Small fiber neuropathies

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By Eduardo Adonias De Sousa MD

The task of confirming a diagnosis of suspected small fiber sensory neuropathy can be difficult. Dr. De Sousa of Thomas Jefferson University presents a basic overview of the subject. Key diagnostic elements are history and physical examination in combination with normal electrodiagnostic tests. Laboratory tests may reveal associated disorders, although some cases are idiopathic. Punch skin biopsies may show reduced intraepidermal nerve fiber density. Subclinical autonomic involvement may be detected with additional tests. There is no treatment for numbness. Neuropathic pain and dysesthesias may be treated with medications and nonpharmacological therapies.

Key Points

  • Small fiber sensory peripheral neuropathies often present with length-dependent numbness or pain due to abnormal somatic unmyelinated or small myelinated nerve function.
  • Important associated conditions include diabetes, toxic agents, Sjogren syndrome, and amyloidosis.
  • There is no consensus on a gold standard diagnostic test, so the diagnosis is based on history, clinical examination, normal electrodiagnostic testing, and supportive laboratory evidence, including intraepidermal nerve fiber density analysis on skin biopsy.
  • Autonomic tests may be abnormal, even in the absence of overt autonomic symptoms.
  • There is no treatment for numbness, but there are pharmacologic and nonpharmacologic treatments for neuropathic pain.