Assessment of the Prevalence of Small Fiber Peripheral Neuropathy Among Non-diabetic Obese Patients

Background / rational:

Obesity is associated with significant comorbidities including type 2 diabetes (insulin resistance), heart disease, stroke, hypertension, sleep apnea syndrome, dyslipidemia, cancer, hepatobiliary diseases, orthopedic complications and psychosocial impact 1 .

Peripheral neuropathy is a known complication in the type I and II diabetes and glucose intolerance and metabolic syndrome in 2. Outside of diabetes (type I and II) that are associated with cardiovascular risk high vascular, presence of metabolic syndrome constitutes in itself a well demonstrated vascular risk factor. Its definition requires the presence of three elements from the following 5: abdominal obesity (high waist circumference), high blood pressure, high fasting blood sugar, high triglycerides and / low HDL-cholesterol 3.

This peripheral neuropathy predominantly affects sensory fibers of small poorly myelinated diameter (Aδ fibers and C) and autonomous sensory fibers and is called small fiber neuropathy 4. The cardinal sign of NAION is the presence of neuropathic pain but abnormalities in physical examination are often absent and conventional electromyography is faulted to make the diagnosis. These small fibers are also constituent of the autonomic nervous system and causes damage autonomic dysfunction that can manifest the cardiovascular system (hypotension, cardiac conduction disorders), digestive, sweat, sphincter. neuropathy of the diagnosis of small fibers is suggested clinically by the presence of neuropathic pain often contrasting with a normal clinical examination. The confirmation is based on electrophysiology with various techniques and quantification of intra-epidermal nerve fibers.

Main objective / secondary:

Primary objective :

To determine the prevalence of a small fiber peripheral neuropathy in nondiabetic obese patients, by measuring skin conductance ion Chlorine (Sudoscan®) evaluating small fibers C autonomic

Secondary objectives:

• Evaluation of the prevalence of occurrence of peripheral neuropathy by Sudoscan® during follow-up after treatment of obese patients with bariatric surgery (months) M1, 3, 6, 9, 12.
• Correlation of results obtained Sudoscan® quantitative sensory testing (QST) Thermotest® evaluating small sensory fibers Aδ, among non-operated non-diabetic obese patients and in the postoperative follow-up (months) M1, 3, 6, 9, 12.
• Characterization of electromyographic parameters (motor and sensory conduction) in patients with a skin conductance measured by lowered Sudoscan® and / or a threshold of sensitivity to pain increased Thermotest®.
• Correlation between the presence of a small fiber neuropathy in non-diabetic obese subjects with clinical and biological parameters collected.

Methodology Design: prospective, single-center Study duration: 24 months (estimate: 3-5 patients included / week of 15 patients collected in central obesity / week) including 12 months of inclusion.

Number of topics to include: 100 over a period of one year to adjust to the rhythm of the inclusions.

As mentioned, patients will be a measure of impedance of the skin to products chlorine ions by the sweat glands via the Sudoscan®, marketed and used among diabetic patients or not for the detection of violations neuropathic (cf. references and CE certificate attached to the dossier).

The Thermotest® is also marketed and used in diabetic and non-diabetic patients (see references and CE certificate attached to the dossier).

Our center has gained experience of these techniques for the detection of peripheral neuropathy in several patient populations (diabetes and cancer in particular); manipulators (doctors and technicians) are trained in these techniques.