Focused Neuromuscular Ultrasound Approach for the Diagnosis of Chronic Inflammatory Demyelinating Polyneuropathy

May 2023

Abstract

Purpose:

Previous ultrasonographic studies of individuals with chronic inflammatory demyelinating polyneuropathy (CIDP) have shown nerve enlargement at several sites. This prospective study compares only the bilateral median and ulnar nerves of individuals with CIDP with reference values to determine the clinical usefulness of this focused approach as a diagnostic tool.

Methods:

The cross-sectional area, echogenicity, and vascularity of the bilateral median and ulnar nerves of 25 subjects with CIDP were measured using ultrasound. Nineteen had typical CIDP based on the European Federation of Neurological Societies and the Peripheral Nerve Society guidelines, whereas six had atypical CIDP and were diagnosed based on clinical impression.

Results:

Focal nerve enlargement was found in at least one segment in all subjects. Subjects with typical CIDP had larger cross-sectional areas compared with subjects with atypical CIDP.

Conclusion:

A focused ultrasound study, involving only the median and ulnar nerves, is sensitive for the detection of nerve enlargement in CIDP. Measuring the cross-sectional area of the median and ulnar nerves is clinically feasible and may help establish the diagnosis of CIDP.

What is CIDP?

Chronic inflammatory demyelinating polyneuropathy (CIDP) can be thought of as the chronic form of AIDP. It is primarily distinguished both by its time course—by definition, symptoms must persist for at least 8weeks—and its responsiveness to corticosteroid treatment (AIDP, you may recall, is not steroid responsive). It tends to be monophasic, with a relatively gradual onset and even more gradual recovery, but some patients can present with a relapsing and remitting course. Otherwise, CIDP closely resembles AIDP, with predominantly distal, symmetric, ascending motor weakness and decreased or absent reflexes. Albuminocytologic dissociation in the CSF is a hallmark finding, as with AIDP. IVIG, PLEX, or pulse high- dose corticosteroids are first- line treatment.

There are several CIDP variants, including sensory- predominant and pure motor forms, that can be harder to recognize and diagnose. CSF analysis and electrophysiologic testing are helpful.