Submitted by: Niranjan Singh, MD
Edited by: Vishwajit Hegde, MD
Oaklander AL, Mills AJ, Kelley M, et al. Peripheral neuropathy evaluations of patients with prolonged long COVID. Neurol Neuroimmunol Neuroinflamm
. 2022;9(3):e1146. Published 2022 Mar 1. doi:10.1212/NXI.0000000000001146
In this retrospective analysis, authors analyzed cross-sectional and longitudinal data from patients with World Health Organization (WHO)-defined long COVID without prior neuropathy history or risks who were referred for evaluation of neuropathy.
The study found that small fiber neuropathy after mild COVID-19 was most common beginning within a month of disease onset. The study is suggestive of infection-triggered immune dysregulation as a common mechanism.
Among 17 patients analyzed by the study group, 16 had mild COVID-19. Among the patients with mild COVID-19, 10/16 of lower leg skin biopsies pathologically confirmed small fiber neuropathy. The initial SFN scores were abnormal - reduced to 40.7%. Distal muscle weakness, absent ankle reflex, abnormal distal pinprick, and vibrations were noted. Treatment was comprised of corticosteroids and/or IV immunoglobulin (IVIG). Response to the treatment was variable.
: Reports of peripheral neuropathy, mononeuritis multiplex, brachial plexitis, cranial neuropathy, and orthostatic intolerance have been reported in patients with COVID-19. Patients with mild or asymptomatic COVID-19 or patients who recovered from more severe infections continue to present with unexplained fatigue/exertional intolerance, dysautonomia symptoms, and sensory concerns. Those patients may need workup for small fiber neuropathy including skin biopsy and treatment with immunomodulation.
Though the study has a small number of patients, small fiber neuropathy appears to be the most prevalent in this group with long COVID-19. Some patients treated with steroid and most patients treated with sustained IVIG perceived improvement. A spontaneous recovery was also documented. This supports the hypothesis that some long COVID-19 symptoms reflect underlying small fiber neuropathy.
The current study neither confirms causality nor the clinical significance of magnitude of any association. More research is required.
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