Clinical Characteristics Of Mycoplasma Pneumoniae Pneumonia In Infants And Young Children

Objective: To investigate the clinical characteristics of Mycoplasma pneumoniae pneumonia in infants and young children.Methods: 284 MPP children hospitalized in the Fourth Affiliated Hospital of China Medical University from June 2016 to June 2017 were collected.According to age,68 cases were divided into infants and young children group(0~3 years old)and 216 cases into elder group(3~14 years old).All the children in the group received venous blood for examination within 24 hours of admission and imaging examination.The clinical data of the two groups were collected,including age,sex,clinical symptoms,lung signs,extrapulmonary complications,laboratory testing and other indicators for statistical analysis.Result:1.The average fever duration in infants and young children group was significantly shorter than that in elder group(3.8±2.5 d),and the difference was statistically significant(P<0.05).The incidence of non-fever,low-fever,moderatefever,high-fever and super-high-fever in infant group were 19.1%,20.6%,39.7%,17.7% and 2.9% respectively.Compared with the elder group,the proportion of non-fever and low-fever in infants and young children group was significantly higher than that in elder group,and the proportion of high-fever was significantly lower than that in elder group(P<0.05).There was no significant difference in the proportion of moderate and superhigh heat.2.The incidence of wet cough,wheezing,lung rale and wheezing in infants and young children group was 63.2%,26.5%,86.8% and 38.2% respectively,and that in elder group was 26.9%,2.3%,69.9% and 6.5% respectively.Comparing the two groups,it was found that the proportion of wet cough,wheezing,lung rale and wheezing in infants and young children group was significantly higher than that in elder group(P<0.05).3.Extrapulmonary injury accounted for 41.2% in infants and young children group and 37.5% in elder group.The incidence of vomiting and diarrhea,abnormal myocardial zymogram,,blood system involvement,skin mucosa and liver involvement in infant group were 33.8%,29.4%,7.4%,5.9% and 4.4%,respectively.The results showed that the proportion of vomiting,diarrhea and abnormal myocardial zymogram in infants and young children group was significantly higher than that in elder group(P<0.05).There was no significant difference in liver involvement,skin mucosa damage and blood system involvement.Urinary system injury,nervous system involvement were only found in the elder group.4.The levels of hs-CRP,serum LDH and plasma D-dimer in infants and young children group were significantly lower than those in older group(P<0.05).There were no significant differences in blood routine white blood cell count,platelet count,PCT between infants and young children group and older group.The positive rate of MP antibody in the infants and young children group was significantly lower than that in the elder group within 7 days of onset,and significantly higher than that in the elder group over 10 days(P<0.05).There was no significant difference in the results of 7~10 days.5.Lobular parenchymal infiltration was the most common imaging manifestation in infants and young children group(60.3%).The proportion of parenchymal infiltration above lung segment and pleural effusion in infants and young children group was significantly lower than that in older group(P<0.05).There were no significant differences in pulmonary interstitial infiltration,lobular parenchymal infiltration and hilar opacity between the two groups.6.The average hospitalization days and the number of severe MPP cases in the infants and young children group were significantly lower than those in the elder group(P<0.05).There was no significant difference in the use of glucocorticoids.There were no cases treated with fiberoptic bronchoscopy and immunoglobulin in infant group.7.Compared with the elder group,the increase of serum LDH and plasma D dimer in the infants and young children group was significantly lower than that in the elder group.Bilateral lung involvement was more common in the elder group,and the inflammatory absorption rate was significantly higher than that in the elder group(P<0.05).There was no pleural effusion or atelectasis in the infants with lobar pneumonia.Conclusion:MPP in infants and young children has a short duration of fever,and moderate to low fever is the most common manifestation.Most of them have wet cough.The incidence of wheezing is high.The lung rale and wheezing are obvious.Extrapulmonary complications are mainly manifested in digestive system such as vomiting and diarrhea.Elevated myocardial enzymes are more common in infants and young children.Inflammatory index were lower than the elder children.MP antibody production was delayed.Bronchopneumonia and interstitial pneumonia were the main imaging features,and bilateral lung was easily involved.MPP in infants and young children is milder than that in elder children.Severe MPP cases are relatively rare and the prognosis is good.