The correlation between the changes in pulmonary function and chronic cough in children with Mycoplasma pneumoniae pneumonia / 中华实用儿科临床杂志

ABSTRACT

Objective To discuss the correlation between dynamic changes in pulmonary function and chronic cough in 5-to-14-year-old children with Mycoplasma pneumoniae pneumonia(MPP)after acute period(about 2 weeks after admission). Methods One hundred and fifty - six hospitalized children diagnosed with MPP from Lianyungang Maternal and Child Health Care Hospital Affiliated to Yangzhou University from February 2014 to May 2017 were selected. According to the results of routine ventilatory pulmonary function before discharge(10-14 days in hospital;acute phase group),there were 50 patients with normal pulmonary function and 106 patients with abnormal pulmonary function. All patients continued to take oral azithromycin for 2 to 3 courses after discharge,and the indexes of lung function were dynamically tracked in 1 month(1-month group)and 2 months(2-month group)in the group of abnormal lung function after leaving the hospital,and the incidences and causes of chronic cough were followed up. Results (1)There were 106 cases with abnormal pulmonary function in 156 cases with MPP in acute phase group,and the rate of incidence was 67. 95%. Twenty-seven(29. 35%)out of 97 children were still abnormal in pulmonary functional testing 1 month after leaving hospital( 1-month group). Among the 27 cases,about 18. 52%(5/27 cases) of them still did not return to normal 2 months after discharge( 2-month group ). There were significant differences in the occurrence of abnormal pulmonary function among 3 groups mentioned above(χ2 ＝162. 64,P<0. 001).(2)Ratios of measured values and predicted ones of forced vital capacity( FVC ),forced expiratory volume in one second (FEV1 ),peak expiratory flow(PEF)and maximum mid-expiratory flow(MMEF 25% -75%)in the lung function of 2-month group after the acute phase of MPP were significantly higher than those of 1-month group and acute phase group,and the values of 1 -month group were better than those in acute phase one,which were statistically different among 3 groups(P<0. 01).(3)The rate of occurrence of chronic cough in normal lung function group was about 18. 00%(9/50 cases),and in abnormal pulmonary function group,it was about 70. 75%(75/106 cases). There was a significant difference between them(χ2 ＝35. 96,P<0. 05). Abnormal pulmonary functions were the influencing factors of chronic cough(r＝0. 55,P<0. 01).(4)There were 5 cases with upper airway cough syndrome(UACS)and 4 cases with post-infection cough(PIC)found in the normal lung function group. By contrast,75 cases suffered from chronic cough in abnormal pulmonary functions group,of which 36 cases with cough variant asthma( CVA),24 cases with UACS,8 cases with comorbidity of CVA and UACS and 7 cases with PIC. Conclusions Abnormal lung function after acute period of MPP may last 4 to 8 weeks,or probably even longer. In normal lung function group,UACS is the most common cause,then followed by PIC. On the contrary,the main cause of chronic cough in abnormal pulmonary function group is CVA,followed by UACS. Chronic cough is related to abnormal lung function after acute phase of MPP.