Analysis Of Clinical Features Of Bronchiolitis Obliterans In Children

Objective:Postinfectious bronchiolitis obliterans(BO) designates a clinical syndrome of chronic airflow obstruction associated with inflammatory and fibrotic changes in the small airways.BO is usually observed after infection in children,with the clinical presentation of recurrent or persistent wheezing and coughing,worsening by activity.The quality of patients' life are seriously affected.The definite diagnosis depends on lung biopsy,however,the use of lung biopsy is limited since it is an invasive method for the infants.The initial clinical and radiological presentation does not differ from acute bronchiolitis or viral pneumonia,which makes it is difficult for clinicians to diagnose BO at its early stage.Fortunately,high-resolution computed tomography contributes to the elavated diagnostic rates of of BO in last few years.The aim of this study was to determine the etiology,clinical and radiological features and of postinfectious BO in children,try to identify the prognostic factors and proper treatment. Method:We undertook a retrospective review of the medical records of 14 patients with a clinical and radiological diagnosis of postinfectious BO who were diagnosed and treated in our department and then followed up between March,2006 to the December,2008,and the patients diagnosised as pneumoniae with wheezing.BO are diagnosed by follwing clinical features and HRCT findings:(1) a previously documented acute lung infection with persistence of respirarory symptoms;(2) wheezing and(or) crackles;(3) a relatively mild impairment image of lung in chest x-ray that not parrallel with their serious clinical features.(4) HRCT features indicate mosaic perfusion pattern,uneven of ventilation,air trapping on expiration,bronchiectasia, and bronchial wall thickening.(5) Chest radiograph persents hyperlucency of single lung.(6) pulmonary funtion tests confirm airway obstruction.(7) exclusion of other causes of chronic obstructive pulmonary diseses.Furthermore,the wheezing patients who was diagnosed as pneumoniae would be excepted for BO.All documents of patients were analysed retrospectively.The medical records cover the sex, age,history,temperature,clinical symptom,physical sign,blood routine, CRP,hepatic function,ases of cardiac muscle,immunity,serum antibodies of mycoplasma pneumoniae,respiratory syncytial virus, cytomegalovirus DNA,serum hepatitis virus,the results of hemoculture and sputum culture,the history of treatment and the prognosis.All of the 14 patients were Followed-up,mornitering the respiratory tract infection, clinical features,treatment and lung function changes.Meanwhile,14 patients who have been diagnosed as wheezing pneumoniae in our department were selected as control.The parameters above of two groups were matched and compared.Results:Our study found all of 14 patients had been infected. Bacterium,viruses,mycoplasma pneumonia and chlamydia are common etilogical pathogen.Parts of them were even infected by more than one agents.Following are pathogens involved in the infection,according to patients' data:Bacillus coli(7.1%),baumanii and pseudo-yeast fungus (7.1%),cytomegalovirus(14.2%),hepatitis B(14.2%),mycoplasma pneumoniae(21.4%),chlamydia(14.2%).The agents of dieases are as the same as the conditon in pneumoniae.All patients' chest CT presented mosaic perfusion pattern(100%),accompanying with bronchiectasis and membrana pleuralis thickening(35.7%),consolidation and minification of lung(7.1%) while all presentations of CT in wheezing pneumoniae revealed fine.Three out of 14 patients quit the rearch.Symptoms and physical signs released in 10 of 11 patients without sports(90.9%).As for the pulmonary function changes at the end of the study,only one of 7 was mixed obstruction(14.3%),one out of 7 showed severe obstruction (14.3%),2 out of 147 presented median obstruction(28.5%) and 3 out of 7 showed slight obstruction(42.9%).The values of Ti/Te,TPTEF/TE and VPTEF/VE were much less than the normal value.All of these patients were treated with methylprednisolone,budesonide and salbutamol,while being treated with antibiotics if there were identifed infection evidences in hospital.9 of 11 patients were administrated with oral hormone and 7 of 11 patients inhaling budesonide and salbutamol after leaving the hospital.All of them took up macrolide.3 out of 14 BO patients quit the follow-up.Excepting for sports,10 out of 11 BO patients showed recovery(09.9%),only 1 out of 11 BO patients showed no improvement at the end of the study(9.1%).All of them are alive.Conclusion:The results of our study indicated that in children,BO are mostly postinfectious and the common pathogens are bactirum, viruses,mycoplasma and chlamydia.BO are diagnosised under the 2 years old infants during winter and spring.The CT of lung at the early stage of the disease shows consolidation while uneven of ventilation and mosaic perfusion pattern could only be observed later.The values of Ti/Te, TPTEF/TE,VPTEF/VE were less than the common and the pulmonary function shows the obstructive ventilation.The occurrences of pulmonary artery protrusion and mechanical ventilation may predict the bad prognosis.If the cough and wheezing stays more than 4 weeks after severe low respiratory,the CT detection should be taken in order to clearify the diagnose.The further study is necessary for revealing the value of pulmonary function test in predicting BO in patients with pneumonia with wheezing.No significant diference in clinical features was identified in patients who took 12 months or more than 12 months of oral hormone,respectively.The prognosis is not usually fine if the care of patients(especially lung care) are performed closely.Base on this study, the research suggests that the length of oral hormone is less than 1 year, and the different effects of oral hormone,inhalation of drugs and the combination treatments will be investigated in near future to evaluate the effect of inhalation of drugs,such as budesonide and salbutamol at recovery stage,and try to reduce the side effect of cortisteroid.