REVERSIBLE SMALL FIBER NEUROPATHY DUE TO VITAMIN B12 DEFICIENCY
DOI:
https://doi.org/10.56238/arev8n5-023Keywords:
Small Fiber Neuropathy, Polyneuropathy, Pain-Related Evoked PotentialsAbstract
Small fiber neuropathy (SFN) involves dysfunction of thinly myelinated Aδ fibers and unmyelinated C fibers. Vitamin B12 deficiency is an uncommon but potentially reversible etiology. To describe a patient with SFN secondary to vitamin B12 deficiency with clinical and neurophysiological reversibility after replacement therapy, and to highlight the role of pain-related evoked potentials (PREP). A 63-year-old woman with no family history of neurological disease presented with hand paresthesia and burning pain in the lower limbs for one year. PREP obtained were absent. Serum vitamin B12 level was 111 pg/mL. A diagnosis of SFN due to vitamin B12 deficiency was established and replacement therapy was initiated. At follow-up, vitamin B12 level increased to 304 pg/mL, and PREP responses normalized, indicating successful treatment. This case underscores the importance of identifying the underlying etiology in patients with SFN symptoms. Recognition and treatment of vitamin B12 deficiency led to resolution of clinical and neurophysiological abnormalities. PREP represent a non-invasive, reliable, and cost-effective electrophysiological technique for evaluating Aδ-fiber function and may aid in both diagnosis and follow-up of small fiber dysfunction in systemic neuropathies.
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