cfs since 1998
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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11087026/
"Case-Control Study of Individuals With Small Fiber Neuropathy After COVID-19"
My summary:
Yale School of Medicine Department of Neurology found Small Fiber Neuropathy in Post-COVID-19 patients, most of them having had "mild" COVID19. Patients exhibited PEM, dysautonomia, and other ME/CFS symptoms. SFN was diagnosed by skin punch biopsy. Some, but not all patients were positive for sensory neuropathy autoantibodies. Some patients underwent invasive cardiopulmonary exercise test, and all of those had evidence of neurovascular dysregulation and dysautonomia. The authors state patient symptoms were consistent with ME/CFS diagnosis.
Of 16 patients, 9 patients were treated with IVIG, The dose was 2g/kg split over 3 days for the first infusion then 2g/kg split over 2 days every 3 weeks thereafter. Two-thirds of patients experienced resolution and one-third experienced improvement. None of the 7 untreated patients improved.
The authors cite a 2021 paper by Joseph et. al (also from Yale) hypothesizing neurovascular dysregulation from damaged small nerve fibers contributes to exercise intolerance, inadequate cardiac preload and impaired systemic oxygen extraction. Dysregulated microvascular tone of perivascular myocytes reduces venoconstriction, leading to impaired venous return and low cardiac preload. SFN results in inappropriate dilation of cutaneous arteriovenous shunts and shunting of oxygenated blood away from exercising muscles, resulting in impaired peripheral oxygen utilization.
The authors believe that IVIG treats postviral SFN multiple ways, including anti-inflammatory modulation of autoreactive B cells and dysimmunity, allowing damaged, unmyelinated small nerve fibers to regenerate. They call for a larger trial of IVIG in postinfectious SFN.
My comment:
The hypothesis is congruent with my personal experience. It almost seems like ME/CFS patients have the opposite problem with endothelial function compared to what is seen in heart disease/metabolic syndrome and diabetes, in that they have trouble dilating their blood vessels, while we have trouble constricting them.
A number of ME/CFS patients have reported worsening on IVIG. I would like to know if the authors saw initial worsening with subsequent improvement, or if the initial worsening was not experienced by this patient group. The dosage could also be a factor. Low doses of IVIG stimulate the immune system, whereas higher doses suppress it. Since IVIG is not an approved treatment for ME/CFS, there is no standardized dosing amount or schedule.
"Case-Control Study of Individuals With Small Fiber Neuropathy After COVID-19"
My summary:
Yale School of Medicine Department of Neurology found Small Fiber Neuropathy in Post-COVID-19 patients, most of them having had "mild" COVID19. Patients exhibited PEM, dysautonomia, and other ME/CFS symptoms. SFN was diagnosed by skin punch biopsy. Some, but not all patients were positive for sensory neuropathy autoantibodies. Some patients underwent invasive cardiopulmonary exercise test, and all of those had evidence of neurovascular dysregulation and dysautonomia. The authors state patient symptoms were consistent with ME/CFS diagnosis.
Of 16 patients, 9 patients were treated with IVIG, The dose was 2g/kg split over 3 days for the first infusion then 2g/kg split over 2 days every 3 weeks thereafter. Two-thirds of patients experienced resolution and one-third experienced improvement. None of the 7 untreated patients improved.
The authors cite a 2021 paper by Joseph et. al (also from Yale) hypothesizing neurovascular dysregulation from damaged small nerve fibers contributes to exercise intolerance, inadequate cardiac preload and impaired systemic oxygen extraction. Dysregulated microvascular tone of perivascular myocytes reduces venoconstriction, leading to impaired venous return and low cardiac preload. SFN results in inappropriate dilation of cutaneous arteriovenous shunts and shunting of oxygenated blood away from exercising muscles, resulting in impaired peripheral oxygen utilization.
The authors believe that IVIG treats postviral SFN multiple ways, including anti-inflammatory modulation of autoreactive B cells and dysimmunity, allowing damaged, unmyelinated small nerve fibers to regenerate. They call for a larger trial of IVIG in postinfectious SFN.
My comment:
The hypothesis is congruent with my personal experience. It almost seems like ME/CFS patients have the opposite problem with endothelial function compared to what is seen in heart disease/metabolic syndrome and diabetes, in that they have trouble dilating their blood vessels, while we have trouble constricting them.
A number of ME/CFS patients have reported worsening on IVIG. I would like to know if the authors saw initial worsening with subsequent improvement, or if the initial worsening was not experienced by this patient group. The dosage could also be a factor. Low doses of IVIG stimulate the immune system, whereas higher doses suppress it. Since IVIG is not an approved treatment for ME/CFS, there is no standardized dosing amount or schedule.
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