Fibromyalgia Pain Has Central Nervous System Origins

Fibromyalgia Pain Has Central Nervous System Origins

Although it continues to be widely misunderstood, Fibromyalgia Syndrome (FM) is nonetheless now the second most common rheumatic disorder, behind only osteoarthritis. FM is considered to be a lifelong central nervous system disorder — responsible for amplified pain that shoots through the body in persons who suffer from it. In addition to pain, individuals suffering with fibromyalgia often experience fatigue, poor quality of sleep, and difficulties with memory and concentration, among other symptoms.

ClauwDDaniel Clauw, M.D. , a professor of anesthesiology at the University of Michigan, analyzed the neurological basis for fibromyalgia in a plenary session address delivered last week at the American Pain Society’s 34th Annual Scientific Meeting, which was held May 13–16, 2015 at the Palm Springs Convention Center in Palm Springs, California.

The American Pain Society is a multidisciplinary community that brings together a diverse group of scientists, clinicians, and other professionals to increase the knowledge of pain and transform public policy and clinical practice to reduce pain-related suffering. The APS’s Annual Scientific Meeting (ASM) offers innovative, collaborative, and interdisciplinary pain science educational sessions focused on diagnosis, treatment, management, and research of acute pain, chronic cancer and non cancer pain, and recurrent pain.

“Fibromyalgia can be thought of both as a discreet disease and also as a final common pathway of pain centralization and chronification. Most people with this condition have lifelong histories of chronic pain throughout their bodies,” said Dr. Clauw. “The condition can be hard to diagnose if one isn’t familiar with classic symptoms because there isn’t a single cause and no outward signs.”

Fibromyalgia has no definitive diagnosis, so doctors are obliged to rely on a patient’s medical history and symptoms when diagnosing the illness, excluding other conditions that might cause similar amounts of widespread pain. One of the primary abnormalities in fibromyalgia is an imbalance between the levels of neurotransmitters in the brain that affect pain sensitivity. Fibromyalgia’s cause remains unknown, although it is thought to be probably a combination of genetics and environment.

In his address, Dr. Clauw explained that fibromyalgia pain originates more from the brain and spinal cord than from the body areas in which persons may experience peripheral pain, noting that the condition is believed to be associated with disturbances in how the brain processes pain and other sensory information. He advises physicians to suspect fibromyalgia in patients with multifocal (mostly musculoskeletal) pain that cannot be fully explained as being caused by injury or inflammation.

“Because pain pathways throughout the body are amplified in fibromyalgia patients, pain can occur anywhere, so chronic headaches, visceral pain and sensory hyper-responsiveness are common in people with this painful condition, Dr. Clauw continued. “This does not imply that peripheral nociceptive input does not contribute to pain experienced by fibromyalgia patients, but they do feel more pain than normally would be expected from the degree of peripheral input. Persons with fibromyalgia and other pain states characterized by sensitization will experience pain from what those without the condition would describe as touch.”

Dr. Clauw observed that because fibromyalgia pain originates in the central nervous system, treatment with opioids or other narcotic analgesics is usually not effective because these drug agents don’t reduce neurotransmitter activity in the brain. He said these drugs have never been shown effective in treating fibromyalgia patients, and there is even evidence that opioids might actually worsen fibromyalgia and other centralized pain states. He advises clinicians to integrate pharmacological treatments, such as gabapentinoids, trycyclics and serotonin reuptake inhibitors, with nonpharmacological approaches like cognitive behavioral therapy, exercise and stress reduction.

A number of pharmacological treatments for fibromyalgia are available by prescription. The first to be approved by the U.S. Food and Drug Administration (FDA) to treat fibromyalgia was pregabalin (Lyrica); the second was duloxetine (Cymbalta); and the third milnacipran (Savella). According to the National Fibromyalgia Association (NFA) other FM medications are currently under development, and may soon receive FDA approval to treat fibromyalgia.

Additionally, healthcare providers may treat patients’ FM symptoms with non-narcotic pain relievers (e.g. tramadol) or low doses of antidepressants (e.g. tricyclic antidepressants, serotonin reuptake inhibitors) or benzodiazepines. Patients must remember that antidepressants are “serotonin builders” and can be prescribed at low levels to help improve sleep and relieve pain. If the patient is experiencing depression, higher levels of these or other medications may need to be prescribed. Lidocaine injections into the patient’s tender points also work well on localized areas of pain. An important aspect of pain management is a regular program of gentle exercise and stretching, which helps maintain muscle tone and reduces pain and stiffness.

“Sometimes the magnitude of treatment response for simple and inexpensive non-drug therapies exceeds that for pharmaceuticals,” Dr. Clauw advises. “The greatest benefit is improved function, which should be the main treatment goal for any chronic pain condition. The majority of patients with fibromyalgia can see improvement in their symptoms and lead normal lives with the right medications and extensive use of non-drug therapies.”

Dr. Clauw has become an internationally known expert in chronic pain, and especially the central nervous system contributions to chronic pain states, performing past or ongoing research on conditions such as low back pain, osteoarthritis, vulvodynia, endometriosis, irritable bowel syndrome, and temporomandibular joint disorder. He oversees a multidisciplinary group that performs both mechanistic studies and clinical trials in overlapping conditions characterized by chronic pain and fatigue, including fibromyalgia, chronic fatigue syndrome, and Gulf War Illnesses, and has been principal investigator of NIH and Department of Defense grants studying this spectrum of illness continuously since 1994. The University of Michigan Chronic Pain and Fatigue Research Center currently has several million dollars per year in federal funding to study these disorders.

Dr. Clauw and his group have been instrumental in establishing that the systemic conditions noted above, and regional pain syndromes such as interstitital cystitis, low back pain, and irritable bowel syndrome all have common pathogenic and clinical features. One of the primary areas of interest of his group has been in studying sensory processing in these conditions, and in demonstrating that many patients with these conditions have a widespread disturbance in pain processing. Current work is establishing the nature of the central pain processing abnormality in these conditions, using a variety of approaches, including functional MRI.

Dr. Clauw also directs the Center for the Advancement of Clinical Research (CACR) at the University of Michigan. The CACR provides infrastructure and support for clinical and translational research for the Medical School from protocol development through subject recruitment, performance, and monitoring of study conduct, to data management and analysis.

For more information on fibromyalgia, visit:
http://www.fmaware.org/

Based in Chicago, the American Pain Society (APS) is the professional home for investigators involved in all aspects of pain research including basic, translational, clinical and health services research to obtain the support and inspiration they need to flourish professionally. APS strongly advocates expansion of high quality pain research to help advance science to achieve effective and responsible pain relief. The APS 35th Annual Scientific Meeting will be held May 11 – 14, 2016, at the Austin Convention Center in Austin, Texas.

For more information on APS, visit:
http://www.americanpainsociety.org

Sources:
American Pain Society
University of Michigan Chronic Pain and Fatigue Research Center
National Fibromyalgia Association

Image Credit:
University of Michigan

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