Abstract: Objective  To study the clinical characteristics of severe Mycoplasma pneumoniae pneumonia (MPP) in children， and to provide a basis for diagnosis and treatment. Methods  Retrospective analysis was performed on the epidemiological and clinical data of  the children who were hospitalized due to severe MPP from January 2014 to December 2015 in the hospital. Results  Among the 110 children who were hospitalized due to severe MPP， 43 cases were between 0 and 1 years old， 39 cases >13 years old， 18 cases >35 years  old and 10 cases  >5 years  old. The incidence of MPP varied with the seasons and was significantly highest in summer. With the growing of ages， the proportion of children with cough， with rale all decreased，the proportion of pulmonary complications（including lung abscess， hydrothorax，emphysema and pneumothorax）  and pathological change of right lung both increased（P＜0.05）.White blood cell count (WBC) differed significantly among four groups （P＜0.05）. Creactive protein(CRP)  and lactate dehydrogenase increased， but there were no statistical significance among different groups. A total of 110 patients were tested for other respiratory etiology， and coinfection was diagnosed in a total of 52 cases(47.3%). EB virus was the most common(23 cases，20.9%)， followed by cytomegalovirus (18 cases，16.4%). The coinfection features of severe MPP were different among children of different ages. The therapeutic effects of antibacterial agents， glucocorticoid and intravenous immunoglobulin in treating 110 severe MPP were positive. Conclusion  Severe MPP is sporadic throughout the whole year， with a higher incidence in summer. The clinical features of  severe MPP are different among children of different ages， and there are mixed infections of MPP and respiratory viruses. CRP and lactate dehydrogenase were significantly higher in children of severe MPP. Early recognition and combined treatment can reduce the occurrence of sequelae.

Key words: pneumonia, mycoplasma, signs and symptoms, therapy;children