Scans Document Fibromyalgia Pain
NEW YORK (Reuters Health) - Brain scans of people with fibromyalgia
offer the first hard evidence of what patients already know: Their
pain is real and their threshold for tolerating it is substantially
lower than that of most individuals.
"When patients with fibromyalgia tell us that they're tender, that
they're experiencing pain at a much lower level than people without
the condition, they are in fact experiencing that pain," said Dr.
Daniel Clauw, a professor of medicine at the University of Michigan
Medical Center in Ann Arbor.
"This is the first neurobiological evidence of the veracity
of their pain," he told Reuters Health.
Fibromyalgia affects an estimated 2% to 4% of the population,
mostly women. Patients commonly report feeling tenderness, stiffness
and sometimes unbearable pain in various areas of the body. They
also may suffer from fatigue, depression and gastrointestinal
problems. Some doctors without expertise in fibromyalgia have
dismissed patients' complaints because there have been no documented
physical signs of the disorder.
"I hope this study helps convince physicians that this is a
real condition," Clauw said.
In the new report, published in a recent issue of Arthritis
& Rheumatism, Clauw and colleagues studied 16 people who had been
diagnosed with fibromyalgia and 16 healthy people who had not
(the "control" group). All underwent a type of detailed brain
scan known as functional magnetic resonance imaging (fMRI) while
an instrument intermittently applied different levels of pressure
to their left thumbnail.
When all study participants received the same level of mild
pressure, blood flow increased much more in the brains of patients
with fibromyalgia than among those in the control group. The increased
blood flow--which is a "surrogate measure" for nerve activity--occurred
in areas of the brain known to be associated with pain, Clauw
In addition, when study participants were subjected to different
levels of pressure, fibromyalgia patients reported pain at half
the level of pressure that caused the same feelings of pain among
the healthy controls, results showed.
Clauw said the findings suggest that something is awry with
the way the central nervous system processes painful stimuli in
fibromyalgia patients. Future research should be aimed at identifying
the problem and working to develop better treatments, he added.
SOURCE: Arthritis & Rheumatism 2002;46:1333-1343.
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