Causes Associated With Small Fiber Neuropathy (SFN).

Study Overview
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Brief Summary
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Small fiber neuropathy (SFN) is an injury of cutaneous nerve fibers, mainly by a decrease in their density within the cutaneous tissue. The symptomatology associated with this SFN is broad with symptoms that are essentially sensory, but also autonomic. The etiologies of SFN are numerous (diabetes, drug, infectious, immunological...) and clinically non-specific, justifying a broad etiological assessment. The appearance of staged skin biopsies in the SFN balance sheet has greatly helped to improve diagnosis. Despite this, a significant part of SFN remains without associated etiology and is considered idiopathic. As the distribution of the different causes of SFN remains a missing data to date, the completion of this cohort study by one of the SFN reference centres should make it possible to establish the prevalence of SFN causes over a large population. Only patients with clinical symptoms that may be related to SFN and who have been sampled for SFN, positive or not, will be eligible for recruitment. The result of the anatomopathological sampling will allow patients to be separated into two groups, with or without SFN. The main judgement criteria will be the prevalence of etiologies associated with SFN: diabetes, medication, systemic lupus erythematosus, Gougerot-Sjögren syndrome, amylosis, dysthyroidism, alcoholism, vitamin B12 deficiency, HIV infection, hepatitis C, paraneoplastic syndrome, hereditary disease (Fabry disease, Friedreich ataxia,...), idiopathic, others.

Official Title
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Retrospective Study of Causes Associated With Small Fiber Neuropathies.

Conditions
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Small Fiber Neuropathy

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age of majority (>18 years old) Clinically managed patient at Brest University Hospital Patient who had a skin biopsy with anatomopathological examination for SFN performed at the University Hospital of Brest Exclusion Criteria: Under age of majority (<18 years old) Patient not followed at Brest University Hospital Refusal to participate to the study

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Prevalence of etiologies associated with SFN | Source population will be patients with symptoms that may be related to SFN, who have performed a biopsy for SFN. Patient will be considered to have SFN if he or she has a decrease in intra-epidermal distal density at nerve endings below the 5th percentile and at least one clinical sign in favour of small fibre neuropathy. Clinical signs in favour of SFN are as follows : Sensitive symptoms: burns, stings, numbness, tingling, hot/cold sensations, electric shocks, hyperesthesia, allodynia, intolerance of bed sheets, pruritus, restless legs. Vegetative symptoms: erectile disorders, dry syndrome, sweating, hot flashes, vertigo/discomfort (orthostatic hypotension), digestive and/or urinary disorders, resting tachycardia, palpitations Vascular symptoms: erythromelalgia, acrosyndrome | 1 year |