Different distributions of nerve demyelination in chronic acquired multifocal polyneuropathies

• Published in: Chinese Medical Journal
• Main Authors: Xia-Jun Zhou, Ying Zhu, De-Sheng Zhu, Lu Han, Qian-Yun Liu, Xiao-Niu Liang, Yong Hao, Ze-Zhi Li, Yang-Tai Guan, Yan-Jie Yin, Xiu-Yuan Hao
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wolters Kluwer 2020
• Subjects: Medicine; R; Sumner; DML
• Online Access: https://doi.org/10.1097/CM9.0000000000001073; https://doaj.org/article/c2253f6a6f5d409e8eca49a6da1b1e9b

Abstract. Background. Multifocal motor neuropathy (MMN), Lewis-Sumner syndrome (LSS), and many chronic inflammatory demyelinating polyradiculoneuropathies (CIDPs) are representative of acquired multifocal polyneuropathy and are characterized by conduction block (CB). This retrospective study aimed to investigate the demyelinating distribution and the selective vulnerability of MMN, LSS, and CIDP with CB (CIDP-CB) in nerves. Methods. Fifteen LSS subjects (107 nerves), 24 MMN subjects (176 nerves), and 17 CIDP-CB subjects (110 nerves) were included. Their clinical information was recorded, blood and cerebrospinal fluid tests were conducted, and nerve conductions of the median, ulnar, radial, peroneal, and tibial nerves were evaluated. CB, temporal dispersion, distal motor latency (DML), and F-wave latency were recorded, and nerve conduction velocity, terminal latency index, and modified F-wave ratio were calculated. Results. CB was more likely to occur around the elbow in CIDP-CB than in MMN (78.6% vs. 6.8%, P < 0.01) but less likely to occur between the wrist and the elbow than in LSS (10.7% vs. 39.3%, P < 0.05). Tibial nerve CB was most frequently observed in MMN (47.4%, P < 0.05). CIDP-CB was characterized by a prolonged DML in all nerves, and slow motor nerve velocity of the upper limb was significant when CB nerves were excluded (P < 0.05). Conclusions. We report the different distributions of segmental and diffuse demyelination of the ulnar and tibial nerves in LSS, MMN, and CIDP-CB. These distinct distributions could help in differentiating among these conditions.