RESUMO
Objective To study the clinical features and spirometry of children with chronic cough and positive findings by bronchial provocation test.Methods Four hundred and fifty children with chronic cough from 3 hospitals of Shanghai Children's Medical Center Affiliated to Shanghai Jiao Tong Medical University School of Medicine,Gong Li Hospital of Pudong New Area,Pudong Hospital,were enrolled in this study from December 2012 to December 2014,and among them,373 cases completed the questionnaires,spirometry and bronchial provocation test.The differences in clinical features and spirometry between the bronchial provocation test positive group and negative group were compared.And the further evaluation of their clinical value was performed.Results Two hundred and thirty-six cases of children with bronchial provocation tests positive showed much higher rate of dry [72.03％ (170/236 cases)] and night cough[58.90％ (139/236 cases)] than those in the negative group[27.00％ (37/137 cases),22.63％ (31/137cases)],and the differences were significant (x2 =71.154,45.973,all P ＜0.01).Children in positive group also had higher morbidity of eczema[52.12％ (123/236 cases)],allergic conjunctivitis [24.15％ (57/236 cases)] and inhaled allergy history[40.25％ (95/236 cases)] than those in negative group[32.85％ (45/137 cases),10.95％ (15/137cases),18.98％ (26/137 cases)],and there existed significant differences (x2 =13.006,9.701,17.904,all P ＜0.01).And they also had higher asthma heredity [18.22％ (43/236 cases)] than that in negative group [9.49％(13/137 cases)],and the difference was significant (x2 =5.179,P =0.023);with worse small airway function [50.85％ (120/137 cases) vs 36.50％ (50/137 cases)] (x2 =7.197,P =0.007).For further study,the sensitivity and specificity for dry cough were both high(72.03％ and 72.99％).For specificity,family history was the most highest one (90.51％),and night cough and allergic conjunctivitis were also high.Conclusions Pulmonary function tests to reflect small airway function abnormalities,combined with a family history of asthma and chronic cough in children related to eczema,allergic conjunctivitis,and inhalation allergy history clinical features,can better predict airway hyperresponsiveness.