Small fiber neuropathy in the post-COVID condition and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Clinical significance and diagnostic challe

SWAlexander

Senior Member
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2,101

Abstract​


Background​


Patients with post-COVID condition (PCC) and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) experience symptoms potentially associated with small fiber neuropathy (SFN).

Methods​


A sample of 90 participants, comprising 30 PCC patients, 30 ME/CFS patients, and 30 healthy controls (HC), matched by sex and age, was assessed. Neuropathic, autonomic, and fatigue symptoms were measured with TaskForce Monitor, the Sudoscan, heat and cold evoked potentials, In Vivo Corneal Confocal Microscopy (IVCCM), and specialized questionaries.

Results​


PCC and ME/CFS patients demonstrated significantly higher levels of autonomic symptoms (H = 39.89, p < 0.001), neuropathic symptoms (H = 48.94, p < 0.001), and fatigue (H = 49.29, p < 0.001) compared to HC. Quantitative sensory testing revealed significant differences in heat detection thresholds between PCC patients and HC (F = 4.82; p < 0.01). Regarding corneal small fiber tortuosity, there were statistically significant differences between patients and HC (F = 6.80; p < 0.01), indicating pathological responses in patients. Small fiber tortuosity in IVCCM was identified as the main discriminator between patients and HC (AUC = 0.720; p < 0.01).

Conclusion​


PCC and ME/CFS patients demonstrated sensory SFN, as evidenced by impaired heat detection and increased tortuosity of small fibers in the central corneal subbasal plexus. The findings underscore the importance of a multimodal approach to comprehensively detect and characterize SFN. This study provides valuable scientific insights into the neuropathic manifestations associated with these conditions.
https://onlinelibrary.wiley.com/doi/10.1111/ene.70016
 

cfs since 1998

Senior Member
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784
I am starting to be think that ME/CFS _IS_ small fiber neuropathy, perhaps a type that preferentially affects nerve fibers that innervate blood vessels rather than the painful skin nerve degeneration that diabetics experience.

Exertion intolerance/PEM is often thought of as unique to ME/CFS (heck the ICC is trying to rename it Systemic Exertion Intolerance Disease) but it isn't. It's also a symptom of SFN.

From "Biomarkers in small fiber neuropathy" (Chan et. al. 2022):

SFN-biomarkers.png
 

Wishful

Senior Member
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6,194
Location
Alberta
I read the wiki for SFN, and it doesn't seem to fit my ME. My temporary remission test: would someone with SFN be able to switch in or out of that state over the span of minutes?
 
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