Evaluation of the Diagnostic Contributions of Nerve Ultrasound in Chronic Inflammatory Demyelinating Polyneuropathy Associating Systemic Diseases (CIDP Echo-nerf)

Study Overview
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Brief Summary
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Chronic inflammatory demyelinating polyradiculoneuritis (CIDP) is an autoimmune disorder of the peripheral nervous system, most commonly affecting the myelin sheath. The pathophysiology of CIDP is not completely understood, but both humoral and cellular immunity appear to be involved in the genesis of this disease. Some diseases are particularly associated with CIDP such as diabetes, monoclonal gammopathies and hematological diseases. CIDP can occur before, after or simultaneously with the onset of systemic diseases. The systemic diseases most often seen in association with polyneuropathies are lupus, Gougerot-Sjögren's syndrome and sarcoidosis. Ultrasound of peripheral nerves is a useful and accessible tool. In CIDP, this examination can reveal diffuse or segmental nerve hypertrophy. In addition to the size of the nerve, this exploration analyzes the echogenicity and the aspect of the different fascicles within the nerve. S. Goedee et al have shown that nerve ultrasound has very good diagnostic parameters and low interobserver variability in the diagnosis of CIDP. F. Härtig et al suggests that nerve ultrasound can predict the therapeutic response and describes 3 main patterns: hypoechoic enlargement (active inflammation), nerve enlargement with hyperechoic add-on fascicles (axonal degeneration) and almost no enlargement (cured CIDP).

Detailed Description
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CIDP may be progressive or relapsing, most frequently clinically symmetric, sensorimotor with proximal and distal involvement developing over at least 8 weeks but variants as distal, multifocal, focal, motor or sensory CIDP have been also described. Cell-mediated and humoral mechanisms act together in an aberrant immune response to cause damage to peripheral nerves but, by molecular mimicry it causes other autoimmune system diseases. This paper focuses on the intersection of CIDP and other autoimmune disease with an emphasis on shared pathology and mutually characteristics.

Official Title
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Evaluation of the Diagnostic Contributions of Nerve Ultrasound in Chronic Inflammatory Demyelinating Polyneuropathy Associating Systemic Diseases

Conditions
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Chronic Inflammatory Demyelinating Polyradiculoneuropathy

Intervention / Treatment
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* Other: None, pure observationnal study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients followed at Nîmes University Hospital between 2012 and 2021 Age > 18 years Diagnosis of definite CIDP or possible CIDP according to the new EFNS/PNS 2021 criteria Diagnosis of definite CIDP/CIDP possible with systemic diseases and respectively diagnosis of definite CIDP/CIDP possible for the control group confirmed by electroneuromyography, concordant with the clinical examination

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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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| CIDP associated with systemic diseases<br>Patients with CIDP associated with systemic diseases | Other: None, pure observationnal study<br>* pure observationnal study<br>|
| CIDP without systemic diseases<br>Patients with CIDP without other systemic diseases | Other: None, pure observationnal study<br>* pure observationnal study<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Median nerve cross-sectional area | Comparison of median nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| ulnar nerve at wrist cross-sectional area | Comparison of ulnar nerve at wrist cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| ulnar at mid-arm nerve cross-sectional area | Comparison of ulnar nerve at mid-arm cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| ulnar nerve at elbow cross-sectional area | Comparison of ulnar nerve at elbow cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| radial nerve cross-sectional area | Comparison of radial nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Day of diagnosis of CIDP | 
| superficial radial branch nerve cross-sectional area | Comparison of superficial radial branch nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| vagus nerve cross-sectional area | Comparison of vagus nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| C6 root nerve cross-sectional area | Comparison of C6 root nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| C5 root nerve cross-sectional area | Comparison of C5 root nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| sural nerve cross-sectional area | Comparison of sural nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| superficial fibula nerve cross-sectional area | Comparison of superficial fibula nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| tibial nerve at ankle cross-sectional area | Comparison of tibial nerve at ankle cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| popliteal nerve cross-sectional area | Comparison of popliteal nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| fibular nerve at neck cross-sectional area | Comparison of fibular nerve at neck cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 | 
| fibular at supra-neck nerve cross-sectional area | Comparison of fibular at supra-neck nerve cross-sectional area on nerve ultrasound in patients with definite PIDC/PIDC with associated systemic disease with that of patients with PIDC/PIDC without systemic disease | Base line, Day 0 |