Abstract: Pneumonia is the leading cause of death in children under 5 years of age.The majority of pneumonia in children is community-acquired pneumonia（CAP）.Severe pneumonia in CAP is an important cause of death and affecting life quality in children.Domestic guidelines and norms all propose to assess the severity of childrens CAP based on age，clinical manifestations and images.We can turn empirical treatment into target treatment as soon as possible，when the pathogens are confirmed.Then the prognosis of the patients can be improved.This article will explain the clinical manifestations of severe pneumonia in children with different pathogens from the perspective of etiology，in order to deepen our understanding of severe pneumonia in children，so that early detection and treatment can be achieved，and the incidence and mortality of CAP in children can be reduced.

Key words: child, community-acquired pneumonia, severe pneumonia, pathogens

摘要： 肺炎是5岁以下儿童死亡的首要原因，绝大部分儿童肺炎为社区获得性肺炎（community acquired pneumonia，CAP），其中的重症肺炎是造成儿童死亡和影响生命质量的重要原因。国内指南和规范都提出根据儿童年龄、临床及影像学资料等评估儿童社区获得性肺炎的严重程度；及早明确病原，尽快使经验治疗转为目标治疗，改善预后。该文将从病原学角度，阐述不同病原感染所致的重症社区获得性肺炎的临床表现，加深对儿童重症肺炎认识，达到早发现、早治疗，降低儿童CAP的发病率和死亡率的目标。

关键词: 儿童, 社区获得性肺炎, 重症肺炎, 病原