Focal chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is defined as involving the brachial or lumbosacral plexus, or one or more peripheral nerves in one upper or one lower limb (monomelic distribution). However, other auto-immune neuropathies such as Lewis-Sumner syndrome (LSS) and multifocal motor neuropathy (MMN) can also have a focal onset. From a retrospective cohort of 30 focal CIDP patients with a monomelic onset dating back at least 2 years, we distinguished patients with plexus involvement (focal demyelinating plexus neuropathy [F-PN], n = 18) from those with sensory or sensorimotor (F-SMN, n = 7), or purely motor (F-MN, n = 5) impairment located in one or several peripheral nerves. Few (39%) F-PN patients had motor nerve conduction abnormalities, but the majority showed proximal conduction abnormalities in somatosensory evoked potentials (80%), and all had focal hypertrophy and/or increased short tau inversion recovery image signal intensity on plexus MRI. Impairment remained monomelic in most (94%) F-PN patients, whereas abnormalities developed in other limbs in 57% of F-SMN, and 40% of F-MN patients (P = .015). The prognosis of F-PN patients was significantly better: none had an ONLS score > 2 at the final follow-up visit, vs 43% of F-SMN patients and 40% of F-MN patients (P = .026). Our findings from a large cohort of focal CIDP patients confirm the existence of different entities that are typically categorized under this one term: on the one hand, patients with a focal plexus neuropathy and on the other, patients with monomelic sensori-motor or motor involvement of peripheral nerves. These two last subgroups appeared to be more likely to evolve to LSS or MMN phenotype, when F-PN patients have a more distinctive long-term, focal, benign course.

中文翻译：

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局灶性慢性炎症性脱髓鞘性多发性神经根神经病：发病、病程和明显特征

局灶性慢性炎症性脱髓鞘性多发性神经根神经病 (CIDP) 定义为累及臂丛或腰骶丛，或一只上肢或一只下肢的一根或多根周围神经（单体分布）。然而，其他自身免疫性神经病，如 Lewis-Sumner 综合征 (LSS) 和多灶性运动神经病 (MMN) 也可能有局灶性发作。我们对 30 名至少 2 年单体发病的局灶性 CIDP 患者进行回顾性队列研究，将神经丛受累（局灶性脱髓鞘性丛神经病变 [F-PN]，n = 18）患者与感觉或感觉运动（F- SMN，n = 7)，或位于一根或多根周围神经的纯运动 (F-MN，n = 5) 损伤。少数 (39%) F-PN 患者有运动神经传导异常，但大多数显示体感诱发电位近端传导异常（80%），并且在丛 MRI 上均有局灶性肥大和/或短 tau 反转恢复图像信号强度增加。大多数 (94%) F-PN 患者的损伤仍然是单体性的，而 57% 的 F-SMN 和 40% 的 F-MN 患者的其他肢体出现异常。P = .015）。F-PN 患者的预后明显更好：在最后一次随访中，没有一个 ONLS 评分 > 2，而 F-SMN 患者和 F-MN 患者分别为 43% 和 40% ( P = .026)。我们对一大群局灶性 CIDP 患者的研究结果证实了通常归类为这一术语的不同实体的存在：一方面，患有局灶性丛神经病变的患者，另一方面，患有单体感觉运动或运动受累的患者的周围神经。当 F-PN 患者具有更独特的长期、局灶性、良性病程时，这最后两个亚组似乎更有可能演变为 LSS 或 MMN 表型。