小儿肺炎是以肺部受累为主的全身性疾病。病原体主要为细菌、病毒及支原体等。肺炎患儿除呼吸系统受累外,其它系统包括酶的活力、体内代谢等多方面都受到不同程度的影响。因此,它不是局部疾病,而是全身性疾病。肺炎的病理生理变化主要是由于缺氧、二氧化碳潴留而引起的全身代谢过程及重要脏器功能不同程度的变化。轻症肺炎只表现为肺部受累,而重症肺炎可引起心力衰竭、中毒性脑病、中毒性肠麻痹、消化道出血、DIC及呼吸衰竭等。中枢神经系统对缺氧及二氧化碳潴留较敏感,常因毛细血管扩张、血脑屏障功能降低、钠泵作用失调及脑细胞代谢紊乱而引起脑水肿。肺炎患儿的中枢神经系统变化不单纯表现为临床常见的中毒性脑病,还可表现为其他的中枢神经系统病症,如脑炎、脑膜炎、脑膜脑炎、脑脓肿、硬膜下积液、脑 Pediatric pneumonia is a systemic disease mainly involving the lungs. The main pathogens are bacteria, viruses and mycoplasma and so on. In addition to pneumonia children with respiratory involvement, other systems, including enzyme activity, metabolism and other aspects are subject to varying degrees of impact. Therefore, it is not a local disease, but a systemic disease. Pathophysiology of pneumonia mainly due to hypoxia, carbon dioxide retention caused by systemic metabolic processes and changes in vital organs of varying degrees. Mild pneumonia only manifests as pulmonary involvement, and severe pneumonia can cause heart failure, toxic encephalopathy, toxic intestinal paralysis, gastrointestinal bleeding, DIC and respiratory failure. Central nervous system is more sensitive to hypoxia and carbon dioxide retention, often due to telangiectasia, decreased blood-brain barrier function, dysfunction of sodium pump and brain cell metabolism caused by cerebral edema. Central nervous system changes in children with pneumonia are not simply manifested as clinical toxic encephalopathy, but also in other central nervous system disorders such as encephalitis, meningitis, meningoencephalitis, brain abscess, subdural effusion, brain