SEARCHCASE_REPORTneurology, immunology

case_report·neurology, immunology, clinical trial, observational study·PMC10766082

Characterizing Acute-Onset Small Fiber Neuropathy

Neurology® Neuroimmunology & Neuroinflammation · 7 authors, 1 centre

AI SUMMARY

FIDELITY 100%

POPULATION20 consecutive patients with probable or definite acute-onset small fiber neuropathy diagnosed using NEURODIAB criteria at a tertiary neuromuscular center

INTERVENTION

COMPARISONSerum reactivity from 10 healthy subjects and 12 diseased controls compared with patient sera in in vitro immunohistochemical assays

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TL;DR

This retrospective case series of 20 patients from a tertiary center described acute-onset small fiber neuropathy (AOSFN) as typically presenting with acute, non-length-dependent, symmetric painful neuropathy frequently triggered by infection or vaccination. In vitro studies demonstrated IgG immunoreactivity against nerve tissue in 70% of patients but not in controls, suggesting an immune-mediated origin.

Full summary

1,437 CHARS

This retrospective case series collected 20 consecutive patients with AOSFN over 5 years at a tertiary neuromuscular center. Diagnosis was based on NEURODIAB criteria with a 28-day threshold for acute onset. Clinical, neurophysiologic, neuropathologic, and experimental investigations were performed. Patients presented predominantly with acute, non-length-dependent, symmetric painful neuropathy, most frequently in middle-aged women, often preceded by infection or vaccination. Abnormal diagnostic findings included laser-evoked potentials (60%), epidermal nerve fiber density reduction (55%), warm detection thresholds (39%), and electrochemical skin conductance (31%). In vitro studies demonstrated IgG immunostaining against nerve tissue in 70% of patients, with sera binding to unmyelinated fibers, Schwann cells, paranodes, and dorsal root ganglia, but not in healthy or diseased controls. The disease course was variable, with partial or complete recovery in 65% of patients and relapsing or chronic courses in the remainder. Corticosteroids were beneficial in the acute phase in three patients, while IVIg was ineffective in two patients treated long after onset. Limitations include the small sample size, potential referral bias favoring more severe cases, sera collected months after onset potentially missing transient immune processes, and the inability to establish whether immunoreactions were causative or consequential.

PICO

PPOPULATION

20 consecutive patients with probable or definite acute-onset small fiber neuropathy diagnosed using NEURODIAB criteria at a tertiary neuromuscular center

OOUTCOME

Clinical characteristics, neurophysiologic test results (LEPs, WDT, ESC, ENF density), disease course, autoantibody profiles, and in vitro serum immunoreactivity against mouse nerve tissue

STUDY TYPE

case_report

SPECIALTY

neurology

SUMMARISED BY

AI pipeline

FIDELITY CHECK

100% · A

ORIGINAL PAPER

PMC10766082

Characterizing Acute-Onset Small Fiber Neuropathy

Neurology® Neuroimmunology & Neuroinflammation

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ABSTRACT

Background and Objectives Immune-mediated small fiber neuropathy (SFN) is increasingly recognized. Acute-onset SFN (AOSFN) remains poorly described. Herein, we report a series of AOSFN cases in which immune origins are debatable. Methods We included consecutive patients with probable or definite AOSFN. Diagnosis of SFN was based on the NEURODIAB criteria. Acute onset was considered when the maximum intensity and extension of both symptoms and signs were reached within 28 days. We performed the following investigations: clinical examination, neurophysiologic assessment encompassing a nerve conduction study to rule out large fiber neuropathy, laser-evoked potentials (LEPs), warm detection thresholds (WDTs), electrochemical skin conductance (ESC), epidermal nerve fiber density (ENF), and patient serum reactivity against mouse sciatic nerve teased fibers, mouse dorsal root ganglion (DRG) sections, and cultured DRG. The serum reactivity of healthy subjects (n = 10) and diseased controls (n = 12) was also analyzed. Data on baseline characteristics, biological investigations, and disease course were collected. Results Twenty patients presenting AOSFN were identified (60% women; median age: 44.2 years [interquartile range: 35.7–56.2]). SFN was definite in 18 patients (90%) and probable in 2 patients. A precipitating event was present in 16 patients (80%). The median duration of the progression phase was 14 days [5–28]. Pain was present in 17 patients (85%). Twelve patients (60%) reported autonomic involvement. The clinical pattern was predominantly non–length-dependent (85%). Diagnosis was confirmed by abnormal LEPs (60%), ENF (55%), WDT (39%), or ESC (31%). CSF analysis was normal in 5 of 5 patients. Antifibroblast growth factor 3 antibodies were positive in 4 of 18 patients (22%) and anticontactin-associated protein-2 antibodies in one patient. In vitro studies showed IgG immunoreactivity against nerve tissue in 14 patients (70%), but not in healthy subjects or diseased controls. Patient serum antibodies bound to unmyelinated fibers, Schwann cells, juxtaparanodes, paranodes, or DRG. Patients' condition improved after a short course of oral corticosteroids (3/3). Thirteen patients (65%) showed partial or complete recovery. Others displayed relapses or a chronic course. Discussion AOSFN primarily presents as an acute, non–length-dependent, symmetric painful neuropathy with a variable disease course. An immune-mediated origin has been suggested based on in vitro immunohistochemical studies.

CITATION EXPORT

Thierry Gendre, Jean-Pascal Lefaucheur, Tarik Nordine et al.. Characterizing Acute-Onset Small Fiber Neuropathy. Neurology® Neuroimmunology & Neuroinflammation. (2024). https://doi.org/10.1212/NXI.0000000000200195

AUTHORS

7 · 1 CENTRES

Thierry Gendre, Jean-Pascal Lefaucheur, Tarik Nordine, Yasmine Baba-Amer, François-Jérôme Authier, Jérôme Devaux, Alain Créange

From the Service de Neurologie (T.G., A.C.), CHU Henri Mondor APHP; Centre de Référence des Maladies Neuromusculaires Nord/Est/Ile-de-France (T.G., J.-P.L., T.N., F.-J.A., A.C.); Unité de Neurophysiologie Clinique (J.-P.L., T.N.), CHU Henri Mondor APHP; Unité de Recherche EA 4391 (J.-P.L., T.N., A.C.), Faculté de Santé, UniversitéParis Est Créteil; IMRB INSERM U955-Equipe 10 (Y.B.-A., F.-J.A.), UniversitéParis Est Créteil; Service d’Anatomo-Pathologie (F.-J.A.), CHU Henri Mondor APHP, Créteil; and Institut de Génomique Fonctionnelle (J.D.), Universitéde Montpellier, CNRS, INSERM, France.