A reappraisal of the presence of small or large fiber neuropathy in patients with erythromelalgia - 20/04/21

Doi : 10.1016/j.neucli.2021.03.008

Pauline Reach ^a,^b,^{^{1
The authors contributed equally to this work as co-first authors.},}⁎ , Isabelle Lazareth ^c,^{^{1
The authors contributed equally to this work as co-first authors.}}, François Coudore ^d,^e, Audrey Stansal ^c, Raphaël Attal ^c, Ulrique Michon-Pasturel ^c, Parinaz Ghaffari ^c, Alexandra Yannoutsos ^c, Hélène Beaussier ^f, Emmanuelle Sacco ^f, Maxime Wang ^f, Pascal Priollet ^c, Jean-Pascal Lefaucheur ^g,^h,^{^{2
co-senior authors.}}, Mathieu Zuber ^a,^b,^{^{2
co-senior authors.}}
^a Neurological and Neurovascular Department, Saint Joseph Hospital, Paris, France
^b Faculty of Medicine, Paris University, France
^c Vascular Medicine Department, Saint Joseph Hospital, Paris, France
^d Clinical Microbiological Department, Saint Joseph Hospital, Paris, France
^e Neuropharmacology Laboratory, Inserm CESP, Team MOODS, Faculty of Pharmacy, Paris-Saclay University, France
^f Clinical Research Center, Saint Joseph Hospital, Paris, France
^g EA 4391, Faculty of Medicine, Paris Est Créteil University, Créteil, France
^h Clinical Neurophysiology Unit, Department of Physiology, Henri Mondor Hospital, Assistance Publique - Hôpitaux de Paris, Créteil, France

^⁎Corresponding author at: Neurological and Neurovascular Department, Saint Joseph Hospital, Paris, France.Neurological and Neurovascular DepartmentSaint Joseph HospitalParisFrance

Sous presse. Épreuves corrigées par l'auteur. Disponible en ligne depuis le Tuesday 20 April 2021
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Abstract

Objective

To assess the contribution of large and small nerve fiber alteration in erythromelalgia (EM).

Methods

Thirty-three EM patients were included and underwent clinical evaluation based on EM severity score, DN4, and Utah Early Neuropathy Scale (UENS) score. Neurophysiological evaluation consisted in nerve conduction studies (NCS) for large nerve fibers and specific tests for small nerve fibers: electrochemical skin conductance, cold and warm detection thresholds, and laser evoked potentials. Finally, the evaluation of vascular changes was based on the presence of clinical feature of microvascular disorders and the measurement of the Toe Pressure Index (TPI).

Results

While 28 patients (85%) had vascular alteration on TPI or clinical features, 23 patients (70%) had small-fiber neuropathy on neurophysiological tests, and only 10 patients (30%) had large fiber neuropathy on NCS. Regarding clinical scores, there was no difference between groups (presence or absence of large- or small-fiber neuropathy or microvascular disorder) except for a higher UENS score in patients with large fiber neuropathy.

Conclusion

Peripheral neuropathy, mostly involving small nerve fibers, is almost as common as microvascular changes in EM, but remains inconstant and not related to a specific neuropathic pattern or higher clinical severity.

Significance

The association of neuropathic and vascular factors is not systematic in EM, this syndrome being characterized by different pathophysiological mechanisms leading to a common clinical phenotype.

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Keywords : Erythermalgia, Erythromelalgia, Nd:YAP laser, Peripheral nervous system, Small-fiber neuropathy, Sudomotor function, Sudoscan, Thermotest