Diagnosing Small Fiber Neuropathy

Tests to determine if you might have small fiber neuropathy

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    Clinical Examination and Symptoms

    According to Ezekiel Fink (UCLA) clinical examinations can find:
    • Stocking-glove distribution - issues start from the feet and hands upwards
    • Allodynia - touch and mild sensations produce pain
    • Hyperalgesia - hypersensitivity to pinpricks
    • Reduced sensitivity to pinpricks and heat sensations
    • Reduced sensitivity to vibration at the toes
    • Motor strength, tendon reflexes, and balance are fine.
    Fink reports that SFN can produce a wide variety of symptoms including painful sensations (burning pain, numbness, lancing pain, tingling), dry eyes, dry mouth, orthostatic intolerance, constipation bladder problems, sexual problems, problems sweating, dry, shiny, discolored skin.

    Do Your Symptoms Match?
    Diagnostic Tests

    According to Neuropathy Commons, a website produced by Anne Oaklander, the researcher and doctor who uncovered the small fiber neuropathy (or polyneuropathy) in fibromyalgia, three types of tests are recommended by the American Academy of Neurology or the European Academy of Neurology: skin biopsy, autonomic function testing and nerve biopsy.

    Skin Biopsies

    Skin biopsies are safe and easy to do (any MD can do them) but not enough doctors know about them. They require only a small section of skin (3 mm) and leave minimal scarring. The number of small nerves in the biopsy are quantified and compared to norms. Neuropathy Commons contains a list of doctors across the world who perform skin biopsies here.

    Autonomic Function Testing

    Autonomic function testing includes a battery of tests that determine if your autonomic nerves are functioning properly. The Mayo Clinic lists breathing, tilt table, sweat gland (sudomotor), gastrointestinal and other tests. Quantitative sensory testing can also be done.

    Nerve biopsy

    Nerve biopsies are older procedures done only at specialized centers.

    Corneal Tests

    Corneal tests are apparently not recommended (yet) by the AAN but non-invasive corneal tests have shown up in research studies.
    More information

    Check out Health Rising's blogs on Small Fiber Neuropathy and Fibromyalgia