Department of Physiology and Pathophysiology, University of Erlangen, Universitätsstr. 17, 91054, Erlangen, Germany.
Muscle Nerve. 2013 Mar;47(3):357-63. doi: 10.1002/mus.23543. Epub 2012 Nov 24.
Objective diagnosis of small fiber impairment is difficult.
We used the quantitative sudomotor axon reflex test (QSART) and axon-reflex-flare-test in the foot and thigh of 46 patients with peripheral neuropathy to assess C-fiber function in addition to conventional neurography and thermal threshold testing.
In all patients, small fiber impairment was suspected because of abnormal warmth detection thresholds (76% of all tested) and/or pain in the feet. A total of 83% had reduced axon-reflex flare areas and 17% lower QSART scores. Patients with pure small fiber neuropathy had higher rates of reduced flare areas (87.5%) and sweating rates (25.5%). There was no difference between patients with and without pain regarding thermotesting and axon-reflex testing.
Both axon-reflex tests are helpful to identify objectively patients with small fiber impairment. Afferent and efferent C-fiber classes can be impaired differently. These tests detect small fiber impairment, but they cannot differentiate between painful and nonpainful neuropathy.
小纤维损害的客观诊断较为困难。
我们对 46 例周围神经病变患者的足部和大腿进行了定量性自主神经反射试验(QSART)和轴突反射性红斑试验,除了常规神经电图和温度阈值测试外,还评估了 C 纤维功能。
所有患者均因异常温热感觉阈值(所有测试的 76%)和/或足部疼痛而怀疑存在小纤维损害。轴突反射性红斑面积减少和 QSART 评分降低的患者分别占 83%和 17%。纯小纤维性神经病患者的红斑面积减少(87.5%)和出汗率(25.5%)更高。在热测试和轴突反射测试方面,有疼痛和无疼痛的患者之间没有差异。
这两种轴突反射试验都有助于客观地识别小纤维损害的患者。传入和传出 C 纤维类可以不同程度地受损。这些测试可以检测小纤维损害,但不能区分疼痛性和非疼痛性神经病。