Negrini B, Kelleher K J, Wald E R
Department of Pediatrics, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
Pediatrics. 2000 Feb;105(2):316-9. doi: 10.1542/peds.105.2.316.
Aseptic meningitis is often reported to be characterized by a mononuclear cell predominance in the cerebrospinal fluid (CSF), whereas bacterial meningitis is characterized by a polymorphonuclear (PMN) cell predominance. In contrast, other studies suggest that PMNs can be the most prevalent cell in early aseptic meningitis followed by a shift to mononuclear cells within 24 hours. These contradictory reports may lead to uncertainty in the diagnosis and treatment of meningitis.
To assess 1) the characteristics of the CSF differential in aseptic versus bacterial meningitis, 2) the influence of duration of illness on the CSF differential, and 3) the role of the CSF differential in discriminating between aseptic versus bacterial meningitis.
A retrospective chart review was conducted of all cases of meningitis in children >30 days of age hospitalized during the peak months for enteroviral meningitis (April to October) between 1992 to 1997. Cases of aseptic meningitis were defined as having at least 20 white blood cells/mm(3) and the absence of bacterial growth on culture. Patients were excluded if they received antibiotic therapy within the previous 5 days. Cases of bacterial meningitis were defined as having a positive culture of the CSF or the presence of a CSF pleocytosis with positive cultures of the blood. CSF variables including white blood cell differential and time from the onset of symptoms to the performance of a lumbar puncture were analyzed. PMNs were considered to be predominant when the percentage of neutrophils added to juvenile forms was >50% of cells.
One hundred fifty-eight cases of meningitis were reviewed: 138 were aseptic and 20 were bacterial. The patients ranged in age from 30 days to 18 years; 61% were male. Fifty-seven percent of cases of aseptic meningitis had a PMN predominance. The percentage of PMNs in the CSF in patients with aseptic meningitis was not statistically different for patients who had a lumbar puncture performed either within or beyond 24 hours of the onset of symptoms. Fifty-one percent of the 53 patients with aseptic meningitis and duration of illness >24 hours had a PMN predominance. The ability of a PMN predominance to differentiate between aseptic and bacterial meningitis was assessed. The sensitivity of a PMN predominance for aseptic meningitis is 57% whereas the specificity is 10%. The positive predictive value of a PMN predominance for aseptic disease is 81% but the negative predictive value is 3%. Alternative definitions of PMN predominance from 60% to 90% were not useful as a clinical indicator of bacterial disease.
The majority of children with aseptic meningitis have a PMN predominance in the CSF. The PMN predominance is not limited to the first 24 hours of illness. Because the majority of children with a PMN predominance during enteroviral season will have aseptic disease, a PMN predominance as a sole criterion does not discriminate between aseptic and bacterial meningitis.
无菌性脑膜炎常被报道其脑脊液（CSF）以单核细胞为主，而细菌性脑膜炎则以多形核（PMN）细胞为主。相比之下，其他研究表明，PMN可能是早期无菌性脑膜炎中最常见的细胞，随后在24小时内转变为单核细胞。这些相互矛盾的报道可能导致脑膜炎诊断和治疗的不确定性。
评估1）无菌性脑膜炎与细菌性脑膜炎脑脊液细胞分类的特征，2）病程对脑脊液细胞分类的影响，3）脑脊液细胞分类在区分无菌性脑膜炎与细菌性脑膜炎中的作用。
对1992年至1997年肠道病毒脑膜炎高发月份（4月至10月）住院的30天以上儿童的所有脑膜炎病例进行回顾性病历审查。无菌性脑膜炎病例定义为脑脊液白细胞至少20个/mm³且培养无细菌生长。如果患者在过去5天内接受过抗生素治疗则被排除。细菌性脑膜炎病例定义为脑脊液培养阳性或脑脊液细胞增多且血培养阳性。分析脑脊液变量，包括白细胞分类和从症状出现到进行腰椎穿刺的时间。当中性粒细胞与幼稚细胞百分比之和>细胞总数的50%时，认为PMN占优势。
共审查了158例脑膜炎病例：138例为无菌性脑膜炎，20例为细菌性脑膜炎。患者年龄范围为30天至18岁；61%为男性。57%的无菌性脑膜炎病例以PMN为主。无菌性脑膜炎患者在症状出现后24小时内或超过24小时进行腰椎穿刺，其脑脊液中PMN的百分比无统计学差异。53例病程>24小时的无菌性脑膜炎患者中，51%以PMN为主。评估了PMN占优势在区分无菌性和细菌性脑膜炎中的能力。PMN占优势对无菌性脑膜炎的敏感性为57%，而特异性为10%。PMN占优势对无菌性疾病的阳性预测值为81%，但阴性预测值为3%。将PMN占优势的替代定义设定为60%至90%，对作为细菌性疾病的临床指标并无帮助。
大多数无菌性脑膜炎儿童的脑脊液以PMN为主。PMN占优势并不局限于疾病的最初24小时。由于在肠道病毒流行季节，大多数PMN占优势的儿童患有无菌性疾病，因此仅以PMN占优势作为标准无法区分无菌性脑膜炎和细菌性脑膜炎。
