Analysis Of Epidemiology,clinical Features And Severe Cases Of Children With Influenza In Bengbu Area

Objective:To compare the epidemiology and clinical features of A with B type of influenza in children in Bengbu area,and to explore the risk factors and the change of immune cells in severe cases of influenza.Method:The data of 134 children with influenza who were hospitalized and treated in our hospital from November 2017 to November 2018,which include general information,clinical manifestations,laboratory results,imaging results,treatment processes,disease outcomes,etc.After collecting nasopharyngeal secretions,the type of virus infected by the child was diagnosed and analyzed by immunofluorescence.After collecting blood samples,flow cytometry was used to detect the proportion of subgroups of the T-lymphocytes,B-lymphocytes and NK cells in the peripheral blood of severely ill children.The subgroups of lymphocytes from 10 healthy childrenin our clinic were used as control group to observe changes in the immune function of cells in children with severe influenza.Data were analyzed using SPSS 22.0 software to study the characteristics of influenza and the risk factors of severe cases.Results:1.Among 134 hospitalized children with influenza,90 cases?67.15%?had influenza A,44 cases?32.85%?had influenza B;24 patients met the diagnostic criteria for severe influenza,23 of whom were influenza A,significantly higher than those with influenza B?P=0.001?.December 2017 is the peak period of influenza B,and February 2018 is the peak period of influenza A.The main manifestations of this flu were fever,cough,and nasal discharge.Patients with a peak body temperature above39?had more cases of influenza A?79/90,87.78%?.Children with influenza A were more likely to have symptoms of gasping?33/90,36.67%?,dyspnea?16/90,17.78%?,and respiratory failure?9/90,10.00%?.Influenza A virus was more common in the patients that the white blood cell count in peripheral blood is higher than 10×10⁹/L?29/90,32.22%,P<0.05?,and increased neutrophil ratio were more common in influenza A virus infection?34/90,37.78%,P<0.05?.Among the children with influenza A,38 cases?42.2%?had elevated C-reactive protein,and 27 cases?30.00%?had elevated creatine kinase-myocardial isoenzyme?CK-MB?;the incidences of both indicators were higher than that of children with influenza B?P<0.05?.The mixed infection rate of influenza study population was 29.85%?40/134?,the mixed infection rate of mycoplasma pneumoniae was 19.40%?26/134?,the mixed infection rate of respiratory syncytial virus was 5.97%?8/134?,the mixed infection rate of adenovirus was 2.24%?3/134?,and the mixed infection rate of bacteria was 2.24%?3/134?.There was no statistical difference in the mixed infection rate of type a and type b viruses?P>0.05?.The imaging findings of children with influenza A and B after hospitalization were mainly based on the increased and thickened texture of hilum of lung and the small patch shadow.Nine patients who received ventilator-assisted treatment through tracheal intubation were children with influenza A virus,higher than those infected with influenza B virus?P<0.05?.2.Univariate logistic regression analysis shows that admitted patients with increased neutrophil ratio,decreased lymphocyte ratio,increased CRP,and suffering from underlying disease may be risk factors for severe symptoms?P<0.05?.Multivariate logistic regression analysis shows thatthere is a collinearity between the increase in the proportion of neutrophils and the decrease in the proportion of lymphocytes?tolerance?0.1,variance expansion factor VIF?10?,and finally patients with underlying diseases,decreased lymphocyte percentage and increased CRP values entered the model?P<0.001?,where the decrease in lymphocyte percentage contributed the most to the model??=0.72?,followed by patients with underlying disease??=0.51?and patients with increased CRP values??=0.32?.3.Compared with the healthy control group,the proportion of CD₃⁺,CD₄⁺,CD₈⁺and NK cells decreased?P<0.01?;the proportion of B-lymphocytes in the severe group was significantly higher than that of the healthy control group?P<0.01?;there was no statistical significance in the difference of CD₄⁺/CD₈⁺between severe group and healthy control group?P>0.05?.Conclusions:1.Children are more likely to be infected with influenza A and B virus in autumn and winter.The main symptoms are fever,cough and nasal discharge.After infection with influenza A virus,it is more prone to high fever and severe cases?such as respiratory failure?.It is necessary to pay attention to the identification in the clinic so that it can be diagnosed early and treated in time.2.The white blood cell count,neutrophil ratio and CRP become higher after infection with influenza A virus;the underlying disease,the decrease of lymphocyte ratio and the increase of CRP value are risk factors for severe symptoms after infection with influenza A virus.In clinical practice for children with influenza A virus,we should pay attention to find evidences of infection with bacteria and actively use antibiotics.3.In severe cases of children with influenza A,a large number of T-lymphocytes are consumed and depleted,activated B-lymphocytes are involved in the clearance of viruses,NK cells are destroyed in large amounts,and the cellular immune function are disordered.