact, up to 50 or more other distressing symptoms have been reported in association with fibromyalgia.
One thing scientists agree on about chronic pain of this type: it is centrally mediated. What does that mean? It means the problem isn’t coming from the muscles, joints, skin, or other soft tissues. It is originating within the systems and most likely the central nervous system (brain and spinal cord) with effects on all the peripheral tissues. Since most of these patients experience pain with input or stimuli that isn’t usually painful, it is suspected that there’s a problem with pain or sensory processing, rather than some disease, inflammation, or impairment of the area that actually hurts (e.g., the back, the hips, the wrists).
New information is now available on chronic pain mechanisms because of advances in technology (e.g., functional imaging), genetics, and experimental pain testing. Although there is a link between brain function and somatic (body) illnesses like fibromyalgia, this condition is no longer considered a psychiatric (mental) illness like it was in the past.
Functional brain imaging shows areas of the brain that light up when pressure is applied to painful areas of the body. All indications are that once the central pain mechanisms get turned on, they wind up until there’s pain even when the stimulus (e.g., pressure, heat, cold, electrical impulses) is no longer there. This phenomenon is called sensory augmentation. There is some evidence that people with fibromyalgia have a decrease in their reactivity threshold. In other words, with a low threshold, it only takes a small amount of stimuli before the pain switch gets turned on.
We still don’t know why this happens. Many theories are being tested. It looks like the area of the brain that is in charge of sensory integration (taking in, processing, and making sense of all sensory stimuli) is hyperactive. Instead of properly processing the messages, it amplifies (turns up the volume) on them. Several studies using Single-Photon-Emission Computed Tomography (SPECT) have shown changes in the blood flow to certain areas of the brain. In some places of the brain, there was increased blood flow, while in other areas, the tests showed decreased blood flow. These altered patterns of blood circulation could be part of the problem.
MRIs of the brain have confirmed that patients with fibromyalgia process pain in the same areas of the brain as individuals without fibromyalgia. The difference is again with the amount of stimuli needed to activate those pain mechanisms. People with fibromyalgia have a narrow range of pain tolerance. And because women are affected much more often than men, it is suspected that the endocrine (hormone) system must be involved somehow.
What about other factors that are suspected such as genetics or environmental stressors? Since fibromyalgia (and other chronic pain syndromes) tend to run in families, it’s natural to think there might be an inherited component. This hasn’t been proven yet but scientists are actively studying specific genes, receptors for pain and other neurotransmitters, and chemicals involved in stress responses. Fibromyalgia seems to be triggered (or started) as a result of stress or trauma. Many different environmental stressors have been identified as triggers including physical injury from a car accident (or other type of accident), infections such as Epstein-Barr virus or Lyme disease, thyroid disorders, and post-traumatic stress disorder (PTSD) linked with abuse, torture, or war.
By studying the biochemical pathways of patients with fibromyalgia, scientists have been able to identify ways to treat this problem with medications. They discovered that opioid-based (narcotics) don’t work but serotonin (a neurotransmitter that regulates mood, appetite, and muscle contraction) does. Along with pharmaceutical treatment for fibromyalgia, cognitive behavioral therapy (CBT) is advised. Working with a psychologist or counselor trained in pain management techniques helps the affected individual learn to minimize responses to pain and alter the perception that pain controls their life. In this way, they can stay as functional as possible until scientists fully unravel the pain mechanisms and find ways to control them.
Because there are so many variables and factors involved in chronic pain syndromes like fibromyalgia, treatment has evolved over time to become multidisciplinary. Besides medication and cognitive behavioral therapy, patients are also encouraged to stay active and exercise. Studies now show that exercise can be as helpful as medications for chronic pain conditions. Aerobic or cardiovascular training seems to be the most helpful. Low-impact activities like walking or biking, or even better, nonimpact exercise such as swimming are advised. Patients seem to do best when they progress slowly but gradually.
In summary, the authors show how our thinking about fibromyalgia and other chronic pain syndromes has shifted from seeing these conditions as coming from the affected areas and more toward an understanding of the central (systems-wide) mechanisms. This new understanding has changed treatment approaches more toward a multidisciplinary model. Evidence supports finding the right combination of medications along with modifying thoughts and actions. Recent breakthroughs in understanding of pain, brain function, and the details of chemical and biologic responses in patients with fibromyalgia suggest better treatments are on the horizon — perhaps even a cure for or prevention of this painful condition.