Small Fiber Neuropathy with Inadequate Response to Medical Therapy: Diagnosis and Treatment of Small Fiber Neuropathy

Abstract

Small-fiber neuropathies are a heterogeneous group of disorders affecting thinly myelinated Aδ and unmyelinated C fibers. Patients generally present with neuropathic pain, while dysesthesia, allodynia, pain, burning sensations, and cold sensations are frequently present in a length-dependent pattern. Additional autonomic features of the gastrointestinal, urinary, or cardiovascular systems are frequently observed. Deep-tendon reflexes and nerve conduction tests yield normal results. Skin biopsy is useful for the diagnosis, and can demonstrate the loss of intraepidermal nerve fibers in small-fiber neuropathy and has a diagnostic sensitivity of 80%. Although many causes of small-fiber neuropathy have been reported, the cause remains unknown in 30-50% of the cases. Treatment is directed at the underlying etiology and is supported with symptomatic treatment.