Hakusui S, Iwase S, Mano T, Takahashi A
Department of Neurology, Nagoya University School of Medicine.
Rinsho Shinkeigaku. 1990 Jun;30(6):668-71.
A 48-year-old man developed swelling, redness, and allodynia in his left palm. Routine physical and neurological examinations revealed no abnormal findings except for left palmar hyperhidrosis. A clinical diagnosis of minor reflex sympathetic dystrophy with causalgia was made. Skin sympathetic activity (SSA), dominating palm sweating and skin vasoconstriction, and discharges of single afferent fiber from the rapidly adapting-type I (RA-I) unit were recorded microneurography from the median nerve at the cubital fossa. SSA obtained from the affected side was significantly increased compared with that from the normal (right) side. The receptive field of RA-I unit in this case was larger than those of normal controls. Enlargement of the receptive field might suggest presence of collateral sprouting in the injured nerve fibers. Allodynia in the left palm was suspected to be resulted from misdirect sprouting between A alpha . beta to A delta . C fibers. Excessive sympathetic out flow to the skin is considered to be the cause of palmar hyperhidrosis, swelling with redness, and lowered pain threshold, since pain threshold is under regulation of SSA. It is concluded that these sensory and autonomic symptoms were resulted from increased sympathetic out flow to the skin and collateral sproutings in the peripheral nerve fibers.
一名48岁男性左手掌出现肿胀、发红及痛觉异常。常规体格检查和神经学检查未发现异常，仅左手掌多汗。临床诊断为伴有灼性神经痛的轻度反射性交感神经营养不良。通过微神经图记录肘窝正中神经的皮肤交感神经活动（SSA，主要支配手掌出汗和皮肤血管收缩）以及快速适应性I型（RA-I）单位的单根传入纤维放电。患侧获得的SSA与正常（右侧）相比显著增加。该病例中RA-I单位的感受野大于正常对照。感受野扩大可能提示受损神经纤维存在侧支发芽。左手掌的痛觉异常怀疑是由于Aα.β纤维与Aδ.C纤维之间的错误导向发芽所致。皮肤交感神经输出过多被认为是手掌多汗、肿胀发红和痛阈降低的原因，因为痛阈受SSA调节。结论是，这些感觉和自主神经症状是由于皮肤交感神经输出增加和外周神经纤维侧支发芽所致。
