Data for: Sudden paraparesia in an old man

The first consideration with this presentation pattern is a spinal cord lesion, most likely anterior cord syndrome characterized by loss of motor function, pain, pinprick, and light touch below the level of the lesion .
In general, pathologic processes involving the spinal cord may be divided into processes affecting the cord or its blood supply primarily and processes that compress the cord, most often originating outside the dura.The main causes of anterior cord syndrome are external compression (such as mass, discopathy, trauma) , ischemia (such as aortic surgery or involvement, aortic angiography, laceration or thrombosis of the anterior spinal artery or a major feeding vessel, severe hypotension, myocardial infarction , vasospasm),Inflammation, infection and demyelination. Note that lesions from ischemia usually are incomplete. If the physical examination does not support a cord syndrome or cauda equina syndrome (absence of UMN signs or a clear thoracic pinprick level, loss of perianal sensation and rectal tone, and urinary retention), the patient may have a peripheral neuropathy affecting the longest nerve tracts first (such as Guillain-Barré syndrome).

针对此种临床表现模式，首要考虑的诊断为脊髓病变，极大概率为脊髓前综合征（anterior cord syndrome），其特征为病变平面以下运动功能、痛觉、针刺觉及轻触觉丧失。
总体而言，累及脊髓的病理过程可分为两类：一类主要累及脊髓或其血供，另一类则压迫脊髓，后者通常起源于硬脊膜（dura）外。脊髓前综合征的主要病因包括外源性压迫（如占位性病变、椎间盘病变、创伤）、缺血性因素（如主动脉手术或受累、主动脉造影、脊髓前动脉（anterior spinal artery）或主要供血血管撕裂或血栓形成、严重低血压、心肌梗死、血管痉挛），以及炎症、感染与脱髓鞘病变。需注意，缺血所致的病变通常为不完全性损伤。若体格检查结果不支持脊髓综合征或马尾综合征（cauda equina syndrome）（无上运动神经元（upper motor neuron, UMN）体征、无明确的胸段针刺觉平面、肛周感觉及直肠张力丧失、尿潴留），则患者可能罹患以最长神经束最先受累为特征的周围神经病，例如吉兰-巴雷综合征（Guillain-Barré syndrome）。