Small-Fiber Polyneuropathy ID'd in Fibromyalgia Cases
Distal-leg biopsies from 41 percent of 27 patients with fibromyalgia are diagnostic for SFPN
MONDAY, Aug. 5 (HealthDay News) -- Some patients diagnosed with fibromyalgia may actually have small-fiber polyneuropathy (SFPN), according to a study published online June 7 in PAIN.
Anne Louise Oaklander, M.D., Ph.D., from Harvard Medical School in Boston, and colleagues analyzed SFPN-associated symptoms, signs, and pathological and physiological markers in 27 patients with fibromyalgia (who satisfied the American College of Rheumatology criteria and had documented evidence of a physician's diagnosis) and in 30 normal matched controls.
The researchers found that 41 percent of distal-leg neurodiagnostic skin biopsies from subjects with fibromyalgia and 3 percent from controls were diagnostic for SFPN. Compared with controls, patients with fibromyalgia had significantly higher Michigan Neuropathy Screening Instrument and Utah Early Neuropathy Scale scores. The prevalence of abnormal autonomic-function testing was equal between the groups. Glucose tolerance tests were normal from 13 subjects with fibromyalgia and SFPN-diagnostic biopsies, but eight, two, and one patient, respectively, had dysimmune markers, hepatitis C serologies, and apparent genetic causality.
"These findings suggest that some patients with chronic pain labeled as fibromyalgia have unrecognized SFPN, a distinct disease that can be tested for objectively and sometimes treated definitively," the authors write.