ABSTRACT
Objective To understand the causes and the ratio of cause constituents in children with chronic cough in Beijing. Methods Patients with chronic cough treated at respiratory clinic of the Children' s Hospital Affiliated to Capital Institute of Pediatrics from May 2009 to April 2011 were included in this study. Etiologic diagnostic procedure suggested for children by the Subspecialty Group of Respiratory Diseases,the Society of Pediatrics,Chinese Medical Association in 2008 was implemented to manage the patients. After three - month follow - up,the etiological data was analyzed. Results Totally 213 patients with chronic cough aged 1. 1 to 14. 0 years old were enrolled,inclu-ding 40 cases(18. 8% )aged≤3 years old,134 cases(62. 9% )aged ﹥ 3 to 6 years old,and 39 cases(18. 3% ) aged ﹥ 6 years old. The majority of patients with positive allergen tests were sensitized to inhaled allergens. One child had positive result in 24 - hour esophageal pH monitoring,but his cough didn't respond well to the specific treatment for gastroesophageal reflux,so he wasn't diagnosed as gastroesophageal reflux cough. The 4 leading causes of the 213 pa-tients with chronic cough were cough variant asthma(CVA)in 92 cases(43. 2% ),CVA associated with upper airway cough syndrome(UACS)in 57 cases(26. 8% ),UACS in 28 cases(13. 2% ),respiratory infection and post - infec-tion cough(PIC)in 26 cases(12. 2% ),while other causes were found in 8 cases(3. 7% ),and unknown etiology in 2 cases(0. 9% ). The incidence of CVA ranked top 1 in all the 3 age groups,followed by PIC in ≤3 years old group, while CVA associated with UACS in the other 2 age groups. Conclusions CVA,CVA associated with UACS,UACS and PIC were the 4 leading causes for children with chronic cough in Beijing. Children in different age groups had dif-ferent constituents ratio of causes of chronic cough.
ABSTRACT
Objective To develop a convenient reverse transcription PCR(RT-PCR)method for identifying genotypes of human metapneumovirus(hMPV)from clinical samples.Methods According to the gene sequences of hMPV G with different genotypes,the A and B genotype specific primers were designed.A diplex RT-PCR was applied to identify different genotypes according to the molecular weight of PCR products in agarose gel.37 clinical samples were detected through this method.Results It was convenient to distinguish different genotypes of hMPV(383 bp for A and 284 bp for B)by the diplex RTPCR,and there was no non-specific amplification for common respiratory viruses.so it meant that the specificity of primers was good.The results of genotyping 37 clinical samples showed that 20 samples were identified as genotype A by both sequence analysis of M gene and diplex RT-PCR,whereas 17 samples were identified as genotype B by sequence analysis of M gene.but in these 17 samples 14 samples were identified as genotype B by the diplex RT-PCR and remaining 3 samples could not be genotyped because there was no PCR product after amplification.The consistency rate for these two methods Was 91.9%[(20+14)/37].Conclusion The method of diplex RT-PCR Was developed successfully and can be used for identify genotypes of hMPV.