Clinical trial NCT06527183: Fibromyalgia and Small Fiber Neuropathy
Official title: Fibromyalgia and Small Fiber Neuropathy : Which Prevalence and Which Relationship With Pain ?
Study type: OBSERVATIONAL
Overall status: RECRUITING
Conditions: Chronic Pain Syndrome
Lead sponsor: Hospital Ambroise Paré Paris
Sponsor class: OTHER
First posted: 2024-07-30
Enrollment: 150
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: CASE_CONTROL
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients with fibromyalgia, other chronic pains (nociplastic or nociceptive) and healthy subjects

Brief summary: The primary objective of this study will be to assess the proportion of fibromyalgia patients with diffuse small-fiber neuropathy (i.e. in the upper and lower limbs) and compare this proportion to patients with other chronic pains (nociplastic, nociceptive) and with healthy controls. Our analysis will be based on the demonstration of structural abnormalities of small nerve fibers by means of skin biopsy, but also of functional abnormalities using four validated tests commonly used in this field: quantitative sensory testing (QST), laser evoked potential recordings, Sudoscan and confocal corneal microscopy. It will thus be possible to verify whether or not patients with small fiber neuropathy have a particular clinical profile in terms of pain, physical activity, comorbidities or pain impact.

Detailed description: Small fiber neuropathy has been observed in a large proportion of fibromyalgia patients. However, the pathophysiological role of these neurological abnormalities in determining the pain and other symptoms of fibromyalgia, and the specificity of these abnormalities, are not well understood.

The primary objective of this study will be to assess the proportion of fibromyalgia patients with diffuse small-fiber neuropathy (i.e. in the upper and lower limbs) and compare this proportion to patients with other chronic pains (nociplastic, nociceptive) and with healthy controls. Our analysis will be based on the demonstration of structural abnormalities of small nerve fibers by means of skin biopsy, but also of functional abnormalities using four validated tests commonly used in this field: quantitative sensory testing (QST), laser evoked potential recordings, Sudoscan and confocal corneal microscopy. It will thus be possible to verify whether or not patients with small fiber neuropathy have a particular clinical profile in terms of pain, physical activity, comorbidities or pain impact.

Eligibility criteria: Inclusion Criteria:

* patients over 18 years of age with no age limit -
* having given their signed consent to take part in the study
* affiliated to the French social security system
* able to be followed for the entire duration of the study
* reading and understanding French
* accepting the principle of the study and able to comply with its conditions
* suffering from chronic pain for at least six months of at least moderate intensity (≥ 4/10)
* fibromyalgia detected by the FiRST questionnare and defined by the revised diagnostic criteria of the WHO or chronic nociceptive or nociplastic pain without associated fibromyalgia.
* chronic pain for at least 6 months of at least moderate intensity (≥ 4/10)
* untreated or with stable analgesic treatment for at least 2 weeks prior to inclusion- normal neurological examination at inclusion

Exclusion Criteria:

* litigation or compensation-seeking
* cancer for less than 2 years
* known cause of small-fiber neuropathy such as diabetes, systemic disease, hypothyroidism, alcohol, renal failure, genetic disease
* clinical or EMG neuropathy
* peripheral or central nervous system pathology with or without associated neuropathic pain
* uncontrolled chronic pathology such as : morbid obesity, sleep apnea, uncontrolled hypertension, etc. - psychosis, previous suicide attempt
* drug or psychoactive substance abuse
* cognitive or psychological disorders incompatible with compliance with and/or understanding of the protocol
* participation in another biomedical research protocol.

Primary outcomes:
measure: Prevalence of small fiber neuropathy or pathology as assessed with skin punch biopsy in patients with fibromyalgia as compared to patients with other chronic pains and healthy subjects
timeFrame: Baseline and at 6 months
Secondary outcomes:
measure: Correlation between intraepidermal nerve fiber density and pain or other patient reported outcome measures (quality of life, distress, disability...)
timeFrame: Baseline and at 6 months
measure: Investigate the potential specificity of the results obtained by comparing them with pain patients without fibromyalgia or nerve damage (patients with any nociceptive or nociplastic pain without fibromyalgia) matched for age and gender
timeFrame: Baseline and at 6 months
measure: Monitor the evolution of abnormalities obtained over time (6 months) and correlate them with the evolution of pain and associated symptoms.
timeFrame: 6 months
measure: Determine the sensitivity and diagnostic value of corneal confocal microscopy and laser evoked potentials as compared with skin punch biopsy for exploring nociceptive fibers
timeFrame: Baseline and at 6 months
measure: Determine the diagnostic value of the sudoscan and quantified sensory tests compared with other tests for exploring nociceptive fibers in these patients
timeFrame: Baseline and at 6 months
Other outcomes:
Locations:
city: Boulogne-Billancourt
country: France
facility: Inserm U987
city: Paris
country: France
facility: Centre d'Evaluation et de Traitement de la douleur
Study officials:
affiliation: APHP
name: Nadine ATTAL, MD PhD
role: PRINCIPAL_INVESTIGATOR
References: