Rousseaux M, Cassim F, Bayle B, Laureau E
Service de Rééducation Neurologique, Hôpital Swynghedauw, Centre Hospitalier Universitaire, France.
Stroke. 1999 Oct;30(10):2223-9. doi: 10.1161/01.str.30.10.2223.
The aim of the study was to assess the consequences of severe spinothalamic tract lesions resulting from lateral medullary infarct and to show that a specific pain perception can be elicited by strong thermal stimulation.
Both patients examined presented with severe thermoalgic dissociation of the limbs contralateral to the lesion, with normal discriminative somatosensory perception and motor strength. They reported pain perception when touching very warm (>50 degrees C to 60 degrees C) objects and a brisk, occasionally uncontrolled withdrawal reaction of the arm and hand under the same conditions, without any perception of the heat nature of the stimulus. Warm stimulation, <45 degrees C, elicited no thermal perception or discrimination. Pain perception could be elicited in both patients by increasing the temperature, with a reproducible threshold of 47 degrees C to 49 degrees C. Pain always occurred after a prolonged delay of 8 to 10 seconds in response to threshold heat, and was described as deep and osseous, and clearly different from that perceived on the nonaffected side. The delay was much shorter when the temperature was increased by 4 degrees C to 5 degrees C. Cold stimulation elicited similar pain perception in one patient. Analysis of subjective perception of laser stimulation showed a much higher pain threshold on the affected hand. There were no laser-evoked potentials on this side, which suggested major spinothalamic injury. Assessment of the RIII noxious reflex revealed persistent response withdrawal reactions, with an increased threshold on the affected side, and partial consciousness of the noxious nature of the stimulus.
To our knowledge, this is the first description of the appearance of pain perception of high temperatures in patients with severe spinothalamic injury who are suffering from a complete loss of temperature perception. This implies that noxious thermal stimulation can still be perceived via extra spinothalamic pathways (which are slow and multisynaptic), such as the spinoreticulothalamic tract. Patients with Wallenberg syndrome should be informed and made aware of their residual perception of and reactions to noxious stimulation.
本研究旨在评估外侧延髓梗死导致的严重脊髓丘脑束损伤的后果，并证明强烈的热刺激可引发特定的疼痛感知。
两名接受检查的患者均表现出病变对侧肢体严重的温度性疼痛分离，具有正常的辨别性躯体感觉和运动力量。他们报告在触摸非常热（>50摄氏度至60摄氏度）的物体时会有疼痛感知，并且在相同条件下手臂和手部会出现快速、偶尔不受控制的退缩反应，但对刺激的热性质没有任何感知。低于45摄氏度的温热刺激不会引发热感知或辨别。通过升高温度，两名患者均可引发疼痛感知，可重复的阈值为47摄氏度至49摄氏度。对阈值热刺激的反应，疼痛总是在8至10秒的长时间延迟后出现，且被描述为深部和骨性疼痛，明显不同于未受影响侧所感知到的疼痛。当温度升高4摄氏度至5摄氏度时，延迟要短得多。冷刺激在一名患者中引发了类似的疼痛感知。对激光刺激主观感知的分析显示，患侧手部的疼痛阈值要高得多。该侧没有激光诱发电位，这表明脊髓丘脑束受到严重损伤。对RIII有害反射的评估显示存在持续的反应性退缩反应，患侧阈值升高，且对刺激的有害性质有部分意识。
据我们所知，这是首次描述患有严重脊髓丘脑损伤且完全丧失温度感知的患者出现高温疼痛感知的情况。这意味着有害的热刺激仍可通过脊髓丘脑外通路（缓慢且多突触），如脊髓网状丘脑束被感知。应告知患有瓦伦贝格综合征的患者，并使其意识到他们对有害刺激的残留感知和反应。
