This new understanding of fibromyalgia will hopefully lead to better treatments, doctors and researchers say.
Fibromyalgia affects 1% to 5% of Americans, mainly women, but until recently, scientists had no idea what might be causing its severe and mysterious pains. For decades, doctors told patients their agony was imaginary, the result of emotional hysteria, not a physical ailment.
But this year, researchers finally began to get a handle on the condition.
"What's happened is in 2013 there's been this absolute explosion of papers," says neurologist Anne Louise Oaklander at Massachusetts General Hospital in Boston. "The whole view on this has shifted."
Oaklander published two studies this year showing that half or more of the cases of fibromyalgia are really a little-known condition affecting the nerves. People with this small-fiber neuropathy get faulty signals from tiny nerves all over the body, including internal organs, causing an odd constellation of symptoms from pain to sleep and digestive problems that overlap with symptoms of fibromyalgia.
Neuroscientist Frank Rice and a team based at Albany Medical College also discovered that there are excessive nerve fibers lining the blood vessels of the skin of fibromyalgia patients — removing any doubt that the condition is physically real.
These fibers in the skin can sense blood flow and control the dilation and constriction of vessels to regulate body temperature, Rice says, as well as direct nutrients to muscles during exercise. Women have more of these fibers than men, he says, perhaps explaining why they are much more likely to get fibromyalgia.
"Blood vessel nerve fibers are an important target that haven't been in our line of thinking to date in chronic pain conditions," says Rice, now president and chief scientist at Integrated Tissue Dynamics LLC, a biotechnology research company in Rensselaer, N.Y.
In recent years, scans of patients with fibromyalgia have revealed brain changes associated with pain, but the new research suggests these are a symptom rather than the cause of the condition.
This new understanding of fibromyalgia will hopefully lead to better treatments, Rice and Oaklander say.
Right now, most people are treated with the antidepressants Cymbalta made by Eli Lilly, or Savella by Forest Pharmaceuticals, or with Lyrica, a seizure medication from Pfizer — which have all been federally approved for use in fibromyalgia.
But these drugs have side effects and don't help everyone.
"We're looking now to understand more about other features of the pathology that might lead to a more targeted approach and less of a shotgun that causes side effects," says Rice, also an adjunct professor at the University at Albany, State University of New York.
The trigger for fibromyalgia is still a mystery, although stressful events in patients' past have been thought to play a role.
Rheumatologist Richard Chou says there is some preliminary evidence that the nerve damage is caused by the immune system.
"We're hoping some day we'll be able to say exactly how your immune system is causing damage to the sensory nerves that results in fibromyalgia pain," says Chou, an assistant professor at the Geisel School of Medicine at Dartmouth in New Hampshire. Researchers don't yet know whether the pain causes the other problems of fibromyalgia — disrupting sleep, for instance — or whether both pain and sleep disturbances share the same cause.
Fibromyalgia's constellation of symptoms is very similar to those of chronic fatigue syndrome and Gulf War syndrome, which Oaklander's group also studies. "If someone has more of one symptom than another they might call it one thing, like chronic fatigue, but it's not clear that these are different," Oaklander says.
She says researchers still have a lot to learn about these conditions, but scientists are taking them more seriously and making real progress for the first time.
Carolyn DiSilva of Maynard, Mass., one of Oaklander's patients, says she was stunned to learn that she had small-fiber neuropathy caused by an overactive immune system, instead of fibromyalgia.
"I think a lot of people, they get a blanket diagnosis as fibromyalgia because doctors don't know what's wrong with them," says DiSilva, 47, who has suffered from unexplained pains for about 14 years. The non-stop agony and the pins and needles that plagued her for hours at a time forced her to give up her work as a hair stylist, she says.
Understanding what's causing her pain has helped her, she says, because doctors and others take her problems seriously, instead of dismissing her as they used to do.
And now that it's clear DiSilva has an immune problem, Oaklander has put her on intravenous immunoglobulin treatments — instead of conventional fibromyalgia therapy — which seem to be making a profound difference in her health.
DiSilva says her pain has dropped from a 10 on a 10-point scale to about a 4.
"I always hope that someday I'll wake up with no pain, but I'm so grateful that I've come this far."