Nerve ultrasound characteristics of immunoglobulin M neuropathy associated with anti-myelin-associated glycoprotein antibodies.
Muscle Nerve 2022;
65:667-675. [PMID:
35353922 DOI:
10.1002/mus.27542]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 03/21/2022] [Accepted: 03/22/2022] [Indexed: 11/06/2022]
Abstract
INTRODUCTION/AIMS
Immunoglobulin M neuropathy associated with anti-myelin-associated glycoprotein antibody (IgM/anti-MAG) neuropathy typically presents with chronic, distal-dominant symmetrical sensory or sensorimotor deficits. Ultrasonographic studies of IgM/anti-MAG neuropathy are limited, and were all performed on Western populations. We aimed to characterize the nerve ultrasonographic features of IgM/anti-MAG neuropathy in the Japanese population and evaluate whether they differ from the findings of the common subtypes of chronic inflammatory demyelinating polyneuropathy (CIDP).
METHODS
In this cross-sectional study, we retrospectively reviewed medical records and extracted the cross-sectional areas (CSAs) of C5-C7 cervical nerve roots and median and ulnar nerves of 6 IgM/anti-MAG neuropathy patients, 10 typical CIDP (t-CIDP) patients, 5 multifocal CIDP (m-CIDP) patients, and 17 healthy controls (HCs).
RESULTS
Cervical nerve root CSAs were significantly larger at every examined site on both sides in IgM/anti-MAG neuropathy than in m-CIDP and HCs but were comparable to those in t-CIDP. Peripheral nerve enlargements were greatest at common entrapment sites (ie, wrist and elbow) in IgM/anti-MAG neuropathy, a pattern shared with t-CIDP but not with m-CIDP. The degree of nerve enlargement at entrapment sites compared to non-entrapment sites was significantly higher in IgM/anti-MAG neuropathy than in t-CIDP.
DISCUSSION
Our study delineated the ultrasonographic features of IgM/anti-MAG neuropathy in the Japanese population and observed similar characteristics to those of t-CIDP, with subtle differences. Further studies comparing results from various populations are required to optimize the use of nerve ultrasound worldwide.
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