Sasaki Hideyuki, Kawamura Nobutoshi, Dyck Peter J, Dyck P James B, Kihara Mikihiro, Low Phillip A
1Wakayama Medical University, Wakayama, Japan.
2Kawamura Hospital, Gifu, Japan.
Diabetol Int. 2020 Jan 8;11(2):87-96. doi: 10.1007/s13340-019-00424-7. eCollection 2020 Apr.
The diabetic state results in neuropathy. The main causative mechanism is hyperglycemia, although microvascular involvement, hypertriglyceridemia, as well as genetic and immune mechanisms may be contributory. There is a growing spectrum of types of diabetic neuropathies that differ based on the type of fibers involved (e.g. myelinated, unmyelinated, autonomic, somatic), distribution of nerves involved, and mechanisms of neuropathy. The most common type is distal sensory neuropathy (DSN), which affects the distal ends of large myelinated fibers, more often sensory than motor, and is often asymptomatic. The next-most common is distal small fiber neuropathy (DSFN), which largely affects the unmyelinated fibers and carries the phenotype of burning feet syndrome. Diabetic autonomic neuropathy (DAN) occurs when widespread involvement of autonomic unmyelinated fibers occurs, and patients can be incapacitated with orthostatic hypotension as well as neurogenic bladder and bowel involvement. Radiculoplexus diabetic neuropathy causes proximal weakness and pain, usually in the lower extremity, and has a combination of immune, inflammatory, and vascular mechanisms. The nerve roots and plexus are involved. These patients present with proximal weakness of a subacute onset, often with severe pain and some autonomic failure. Finally, rapid and sustained reduction of blood glucose can result in treatment-induced diabetic neuropathy (TIND), which largely affects the sensory and autonomic fibers. This occurs if HbA1c is rapidly reduced within 3 months, and the likelihood is proportional to the original A1c and the size of the reduction.
糖尿病状态会导致神经病变。主要致病机制是高血糖，不过微血管病变、高甘油三酯血症以及遗传和免疫机制也可能起作用。糖尿病神经病变的类型越来越多，根据受累纤维类型（如有髓纤维、无髓纤维、自主神经纤维、躯体神经纤维）、受累神经分布以及神经病变机制而有所不同。最常见的类型是远端感觉神经病变（DSN），它影响大的有髓纤维的远端，感觉功能受累比运动功能更常见，且通常无症状。第二常见的是远端小纤维神经病变（DSFN），它主要影响无髓纤维，并表现为灼足综合征的症状。糖尿病自主神经病变（DAN）发生于自主神经无髓纤维广泛受累时，患者可能会因直立性低血压以及神经源性膀胱和肠道受累而丧失活动能力。神经根丛性糖尿病神经病变导致近端肌无力和疼痛，通常发生在下肢，其发病机制涉及免疫、炎症和血管因素，神经根和神经丛均受累。这些患者表现为亚急性起病的近端肌无力，常伴有严重疼痛和一些自主神经功能障碍。最后，血糖的快速持续降低可导致治疗性糖尿病神经病变（TIND），它主要影响感觉神经纤维和自主神经纤维。如果糖化血红蛋白（HbA1c）在3个月内迅速降低，就会发生这种情况，其发生可能性与初始糖化血红蛋白水平及降低幅度成正比。
