Afflicting up to 5 percent of the U.S. population, mostly women, fibromyalgia is characterized by widespread pain and range of function problems. A new study in The Journal of Pain reports there is close association between obesity and disability in fibromyalgia patients.
The purpose of the study, conducted by University of Utah researchers, was to evaluate the relationship between fibromyalgia and obesity. They hypothesized that obesity significantly adds to the disease and disability burden of the condition. Two hundred fifteen fibromyalgia patients were evaluated in the study and given several physical tests to measure strength, flexibility, range of motion, and strength. Heart rates and sleep quality also were assessed.
The authors reported that consistent with previous studies, obesity is common among those with fibromyalgia. Half the study sample was obese and an additional thirty percent were overweight. Also consistent with previous findings, obese patients in this study showed increased pain sensitivity, which was more pronounced in lower body areas. The obese patients also had impaired flexibility in the lower body and reduced strength.
The study concluded that obesity is a common comorbidity of fibromyalgia that may compromise clinical outcomes. The adverse impact of obesity is evidenced by hyperalgesia, disability, impaired quality of life and sleep problems. The authors also noted that recent evidence suggests weight loss improves fibromyalgia symptoms, perhaps resulting from patients adopting healthier lifestyles and taking more positive attitudes toward symptom management, and overall quality of life.
A study in the Oct. 15 issue of the Journal of Clinical Sleep Medicine found that adults with fibromyalgia had a much higher prevalence and risk of restless legs syndrome than healthy controls. The study suggests that treating RLS may improve sleep and quality of life in people with fibromyalgia.
Results show that the prevalence of restless legs syndrome was about 10 times higher in the fibromyalgia group (33 percent) than among controls (3.1 percent). After statistical adjustments for potential confounders such as age, gender and ethnicity, participants with fibromyalgia were 11 times more likely than controls to have RLS (odds ratio = 11.2). As expected, considerable sleep disruption was reported by participants with fibromyalgia using the Pittsburgh Sleep Quality Index, Insomnia Severity Index and Epworth Sleepiness Scale. In the fibromyalgia group these sleep problems were more severe among people who also had RLS.
“Sleep disruption is common in fibromyalgia, and often difficult to treat,” said contributing author Dr. Nathaniel F. Watson, associate professor of neurology at the University of Washington in Seattle, Wash. “It is apparent from our study that a substantial portion of sleep disruption in fibromyalgia is due to restless legs syndrome.”
The research team led by Dr. Watson and lead author Dr. Mari Viola-Saltzman of Loyola University Medical Center in Maywood, Ill., studied 172 people with fibromyalgia who had a mean age of 50 years; 93 percent were female. They were compared with 63 healthy controls who had a mean age of 41 years.
Fibromyalgia was identified by self-report or review of the medical records, and it was confirmed on examination according to published guidelines regarding the presence of pain that is chronic and widespread pain . Pain was assessed by subjective report and by objective measurement with a dolorimeter, a spring-loaded gauge that is used to apply standardized rates of pressure to tender points on the arms and legs.
According to the National Institute of Arthritis and Musculoskeletal and Skin Diseases, fibromyalgia can cause significant pain and fatigue. It is estimated to affect 5 million Americans age 18 or older, and between 80 and 90 percent of those diagnosed with fibromyalgia are women. The causes of fibromyalgia remain unknown.
Restless legs syndrome was diagnosed using a self-administered, validated questionnaire. RLS is a sleep-related movement disorder that involves an urge to move the legs that is usually accompanied or caused by uncomfortable and unpleasant sensations in the legs. This urge begins or worsens during periods of rest or inactivity, is partially or totally resolved by movement, and worsens or only occurs at night. RLS occurs 1.5 to two times more commonly in women than in men.
Watson noted that treating restless legs syndrome may be one of the keys to reducing fatigue and improving quality of life in people with fibromyalgia. RLS often can be successfully treated with a medication such as pramipexole or ropinirole.
“Since restless legs syndrome is a treatable condition, diagnosing and treating RLS in fibromyalgia patients has the potential to improve their sleep,” Watson said.
According to the authors, the cross-sectional nature of the study did not allow for an examination of causality. However, several aspects of the two syndromes suggest a logical overlap. Both disorders involve sensory abnormalities, and a similar pathophysiology of the system that regulates the neurotransmitter dopamine has been proposed for both syndromes. Furthermore, restless legs syndrome may be induced by antidepressants, which are a common treatment for pain and depression in fibromyalgia. Also, exercise has been shown to improve the symptoms of both syndromes.
The study was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases of the National Institutes of Health and by the National Fibromyalgia Research Association.
Adolescents with fibromyalgia who are physically active report lower levels of pain and disability, according to findings of a multicenter study published in The Journal of Pain, published by the American Pain Society.
Led by researchers at Cincinnati Children’s Hospital, this study is the first to use actigraphy-based physical activity monitoring to measure the relationship of pain, perceived functional impairment and depressive symptoms in adolescents with juvenile primary fibromyalgia syndrome (JPFS). For the research, 104 adolescents ages 11-18 were fitted with hip-mounted actigraphs for one week. The battery-powered device measures the amount and intensity of human physical activity.
The research objectives were to measure physical activity levels in adolescents with JPFS, examine differences and characteristics of high and low activity subjects, and explore the impact of psychiatric disorders on physical activity. The objective activity measurements were intended to address concerns about the reliability of self reports on the impact of pain on physical activity, and validate observations that some JPFS patients remain vigorously active while enduring significant pain.
Results showed that adolescents with JPFS did not engage in physical activities and aerobic exercise at levels recommended by their physicians. Just 23 percent of the subjects participated in 30 minutes of daily moderate-to-vigorous physical exercise, and only one adolescent engaged in 60 minutes of exercise every day. Low levels of exercise in these patients are troubling to clinicians who view exercise as a major component for improved pain management.
Another key finding was that higher pain intensity ratings were not significantly associated with lower levels of activity in the group as a whole. The authors noted that adolescents with JPFS have other symptoms that may diminish interest in physical activity, such as fatigue and impaired sleep. The authors also noted that higher pain levels in the least active group may be related to their decreased activity or vice versa.
Further, the inactive group had higher levels of depressive symptoms and functional disability, according to parent reports. However, in the small number of JPFS patients who maintained very high levels of physical exercise, the reported pain levels were lower than the inactive group, perhaps due to exercising, and their parents reported they had lower depressive symptoms and disability than inactive subjects.
Is the science of diagnosing pain causing a number of pain sufferers to defend their honor? Research out of the University of Cincinnati is examining the diagnosis of pain that evades scientific testing, and the additional emotional suffering that can result for the patient.
The research by Elizabeth Sweeney, a doctoral candidate in UC’s Department of Sociology, was presented August 16 at the 105th annual meeting of the American Sociological Association in Atlanta. The paper, “Defining Reality: How Biomedical Researchers Determine the Existence of Pain,” analyzed more than 20 articles randomly selected from the peer-reviewed international academic journal PAIN®, the official publication of the International Association for the Study of Pain.
Sweeney examined the journal’s content to determine how pain is measured and defined in terms of type of pain, location of pain, its causes, severity, duration, response to treatment, methods of detection and symptoms. Because of these evidence-based diagnostic tests, the paper states that sufferers of chronic pain — conditions that frequently cannot be localized or pointed out on a scan or test — are often put in the position of defending the legitimacy or the reality of their condition.
Examples of these chronic pain sufferers of unexplained or “contested” illnesses can include patients with Chronic Fatigue Syndrome, Complex Regional Pain Syndrome (CRPS), fibromyalgia and Gulf War Syndrome.
“It is apparent from this research that the missing link in much of biomedical research is any viable attempt to understand the subjective experience of pain,” Sweeney writes.
“A diagnosis, simple though it may seem, constitutes not only the legitimacy of one’s illness, but also the validation of one’s sanity and honor — evidence that the patient is not psychologically unstable and is not ‘faking’ it,” says Sweeney.
The paper details that the journal, PAIN®, which for more than 30 years has focused on the study and research of pain, is considered one of the world’s premiere sources of biomedical research on pain. The articles that were analyzed were published between May 2008 and May 2009.
Demonstrating the challenges that pain and chronic pain pose to Western medicine, Sweeney concludes that deconstructing biomedical research on pain will better pave pathways of understanding in diagnosing and treating chronic pain sufferers.
Chronic muscular pain may be linked to a previously unknown principle for how pain signals are transmitted in the human body.
This is shown by Umeå University researchers Tuija Athanassiadis and Karl-Gunnar Westberg, in collaboration with Canadian associates, in the scientific journal PLoS ONE.
Muscles have sensory organs called muscle spindles. Their task is to inform the brain of changes in muscle length. Muscle spindles therefore contain a special type of large diameter nerve filaments that signal stretch of the muscle. The Umeå scientists’ studies show that muscle spindles also contain fine nerve filaments with pain receptors. When a muscle is damaged as a result of overloading, these pain receptors are activated by the release of a signal substance from the neighboring stretch-sensitive nerve filaments in the muscle spindle.
It was previously believed that the pain receptors in muscles were exclusively found in the membranes that surround the muscles or in connection with the blood vessels in the muscle. With these new findings the Umeå researchers are drawing attention to a hitherto unknown and interesting mechanism. Damage to the stretch-sensitive nerve filaments of the muscle spindle may contribute to and sustain chronic pain in jaw muscles as well as in other muscles.
A recent University of Iowa study reveals a biological link between pain and fatigue and may help explain why more women than men are diagnosed with chronic pain and fatigue conditions like fibromyalgia and chronic fatigue syndrome.
Working with mice, the researchers, led by Kathleen Sluka, Ph.D., professor in the Graduate Program in Physical Therapy and Rehabilitation Science in the UI Roy J. and Lucille A. Carver College of Medicine, found that a protein involved in muscle pain works in conjunction with the male hormone testosterone to protect against muscle fatigue.
Chronic pain and fatigue often occur together — as many as three in four people with chronic, widespread musculoskeletal pain report having fatigue; and as many as 94 percent of people with chronic fatigue syndromes report muscle pain. Women make up the majority of patients with these conditions.
To probe the link between pain and fatigue and the influence of sex, the UI team compared exercise-induced muscle fatigue in male and female mice with and without ASIC3 — an acid-activated ion channel protein that the team has shown to be involved in musculoskeletal pain.
A task involving three one-hour runs produced different levels of fatigue in the different groups of mice as measured by the temporary loss of muscle strength caused by the exercise.
Male mice with ASIC3 were less fatigued by the task than female mice. However, male mice without the ASIC3 protein showed levels of fatigue that were similar to the female mice and were greater than for the normal males.
In addition, when female mice with ASIC3 were given testosterone, their muscles became as resistant to fatigue as the normal male mice. In contrast, the muscle strength of female mice without the protein was not boosted by testosterone.
“The differences in fatigue between males and females depends on both the presence of testosterone and the activation of ASIC3 channels, which suggests that they are interacting somehow to protect against fatigue,” Sluka said. “These differences may help explain some of the underlying differences we see in chronic pain conditions that include fatigue with respect to the predominance of women over men.”
The study, which was published in the Feb. 28 issue of the American Journal of Physiology — Regulatory, Integrative and Comparative Physiology, indicates that muscle pain and fatigue are not independent conditions and may share a common pathway that is disrupted in chronic muscle pain conditions. The team plans to continue their studies and investigate whether pain enhances fatigue more in females than males.
“Our long-term goal is to come up with better treatments for chronic musculoskeletal pain,” Sluka said. “But the fatigue that is typically associated with chronic, widespread pain is also a big clinical problem — it leaves people unable to work or engage in social activities. If we could find a way to reduce fatigue, we could really improve quality of life for these patients.”
In addition to Sluka, the UI research team included Lynn Burnes, a research assistant and lead author of the study; Sandra Kolker; Jing Danielson; and Roxanne Walder. The study was funded in part by grants from the National Institute of Arthritis and Musculoskeletal and Skin Diseases.
An estimated nine million men and women in the United States live with myofascial pain syndrome, a condition marked by pain that permeates muscles in the neck, back and shoulders. The condition is difficult to diagnose and not entirely understood, but research studies indicate that a new imaging technology developed at Mayo Clinic holds promise for a definitive diagnosis and, perhaps eventually, new treatments for people who have the syndrome.
A Mayo Clinic study published in the November issue of the Archives of Physical Medicine and Rehabilitation shows that magnetic resonance elastography, or MRE, can provide images of the affected muscle with clarity and insight not possible with magnetic resonance imaging, or MRI. While an MRI uses a magnetic field and radio waves to create clear and detailed cross-sectional images of the body’s internal tissues and organs, an MRE measures the elasticity of tissue as it is gently vibrated.
“Additional research is necessary, but our findings in this pilot study provide a strong basis to suspect that MRE technology can identify changes in muscle tone and stiffness that could previously only be identified by physical examination by a physician or a therapist,” says Jeffrey Basford, M.D., Ph.D., a Mayo Clinic specialist in physical medicine and rehabilitation and an author of the study. “Prior to these findings, we did not have a good diagnostic test for myofascial pain syndrome.”
An MRE employs standard MRI equipment with a few modifications and works by measuring the wavelength of vibrations sent through the tissues. A vibrating metal plate is placed on the patient causing muscles to contract and stiffen. When this occurs, researchers can measure the elasticity of muscles and detect abnormal hardening of tissues, which in myofasical pain syndrome can cause pain.
The MRE technique is being applied to the diagnosis of other diseases, such as liver disease and could also be used to diagnose breast cancer and other tumors, which tend to be harder than the surrounding normal tissue.
Myofascial pain syndrome is sometimes confused with fibromyalgia, but the two conditions are clinically different. Fibromyalgia is a chronic condition typically characterized by widespread pain in muscles, ligaments and tendons, as well as fatigue and multiple tender points. Myofascial pain syndrome, is a more localized pain that is associated with trigger point tenderness. A trigger point is a small lump in a band of tight muscle that, when pressed, triggers a reproducible pattern of referred pain.
“In the past, myofasical pain syndrome has been very difficult to diagnose. These new findings may be the next step for a diagnosis and in the future may help to refine treatment options,” Dr. Basford says.
In some chronic cases of myofascial pain, combinations of physical therapy and trigger point injections are needed to relieve pain. In addition, the condition is sometimes treated with the “spray and stretch” technique, which involves spraying the muscle and trigger point with a coolant and then slowly stretching the muscle.
People who have the common chronic pain condition fibromyalgia often report that they don’t respond to the types of medication that relieve other people’s pain.
New research from the University of Michigan Health System helps to explain why that might be: Patients with fibromyalgia were found to have reduced binding ability of a type of receptor in the brain that is the target of opioid painkiller drugs such as morphine.
The study included positron emission tomography (PET) scans of the brains of patients with fibromyalgia, and of an equal number of sex- and age-matched people without the often-debilitating condition. Results showed that the fibromyalgia patients had reduced mu-opioid receptor (MOR) availability within regions of the brain that normally process and dampen pain signals — specifically, the nucleus accumbens, the anterior cingulate and the amygdala.
“The reduced availability of the receptor was associated with greater pain among people with fibromyalgia,” says lead author Richard E. Harris, Ph.D., research investigator in the Division of Rheumatology at the U-M Medical School’s Department of Internal Medicine and a researcher at the U-M Chronic Pain and Fatigue Research Center.
“These findings could explain why opioids are anecdotally thought to be ineffective in people with fibromyalgia,” he notes. The findings appear in The Journal of Neuroscience. “The finding is significant because it has been difficult to determine the causes of pain in patients with fibromyalgia, to the point that acceptance of the condition by medical practitioners has been slow.”
Opioid pain killers work by binding to opioid receptors in the brain and spinal cord. In addition to morphine, they include codeine, propoxyphene-containing medications such as Darvocet, hydrocodone-containing medications such as Vicodin, and oxycodone-containing medications such as Oxycontin.
The researchers theorize based on their findings that, with the lower availability of the MORs in three regions of the brains of people with fibromyalgia, such painkillers may not be able to bind as well to the receptors as they can in the brains of people without the condition.
Put more simply: When the painkillers cannot bind to the receptors, they cannot alleviate the patient’s pain as effectively, Harris says. The reduced availability of the receptors could result from a reduced number of opioid receptors, enhanced release of endogenous opioids (opioids, such as endorphins, that are produced naturally by the body), or both, Harris says.
The research team also found a possible link with depression. The PET scans showed that the fibromyalgia patients with more depressive symptoms had reductions of MOR binding potential in the amygdala, a region of the brain thought to modulate mood and the emotional dimension of pain.
The study subjects were 17 women with fibromyalgia and 17 women without the condition.
The senior author of the paper was Jon-Kar Zubieta, M.D., Ph.D., the Phil F. Jenkins Research Professor of Depression in the U-M Department of Psychiatry and a member of U-M’s Molecular and Behavioral Neuroscience Institute, Depression Center and Department of Radiology. Other authors were Daniel J. Clauw, M.D.; David J. Scott, Ph.D.; Samuel A. McLean, M.D., MPH; and Richard H. Gracely, Ph.D.
The research was supported by grants from the Department of the Army; the National Center for Research Resources, a component of the National Institutes of Health; and the NIH. Harris was supported by an NIH–National Center for Complementary and Alternative Medicine Grant. McLean was supported by an NIH grant.
Pregnant women with fibromyalgia (FM) experience significant pain, fatigue and psychological stress, symptoms that are often misdiagnosed or undertreated as a normal part of pregnancy, according to a pilot study by Karen M. Schaefer, D.N.Sc., R.N., assistant professor of nursing at Temple University’s College of Health Professions. Her research, the first to look at the impact of pregnancy on women with FM, was recently presented at the 2006 Association of Women’s Health, Obstetrics and Neonatal Nurses’ convention in Baltimore.
Fibromyalgia is a chronic condition commonly found in women that causes pain in the muscles and soft tissues of the body. Many sufferers feel weak from fatigue, and the condition, at its worst, can lead to disability.
“Until now, there was only anecdotal evidence suggesting that women with FM had a rougher time during pregnancy,” said Schaefer. “This data is the first step toward gathering hard evidence of FM effects on this group and will hopefully help us identify ways to reduce the impact of fibromyalgia during pregnancy.”
For this study, Schaefer recruited pregnant women with and without FM through an Internet announcement on a fibromyalgia Web site. Study subjects were between the ages of 29 and 31, in their third trimester, with no history of stillbirth and free of chronic illnesses other than FM.
The women were then mailed a questionnaire about fatigue, depression, pain and ability to function. A demographic form was also used to assess the number of painful areas in the body as well as age, marital status, education, hours slept and use of medication.
Schaefer’s results revealed that the pregnant women with fibromyalgia had a hard time functioning, felt more stiff and tired, and experienced pain in more body areas than women without FM.
“Most women with FM have trouble getting this condition properly diagnosed, let alone knowing where to turn for help once their condition is identified. We need to start looking at how FM affects all areas of these women’s lives and come up with ways to provide as much comfort and support as possible,” she said.
Schaefer, whose research focuses on women with chronic illness (fibromyalgia, lupus, ovarian cancer) is currently expanding her study to include a larger group of subjects.
GAINESVILLE, Fla.—The millions of Americans who suffer from fibromyalgia live with a two-edged sword: excruciating pain, accompanied by the doubts of many who dismiss it as a made-up illness invented by a troubled mind.
But researchers at the University of Florida and elsewhere are beginning to piece together clues that reveal the physical basis of the puzzling syndrome that causes severe fatigue and aches, and has defied easy diagnosis.
UF scientists have found an abnormal central nervous system reaction in those with fibromyalgia-the body magnifies ordinary repetitive stimulation into an experience of crippling pain.
“This is particularly important because it has been unclear if fibromyalgia was just an imagined illness or a real syndrome,” said Dr. Roland Staud, an associate professor of medicine at UF’s College of Medicine who also is affiliated with the UF Brain Institute. “We now have good evidence that shows that it’s not a psychological abnormality, butthat there is a neurological abnormality present.”
Staud, who presented his research findings at the annual meeting of the American College of Rheumatology last November, recently was awarded a National Institutes of Health grant worth nearly $800,000 to continue his studies for the next four years. Donald Price, a UFprofessor of oral and maxillofacial surgery, and Charles Vierck, a UF professor of neuroscience, are collaborating on the research. Their goal is to develop a better understanding of the condition, with an eye toward improving diagnostic tests and treatments.
An estimated 3.7 million people in the United States – primarily women who are diagnosed during their 30s and 40s – have fibromyalgia, according to the NIH. A chronic illness with no known cure, its cause also is not known. Researchers have theorized that an injury to the central nervous system or an infectious agent might be responsible for triggeringit in people who have inherited susceptibility. Symptoms include persistent and widespread musculoskeletal pain, fatigue and tenderness in the neck, spine, shoulders and hips.
Staud and colleagues found the central nervous system abnormality byconducting a series of repetitive stimulation tests on people with thesyndrome as well as healthy research participants. The tests involved repeatedly placing warm plates on their hands and arms. The healthy participants felt the sensation but did not report it as pain.
For those with fibromyalgia, however, the sensation would magnify with each repetition into an experience of crippling and unbearable pain.
“When a sensation signal reaches the spinal cord, the signal can be omitted, changed or augmented,” Staud said. “If it is augmented, then something that is innocuous, such as pressure on the skin, can then be perceived as a painful stimulus.”
Jessica LeMay, one of Staud’s patients, has been battling fibromyalgia since 1993. The 30-year-old Lake City resident said the pain starts in one area and usually spreads, sometimes becoming overwhelming.
“I imagine if someone had taken a baseball bat and beaten me with it,that’s got to be what it feels like,” she said. “Depending on the day, I’ll just move out of the way if someone tries to touch me.”
The pain of fibromyalgia often interferes with a person’s working life.
“These are people who are diagnosed in their productive years. Many have personal or professional problems adjusting to the pain experience,” Staud said. “The illness makes some people feel dysfunctional because they can’t do the activities they once did.”
The condition can worsen from stress and inadequate sleep, Staud said. Because living with fibromyalgia often causes stress, and pain makes sleeping difficult, a vicious cycle develops.
LeMay said many people dismiss her condition, not understanding the “huge difference” between her severe fatigue and the healthy person’s occasional tiredness.
“When this fatigue would come about, it’s almost like a weight being dropped on you, and you can’t function anymore,” she said.
LeMay said she is hopeful that Staud’s research will lead to more effective treatment for fibromyalgia patients and better understanding by the general public.
“In our society, you either get better or you die, and fibromyalgiapatients don’t do that,” she said. “We don’t fit in the mold, so people don’t know what to do with us.”
