儿童坏死性肺炎临床特征及危险因素分析

目的: 探讨儿童坏死性肺炎的临床特点及危险因素。方法: 回顾性分析2016年1月至2020年1月在首都儿科研究所附属儿童医院呼吸科住院的218例重症肺炎患儿的病例资料，根据是否发生肺坏死将患儿分为坏死性肺炎(necrotizing pneumonia, NP)组(96例)和非坏死性肺炎(non-necrotizing pneumonia, NNP)组(122例)，比较两组临床特征(营养不良、热程、住院时间、影像学表现、治疗及转归随访情况)、实验室检查白细胞、中性粒细胞比例、血小板计数(platelet，PLT)、C-反应蛋白(C-reactive protein，CRP)、降钙素原(procalcitonin，PCT)、D-二聚体(D-dimer)、乳酸脱氢酶(lactate dehydrogenase，LDH)]和支气管镜下表现的差异，对坏死性肺炎相关临床危险因素进行Logistic回归分析，进一步通过受试者工作特征(receiver operating characteristic, ROC)曲线确定各指标最大诊断价值的临界值。结果: 两组患儿在年龄、性别、病原学分类、支气管镜下表现的差异无统计学意义(P>0.05)，NP组患儿的影像学吸收时间长于NNP组(P < 0.05)。两组患儿营养不良、热程、住院时间、白细胞计数、中性粒细胞比例、CRP、PCT、D-dimer等指标的差异有统计学意义(P < 0.05)。6岁以下患儿的影像学吸收时间短于6岁以上者，病程10 d内进行支气管肺泡灌洗治疗的患儿影像学吸收时间短于病程10 d以上者，混合感染组的影像学吸收时间明显长于单一病原感染组。对两组病例进行Logistic回归分析发现，热程、住院时间、CRP、PCT、D-dimer是继发肺坏死的危险因素(分别为P < 0.001、P < 0.001、P < 0.001、P=0.013、P=0.001)。绘制热程、CRP、PCT、D-dimer的ROC曲线，发现当热程>11.5 d、CRP>48.35 mg/L、D-dimer>4.25 mg/L时，对于预测肺坏死的发生有一定诊断价值ROC曲线下面积(area under ROC curve, AUC)分别为0.909、0.836、0.747，P均 < 0.001]。结论: 儿童坏死性肺炎的热程、住院时间长，混合病原感染的影像学吸收时间明显长于单一病原感染；与6岁以上组患儿及病程>10 d组患儿相比，6岁以下以及病程10 d内的患儿行电子支气管镜肺泡灌洗的疗效更具优势；炎症指标CRP、PCT、D-dimer明显升高，热程、CRP、PCT、D-dimer是重症肺炎继发肺坏死的危险因素，热程>11.5 d、CRP>48.35 mg/L、D-dimer>4.25 mg/L对诊断坏死性肺炎有较高预测价值。

Analysis of clinical features and risk factors of necrotizing pneumonia in children

Objective: To investigate the clinical characteristics and risk factor analysis of necrotizing pneumonia in children. Methods: A retrospective study was used to analyze the case data of 218 children with severe pneumonia hospitalized in the Department of Respiratory Medicine, Children's Hospital of Capital Institute of Pediatrics from January 2016 to January 2020, and they were divided into 96 cases in the necrotizing pneumonia group (NP group) and 122 cases in the non-necrotizing pneumonia group (NNP group) according to whether necrosis of the lung occurred. The differences in clinical characteristics (malnutrition, fever duration, hospitalization time, imaging performance, treatment and regression follow-up), laboratory tests leukocytes, neutrophil ratio, platelet (PLT), C-reactive protein (CRP), procalcitonin (PCT), D-dimer, and lactate dehydrogenase (LDH)] and bronchoscopic performance between the two groups were compared, and Logistic regression analysis of clinical risk factors associated with necrotizing pneumonia was performed to further determine the maximum diagnostic value of each index by subject operating characteristic curve (ROC). The critical value of each index was further determined by the ROC. Results: The differences in age, gender, pathogenic classification, and bronchoscopic presentation between the two groups of children were not statistically significant (P>0.05); whereas the imaging uptake time of the children in the NP group was higher than that in the NNP group (P < 0.05). The differences in malnutrition, fever duration, length of stay, white blood cell count, neutrophil ratio, CRP, PCT, and D-dimer were statistically significant between the two groups (P < 0.05). The imaging uptake time was lower in children under 6 years of age than in those over 6 years of age, and the imaging uptake time for bronchoalveolar lavage within 10 d of disease duration was lower than that for those over 10 d; the imaging uptake time was significantly longer in the mixed infection group than that in the single pathogen infection group. Logistic regression analysis of the two groups revealed that the duration of fever, hospital stay, CRP, PCT, and D-dimer were risk factors for secondary pulmonary necrosis (P < 0.001, P < 0.001, P < 0.001, P=0.013, P=0.001, respectively). The ROC curves for fever duration, CRP, PCT, and D-dimer were plotted and found to have diagnostic value for predicting the occurrence of pulmonary necrosis when fever duration >11.5 d, CRP >48.35 mg/L, and D-dimer > 4.25 mg/L area under ROC curve (AUC)=0.909, 0.836, and 0.747, all P < 0.001]. Conclusion: Children with necrotizing pneumonia have a longer heat course and hospital stay, and the imaging uptake time of mixed pathogenic infections is significantly longer than that of single pathogenic infections. Children with necrotizing pneumonia under 6 years of age have more advantageous efficacy of electronic bronchoscopic alveolar lavage within 10 d of disease duration compared with children in the group over 6 years of age and children in the group with disease duration >10 d. Inflammatory indexes CRP, PCT, and D-dimer are significantly higher. The heat course, CRP, PCT, and D-dimer are risk factors for secondary lung necrosis in severe pneumonia. Heat course >11.5 d, CRP >48.35 mg/L, and D-dimer >4.25 mg/L have high predictive value for the diagnosis of necrotizing pneumonia.