MRI及脑脊液分析在中枢神经系统感染鉴别中的作用

Role of MRI and cerebrospinal fluid analysis in early differential diagnosis of central nervous system infection

目的探讨脑脊液（CSF）常规以及MRI特点对中枢神经系统感染性疾病鉴别诊断的意义。方法中山大学附属第一医院神经内科自2007年1月至2011年12月收住院并确诊中枢神经系统感染性疾病患者274例，其中病毒性脑／脑膜炎（病毒脑）166例、化脓性脑膜炎（化脑）45例、结核性脑膜炎f结脑）47例、隐球菌性脑膜炎（隐脑）16例；回顾性分析患者的MRI常规及增强扫描结果、CSF常规、血中性粒细胞百分比检查结果，采用逐步判别分析各项指标对4种感染的鉴别诊断价值。结果MRI扫描结果显示MRI异常患者76例（27．74％），其中病毒脑38例，化脑10例，结脑26例，隐脑2例；4种感染患者的CSF压力、蛋白质、氯化物、糖、中性粒细胞含量、血中性粒细胞百分比不同，差异有统计学意义（P〈0．05）。逐步回归分析筛选出CSF压力、蛋白质、氯化物、血中性粒细胞百分比、有无MRI病灶5项指标建立判别函数，诊断的总准确率为59．1％。诊断化脑的敏感性、特异性和准确率分别为24．4％、73．4％和65.3％，结脑为61．7％、80．6％和77．4％，隐脑为62．5％、56．9％和57．3％，病毒脑为67．5％、75．0％和70．4％。结论CSF压力、蛋白质、氯化物、血中性细胞百分比、有无MRI病灶对中枢神经系统感染性疾病的鉴别诊断最有意义，建立的判别函数对鉴别诊断具有一定价值。但临床上仍需病原学进行确诊。

Objective To investigate the significance ofcerebrospinal fluid pressure, cytology and biochemistry, and MRI features in the early differential diagnosis of central nervous system infections. Methods The clinical data of 274 patients with central nervous system infections （viral encephalitis/meningitis in 166 patients, purulent meningitis in 45, tuberculous meningitis in 47 and cryptococcal meningitis in 16）, admitted to our hospital from January 2007 to December 2011, were analyzed retrospectively. The cerebrospinal fluid pressure, cytology, biochemistry and MRI parameters were compared, and stepwise discriminant analysis was performed to evaluate the diagnostic value of these parameters in these four types of infections. Results Seventy six patients （27.74%） had abnormal MRI results; viral meningitis/encephalitis, purulent meningitis, tubercular meningitis and cryptococcal meningitis were found in 38, 10, 26 and 2 patients, respectively. Cerebrospinal fluid pressure, protein content, chloride and sugar level, and neutrophil percent were significantly different among the patients of four types of infections （P〈0.05）. And cerebrospinal fluid pressure, protein content, chloride level, neutrophil percent and MRI lesions were included in the discriminant functions by stepwise discriminant analysis; the total accurate rate of the discriminant functions for diagnosis was 59.1%. The sensitivity, specificity and accurate rate of the discriminant functions were 24.4%, 73.4% and 65.3% in purulent meningitis, 61.7%, 80.6% and 77.4% in tubercular meningitis, 62.5%, 56.9% and 57.3% in cryptococcal meningitis and 67.5%, 75.0% and 70.4% in viral meningitis/encephalitis, respectively. Conclusion Cerebrospinal fluid pressure, protein content and chloride level, neutrophil percent, and MRI lesions are important for differentially diagnosing central nervous system infection; the disscriminant functions produced by stepwise discriminant analysis are somewhat valuable for the differential diagnosis, and the final diagnosis still based on the etiology.