Small Fibre Neuropathy and Post-COVID-19 Pain: An In-depth Study
Pietro Falco1, Daniel Litewczuk2, Giulia Di Stefano2, Eleonora Galosi2, Caterina Leone2, Gianfranco De Stefano2, Giuseppe Di Pietro2, Andrea Truini2
1Department of Human Neuroscience, Sapienza University of Rome, 2Sapienza University of Rome
Objective:

In this case-control study, our primary objective was to detect small fiber neuropathy (SFN) among patients who experienced sensory symptoms and pain following the acute phase of COVID-19. Additionally, we sought to investigate potential risk factors associated with the development of SFN and to delve into the mechanisms contributing to the occurrence of post-COVID-19 pain.

 

 

Background:
Many post-COVID-19 patients commonly report sensory symptoms and pain, raising questions about the potential role of SFN. Due to limited existing research, comprehensive small fiber assessments are lacking, leaving the question of whether small fiber neuropathy is the primary cause of post-COVID-19 pain unresolved.
Design/Methods:

To definitely diagnose SFN, we collected clinical data and investigated quantitative sensory testing (QST) and skin biopsy in 26 selected patients with painful post COVID-19 conditions. We also screened 100 previously ill COVID-19 survivors, selecting 30 control participants without any post COVID-19 neurological symptoms and 33 patients with painless post COVID-19 symptoms. Then, we compared the main demographic and clinical variables between groups.

Results:

Among the 26 patients with painful post-COVID-19 conditions, 12 exhibited clinical sensory signs and abnormalities in skin biopsy and/or QST results, consistent with a diagnosis of SFN. In our patients, demographic and clinical data (including COVID-19 severity) were comparable to those of previously ill COVID-19 survivors without neurological symptoms and to patients with painless post COVID-19 symptoms. The most frequent QST sensory profile among patients with SFN was mechanical hyperalgesia.

Conclusions:

Our study showed that SFN is relatively common in patients suffering from painful post COVID-19 condition; in our patients, however, this specific post COVID-19 complication was unrelated to demographic and clinical variables related to COVID-19, highlighting the need to screen this population for the presence of SFN, regardless of COVID-19 severity or specific risk factors. Moreover QST data suggests  that pain might predominantly reflect central sensitization phenomena.

10.1212/WNL.0000000000204847