可逆性后部脑病综合征是一种临床神经影像学综合征。临床特点包括头痛、意识障碍、癫癎发作及视觉障碍。影像学特征为大脑后部白质或（和）灰质病变。该病发生机制尚未完全明确，内皮损伤机制可能是关键因素。基础疾病是发病的重要因素，也是临床诊断的关键线索。大多数病例预后良好，临床和影像学异常可恢复。但严重病例如合并急性脑出血或大面积后颅窝水肿，导致梗阻性脑积水或脑干受压者可出现严重神经系统损害，常遗留后遗症，甚至导致死亡。早期识别，积极、恰当的治疗具有十分重要的意义。“,”Posterior reversible encephalopathy syndrome (PRES) is a clinico-neuroradiological entity affecting the posterior brain, i.e. occipital and parietal lobes. The syndrome are characterized by headaches, altered mental status, seizures, and visual disturbances. Although the pathogenesis remains unclear, endothelial dysfunction may be a key factor. The basic disease may play a crucial role in the incidence of PRES. In most cases, PRES resolves spontaneously and patients show both clinical and radiological improvements. In severe forms, PRES might cause substantial morbidity with sequel and even mortality, as a result of acute hemorrhage or massive posterior fossa edema causing obstructive hydrocephalus or brainstem compression. Early identiifcation, active and appropriate treatment is very important.