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

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

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).

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.

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