Abstract: Objective  To study the clinical characteristics of severe mycoplasma pneumoniae pneumonia (MPP) in different monthage groups of infants. Methods  Retrospective analysis was utilized on the clinical data of the 65 infants who were enrolled by  Fujian Maternity and Children Health Hospital due to severe MPP between January 2014 and December 2016. Results  All of the 65 infants had the same symptoms of cough, wheezing and rale. Among different monthage groups, the proportions of male, mechanical ventilation, fever and the length of hospitalization were not significantly different. The levels of white blood cell count, platelet count (PLT) , Creactive protein, lactate dehydrogenase, MB isoenzyme of creatine kinase, Ddimer and alanine aminotransferase were different but had no statistical significance; As the monthage grows, the proportion of maximum body temperature (>39.0  ℃) and duration of fever (≥11 days) increased with statistical significance. The proportion of pulmonary complications（including atelectasis, emphysema, lung consolidation and hydrothorax）and Pediatric Critical Illness Score decreased with statistical significance among four groups. Prealbumin (PA) differ significantly among four groups, among which the 10 to 12 months group had a higher PA level than the others. Conclusion  The clinical features of severe MPP differs among infants of different monthages. Younger infants may have greater severity of MPP, more pulmonary complications and greater reduction of  prealbumin, while the elder infants have higher probability of duration of fever (≥11 days).

Key words: pneumonia, mycoplasma, mycoplasma pneumoniae, infants