Objective:To understand the clinical characteristics of lower respiratory tract infection caused by mycoplasma pneumoniae (MP)in children. Methods:Clinical data of 211 in-patients diagnosed with mycoplasma pneumoniae-caused lower respiratory tract infections from the first respiratory ward of our hospital from Jan.2008 to Apr.2009 was analyzed retrospectively to figure out the feature of the patient’s age

clinical symptoms and signs

chest X-ray

pulmonary function and other laboratory results. Results:There was no significant difference between different gender in patients with mycoplasma pneumoniae-caused lower respiratory tract infection

among the patients

there were 71.1% of them were under 5 years of age

rate of patients under through cough

fever and wheezing were 98.6%

75.4% and 51.2% respectively. Rate of infants suffered from wheezing were significantly higher than older children (62.4% vs 39.2%

P=0.001)

rate of infants suffered from vomiting and diarrhea was higher than older children (35.8% vs 14.7%

P=0.000 1)

and rate of infants suffered from rash was higher than older children(14.7% vs 5.9%

P=0.037). There were 60.7% mycoplasma pneumoniae patients combined chlamydia pneumoniae (CP) infection

50.0% of them combined bacterial infection

and 26.9% of them combined virus infection. Pulmonary function tests indicated that there were 90.3%(65/72)patients developed airway obstruction in varying degrees

and there were 70.8% (17/24)patients suffered from airway hyper-responsiveness. Conclusion:Younger children are more susceptible to Mycoplasma pneumoniae-caused lower respiratory tract infection

and the most common symptoms of which were cough

fever and wheezing. Compared with older children

infants developed wheezing、vomiting、diarrhea and rash more probablely. Mycoplasma pneumoniae infection often combined with chlamydia pneumoniae infection

which might be the cause of airway obstruction and airway hyper-responsiveness.