As corneal confocal microscopy is not readily available, ankle skin biopsy remains the recommended method of diagnosing SFPN. Samples taken during an office visit can be mailed to an accredited lab for testing.
“If skin biopsy reveals small fiber polyneuropathy, medical causes should be looked for because disease-modifying treatments, and even cures, may be available,” Dr. Oaklander advised, noting that symptoms may improve with management of underlying conditions, such as autoimmune disease, hepatitis, malignancy, diabetes, or prediabetes.
For patients with fibromyalgia and diagnosed SFPN, medications such as serotonin norepinephrine reuptake inhibitors (SNRIs), tricyclics, gabapentin, pregabalin, and duloxetine may be effective.1,
“If sodium channelopathy can be confirmed as a cause of fibromyalgia, new, more specific sodium channel blockers may be developed to treat fibromyalgia,” Dr. Martinez-Lavin pointed out.
Although the role of small fiber neuropathy in fibromyalgia is still not entirely clear, researchers are now beginning to unravel details about this complex condition. A demonstrable pathology has been found in about half of patients, and a cause is being actively pursued for the other half. Once causes are identified, better treatments often follow — all of which mean a brighter future for fibromyalgia patients.
1. Bottom Line/Health, Fibromyalgia: New Research Helps Unravel the Mystery, http://bottomlinehealth.com/fibromyalgia-new-research-helps-unravel-the-mystery/
2. Pain Research Forum, Multiple Studies, One Conclusion: Some Fibromyalgia Patients Show Peripheral Nerve Pathologies, http://www.painresearchforum.org/news/33529-multiple-studies-one-conclusion-some-fibromyalgia-patients-show-peripheral-nerve
3. Ramirez M, Martinez-Martinez LA, Hernandez-Quintela E, et al. Seminars in Arthritis and Rheumatism, Small fiber neuropathy in women with fibromyalgia. An in vivo assessment using corneal confocal bio-microscopy. Semin Arthritis Rheum. 2015 Oct;45(2):214-9. doi: 10.1016/j.semarthrit.2015.03.003. Epub 2015 Mar 19.
4. Albrecht PJ, Hou Q, Argoff CE, Storey JR, Wymer JP, Rice FL. Excessive peptidergic sensory innervation of cutaneous arteriole-venule shunts (AVS) in the palmar glabrous skin of fibromyalgia patients: implications for widespread deep tissue pain and fatigue. Pain Med. 2013 Jun;14(6):895-915. doi: 10.1111/pme.12139.
5. Oaklander AL, Herzog ZD, Downs HM, Klein MM. Objective evidence that small-fiber polyneuropathy underlies some illnesses currently labeled as fibromyalgia. Pain. 2013 Nov;154(11):2310-6. doi: 10.1016/j.pain.2013.06.001.