Trial Report Case-Control Study of Individuals With Small Fiber Neuropathy After COVID-19, 2024, McAlpine

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https://www.neurology.org/doi/10.1212/NXI.0000000000200244

Case-Control Study of Individuals With Small Fiber Neuropathy After COVID-19

Lindsay McAlpine, MD https://orcid.org/0000-0003-3652-5645, Adeel S. Zubair, MD https://orcid.org/0000-0002-9809-7888, Phillip Joseph, MD https://orcid.org/0000-0001-9299-8629, and Serena Spudich, MD,
May 2024 issue
11 (3)
https://doi.org/10.1212/NXI.0000000000200244

Abstract

Objectives
To report a case-control study of new-onset small fiber neuropathy (SFN) after COVID-19 with invasive cardiopulmonary exercise testing (iCPET). SFN is a critical objective finding in long COVID and amenable to treatment.

Methods
A retrospective chart review was conducted on patients seen in the NeuroCOVID Clinic at Yale who developed new-onset SFN after a documented COVID-19 illness. We collected demographics, symptoms, skin biopsy, iCPET testing, treatments, and clinical response to treatment or no intervention.

Results
Sixteen patients were diagnosed with SFN on skin biopsy (median age 47, 75% female, 75% White). 92% of patients reported postexertional malaise characteristic of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and 7 patients underwent iCPET, which demonstrated neurovascular dysregulation and dysautonomia consistent with ME/CFS. Nine patients underwent treatment with IVIG, and 7 were not treated with IVIG. The IVIG group experienced significant clinical response in their neuropathic symptoms (9/9) compared with those who did not receive IVIG (3/7; p = 0.02).

Discussion
Here, we present preliminary evidence that after COVID-19, SFN is responsive to treatment with IVIG and linked with neurovascular dysregulation and dysautonomia on iCPET. A larger clinical trial is indicated to further demonstrate the clinical utility of IVIG in treating postinfectious SFN.

Classification of Evidence
This study provides Class III evidence. It is a retrospective cohort study.