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Physiologic and Cognitive Variables Responsible for Pain Associated With Fibromyalgia: PAINWeek

By Kristina R. Anderson

LAS VEGAS, NV -- September 11, 2007 -- The still-mysterious affliction of fibromyalgia may indeed be largely in the patient's head, but as a result of a genuine malfunction of part of the brain and not a figment of the long-suffering patient's imagination, a pair of experts said Saturday at PAINWeek 2007, the national conference on pain for frontline practitioners.

Current research, they said, was homing in on the baffling ailment in the area of the brain's hippocampus and the effect it has on the many symptoms connected to fibromyalgia.

"The hippocampus acts as a control for proper and effective sleep and the processing of stress, which are two areas that we as researchers are eyeing as primary triggers for fibromyalgia," said Patrick B. Wood, MD, Assistant Clinical Professor Departments of Family Medicine, Psychiatry and Anesthesiology, Louisiana State University Health Sciences Center, Shreveport, Chief Medical Officer, Angler Biomedical Technologies, Louisiana, United States.

The hippocampus is the thermostat that regulates tonic dopamine and, as a result, it gauges a person's physical reaction to stressful situations. Dr. Wood described the hippocampus as being particularly vulnerable to functional changes brought on by stress. And when those changes disrupt dopamine regulation, the body's ability to ignore pain and "cool down" during and after a stressful situation is switched off. The result is the patient remains stuck in a situation of rawness and a state of hyper-alertness where the slightest touch and pressures can cause pain. "Suddenly, all of your filters are switched off," explained Dr. Wood.

Rheumatologist Andrew J. Holman, MD, Assistant Clinical Professor Medicine, University of Washington, Seattle, Washington, United States, told the audience that fibromyalgia appeared to have roots in sleep disturbances that prevented the patient from reaching the deep stage-4 stage of sleep. "Fibromyalgia patients are not reaching stage 4 sleep," he said.

Dr. Holman, who said he sees two or three new fibromyalgia patients per day at his practice, pointed to the 1970's landmark study by Harvey Modolfsky, MD of the University of Toronto(1). In the study, the protocol created sleep disturbances that resulted in subjects developing symptoms of fibromyalgia. Modolfsky hypothesized that the sleep disturbances were a result of serotonin metabolism

A similar experiment mentioned from the Brooke Army Medical Center(2) failed to recreate the results, but Holman said a key difference in the methods used to rouse the subjects could explain the different results in those two studies.

The sleep of subjects in the Brooke Army study was disturbed relatively gently with soft music of the patient's choice while Moldofsky used a considerably more jarring computer-generated noise to "startle" snoozing volunteers from deep sleep to light sleep.

Differences aside, Dr. Holman said it is clear that fibromyalgia patients do not attain stage 4 sleep. "And it doesn't matter how physically fit they are," he added. "Specific stage 4 sleep deprivation induced fibromyalgia symptoms through alpha wave intrusion into delta wave sleep."

The symptoms of fibromyalgia are wide ranging and mysterious enough that it rates as a syndrome, which Drs. Holman and Wood said can lead to difficulty in making a diagnosis, and there is a tendency among some caregivers to dismiss a patient's numerous complaints as a singular malady, such as migraines, or as a pure reaction to everyday stress.

Risk factors for fibromyalgia include:

· adverse early life events, such as neglect, abuse or death of a parent;
· psychiatric disturbances, such as post-traumatic stress disorder, recurrent major depression, generalised anxiety and/or panic disorder;
· trauma -- physical and/or emotional;
· systemic infection;
· personality type A+ and/or axis II disorders;
· chronic stress.

Dr. Wood said statistics show that more than half of depressed patients presenting in a primary care clinical setting complained of pain, fatigue, headache, neck, back or joint pain, memory difficulties, cough and muscle aches. Associated symptoms include restless legs, irritable bowels, difficulty concentrating, headaches, urinary problems, painful menses, allergic symptoms, dizziness, cold sensitivity, numbness/tingling, anxiety and depression. Some physicians have concluded that the patient presenting with myriad symptoms had nothing physically wrong with them and were candidates for psychiatric treatment.

At the same time, Dr. Wood noted, many fibromyalgia patients did not consider themselves to be clinically depressed and may not even meet the criteria for a diagnosis of depression. "They're not depressed. A lot of them, however, are very discouraged," he said.

Physicians, particularly those in a primary care setting, are urged to do an in-depth physical workup on patients presenting with a list of symptoms. "We know there are multiple neuroendocrine disturbances and an impaired growth hormone secretion," Dr. Wood said. "There is also a sympathetic hyperactivity and there are overactive corticotropin-releasing hormone neurons."

"You can think there is nothing wrong with these patients, but then you scratch the surface and realize that everything is wrong with these patients," he said.


REFERENCES:
1. Older SA et al. The effects of delta wave sleep interruption on pain thresholds and fibromyalgia-like symptoms in healthy subjects; correlations with insulin-like growth factor I. J Rheumatol. 1998 Jun:25(6):1180-1186.
2. Moldofsky H. Musculoskeletal symptoms and non-REM sleep disturbance in patients with "fibrositis syndrome" and healthy subjects. Psychosom Med. 1975 Jul-Aug;37(4):341-351.


[Presentation title: Physiologic and Cognitive Variables Responsible for the Pain Associated With Fibromyalgia.]

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