幕下原发性中枢神经系统血管炎五例临床分析

A clinical analysis of 5 patients with infratentorial primary angiitis of central nervous system

目的总结5例幕下原发性中枢神经系统血管炎（PACNS）的临床及影像学特点，以提高对该疾病的认识。方法收集2015年海军总医院神经内科就诊的5例幕下PACNS，总结其临床、影像学特点。结果5例患者均为男性，中位发病年龄34岁，临床表现为头晕5例，头痛2例，行走不稳3例，面部麻木2例，构音障碍1例。腰椎穿刺检查4例脑脊液（CSF）压力升高（190～245cmH2O，1cmH20=0．098kPa），2例白细胞计数轻度增高[（12～28）×10^6／L]，3例CSF蛋白轻度升高（540～979mg/L），3例IgG指数轻度增高（0．84～1．45）。MRI检查显示病灶多位于桥脑（4／5），其次为桥臂（2／5）、小脑（2／5）、中脑（1／5），单侧4例，双侧1例，5例患者的病灶均有不同程度水肿及占位效应，MRI增强显示病灶片状强化，其中2例伴有脑膜强化。磁共振波谱（MRS）检查显示4例胆碱（Cho）峰增高，3例N-乙酰天冬氨酸（NAA）峰下降，1例出现脂质峰，1例出现乳酸峰。4例行动脉自旋标记（ASL）成像，4例未见病灶高灌注。3例行磁敏感加权成像（SWI），2例可见病灶处微出血信号，1例未见异常。1例行磁共振血管成像（MRA），未见血管狭窄。1例行数字减影血管造影（DSA）检查，提示颅内动脉多发狭窄。2例行脑组织活检，病理提示血管炎。5例均予大剂量甲泼尼龙冲击治疗，1例加用环磷酰胺。5例随访预后均良好。结论幕下PACNS多发于青、中年男性，病灶多累及桥脑，其次为桥臂、小脑、中脑，单侧发病多见。SWI发现病灶内出血／微出血有助于明确诊断。ASL未见高灌注可与恶性肿瘤鉴别。幕下病变脑活检临床应用受限，临床结合影像检查有助于PACNS诊断。

Objective To explore the clinical characteristics of infratentorial primary angiitis in central nervous system （PACNS）. Methods A total of 5 cases diagnosed as infratentorial PACNS in the neurology department of Navy General Hospital of PLA in 2015 were enrolled in the study. The clinical, imaging and pathological data were collected and analyzed. Results All the 5 cases were male with the median onset age of thirty-four. Five cases presented with dizziness, two with headache, three with walking unstable, two with facial numbness and one with dysarthria. Rising pressure of cerebrospinal fluid （CSF） （ 190 -245 cmH2O, 1 cmH2O= 0. 098 kPa） was found in 4 cases by the lumbar puncture, mildly increased number of leukocyte in 2 cases [ （ 12 - 28 ）×10^6/L j , increased CSF protein in 3 cases （ 540 - 979 mg/L） and increased IgG index in 3 eases （0. 84 - 1.45）. Pons lesions were revealed by magnetic resonance imaging（MRI） in 4 cases, brachium pontis lesions in 2 cases, cerebellum lesions in 2 cases, one with midbrain lesion in 1 case, unilateral lesions in 4 cases and bilateral lesion in 1 case. Different degree of edema and mass effect were shown in all lesions by MRI. Patch like enhancement was found by contrast MRI in 5 cases and meningeal enhancement in 2 cases. Elevation of choline （Cho） peak was found by magnetic resonance spectroscopy （MRS） in 4 cases, reduction of N-acetyl aspartate （NAA） peak in 3 cases, appearance of lactate peak in 1 case and lipid peak in another case. Arterial spin labeling （ASL） was performed in 4 cases and no hyperperfusion was found. Susceptibility weighted imaging（SWI） was performedin 3 cases and microhemorrhage in the lesions was resonance arteriography（MRA） was performed in 1 found in 2 cases and normal in 1 case. Magnetic case and no stenosis was found. Digital subtraction arteriography（DSA） was performed in 1 case and multiple stenosis of the intracrauial arteries was showed. Two cases had taken the stereotactic brain biopsy and the histopathologic diagnosis was angiitis. Five cases were treated with methylprednisolone and cyclophosphamide was added on in 1 ease. Good prognosis was found in all cases. Conclusions Infratentorial PACNS mostly attacks middle-aged males. The lesions tend to locate in unilateral pons, brachium pontis, cerebellum and midbrain. Hemorrhage or microhemorrhage in lesions is often found by SWI and no hyperperfusion is shown by ASL, which would be useful to distinguish PACNS from malignant tumors. Given the limitations of brain biopsy in clinical practice, clinical and imaging features would be helpful to diagnose PACNS.