Nearly half of the fibromyalgia patients in a small study were found to have damaged nerve fibers in their skin, according to researchers at Massachusetts General Hospital. The findings, published in the journal Pain, could lead to better treatment for patients who have the chronic pain disorder.
Researchers followed 27 adult fibromyalgia patients and 30 healthy subjects. In addition to nerve damage, they found signs of a disease known as small-fiber polyneuropathy (SFPN) in some of the fibromyalgia patients. Fibromyalgia has no known cause, but SFPN is caused by medical conditions such as diabetes and glucose intolerance. It is often treated with anti-depressants, anticonvulsants or opioid painkillers.
“This provides some of the first objective evidence of a mechanism behind some cases of fibromyalgia, and identifying an underlying cause is the first step towards finding better treatments,” lead author Anne Lousie Oaklander, director of the Nerve Injury Unit at Massachusetts General Hospital.
Fibromyalgia is a poorly understood disorder that is characterized by deep tissue pain, fatigue, headaches, depression and lack of sleep. Many of the symptoms mirror those of SFPN, a form of peripheral neuropathy that causes severe pain that usually originates in the hands or feet.
Thirteen of the 27 fibromyalgia patients in the study had a notable reduction in nerve fiber density, indicating SFPN. While diabetes is a common cause of SFPN, none of the patients were diabetic. Over half of the patients showed signs of an immune system dysfunction.
“Until now, there has been no good idea about what causes fibromyalgia, but now we have evidence for some but not all patients. Fibromyalgia is too complex for a ‘one size fits all’ explanation,” said Oaklander.
“The next step of independent confirmation of our findings from other laboratories is already happening, and we also need to follow those patients who didn’t meet SFPN criteria to see if we can find other causes.”
In contrast to the Massachusetts study, researchers at Albany Medical College and Integrated Tissue Dynamics recently reported that fibromyalgia patients had more, not less, nerve fibers in the blood vessels in the palms of their hands. The excess nerve fibers appeared to disrupt the normal flow of blood through the hands and possibly throughout the body, according to a study published in Pain Medicine.