Small fibers, large impact: Quality of life in small-fiber neuropathy

Introduction: The impact of small-fiber neuropathy (SFN) on patients' quality of life (QOL) has not been studied extensively. Our aim was to determine the impact of SFN on QOL and examine possible determinants. Methods: We exam- ined a total of 265 patients diagnosed with SFN. The SFN Symptoms Inventory Questionnaire (SFN-SIQ), the pain Visual Analog Scale (VAS), and the generic SF-36 Health Survey were assessed. Regression studies were undertaken to evalu- ate determinants of functioning. Results: SFN patients demon- strated a severe overall reduction in QOL. The biggest deficits were in Role Functioning-Physical, Body Pain, and Physical Component Summary (PCS) scores. VAS scores, changed sweating pattern, dry mouth, and age were the strongest pre- dictors for PCS, explaining 32% of the QOL decrease. Conclu- sions: SFN leads to a reduction in overall QOL. The presence of pain and some autonomic symptoms explained only a small portion of the findings. Muscle Nerve 000:000-000, 2013 Small-fiber neuropathy (SFN), a disorder of thinly myelinated A-d and unmyelinated C fibers, is char- acterized by chronic and severe complaints, such as neuropathic pain and autonomic symptoms. SFN is associated with various disorders, such as metabolic (diabetes mellitus), infectious (human immunodeficiency virus), inflammatory (Sj€ ogren's syndrome), and genetic (Fabry disease) diseases, but the cause is often idiopathic. The incidence and prevalence of SFN is unknown, 1,2 but probably not rare. In patients with diabetes mellitus, for example, a disease with increasing incidence and prevalence, 3 an estimated 16-20% have painful neuropathy. 4,5 This has been largely attributed to small-fiber involvement. 6