Many patients labeled as having fibromyalgia may actually be suffering from disease known as small-fiber polyneuropathy (SFPN), according to a new study. Although fibromyalgia is a recognized medical condition, the biological causes are still unknown and there is still no single cure. SFPN on the other hand does have known causes related to certain medical conditions, and can even be cured in some cases.
Researchers from the Massachusetts General Hospital studied a possible link between the two conditions in a new study. They found that almost of half of patients with fibromyalgia showed signs of SFPN.
“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,” said co-author of the paper, Anne Louise Oaklander, MD, PhD, of the Nerve Injury Unit at the Massachusetts General Hospital.
The study included 27 patients with fibromyalgia and 30 healthy controls. The researchers performed a variety of tests to diagnose SFPN including: skin biopsies to assess the number of nerve fibers in their lower legs; tests of autonomic functions like blood pressure, heart rate, and sweating; and physical examinations and questionnaires to evaluate nerve damage, or neuropathy.
Nearly half of fibromyalgia patients had significantly reduced nerve fiber density, abnormalities on autonomic functions tests, or both, suggesting they had SFPN. While none of the patients had diabetes, a common cause of SFPN, more than half had dysfunctional immune systems.
The findings suggest that some cases of fibromyalgia may be caused by SFPN, although there is still no “one-size fits all” explanation for the condition, pointed out Dr. Oaklander. Another recent study suggested that fibromyalgia may also be related to other abnormalities in sensory nerves fibers in the skin.
Oaklander AL, et al. Objective evidence that small-fiber polyneuropathy underlies some illnesses currently labeled as fibromyalgia. Pain 2013; doi 10.1016/j.pain.2013.06.001.
- Tags: fibromyalgia