High-resolution Computed Tomographic Findings Of Eosinophilic Granulomatosis With Polyangiitis:Comparison To Severe Asthma

Background: Eosinophilic Granulomatosis with Polyangiitis(EGPA)refers to a kind of rare vasculitis associated with Anti-neutrophil Cytoplasmic Antibody(ANCA)and Eosinophilic Lung Diseases.Early changes induced by EGPA mainly manifest as severe asthma and eosinophilia.Once progressed to vasculitis,several organs may be involved,including lungs,heart,gastrointestinal,kidneys,skin,central nervous system and peripheral nerves.For EGPA patients,the main initial symptom is asthma.As a result,they may be easily regarded as asthma patients and then treated with incorrect dose of corticosteroids.Consequently,they are misdiagnosed with asthma as their symptoms remit after the treatment,thereby delaying the treatment for EGPA and influencing the prognosis thereof.Therefore,this research aimed to study EGPA patients and severe asthma patients for their differences on thoracic manifestations by HRCT and clinical data.This research may help clinicians differentiate EGPA patients from severe patients before they show systemic symptoms of EGPA.Thereby,early diagnosis of EGPA may be possible.Objective: To discuss EGPA patients and severe asthma patients for their differences on clinical records,lung function,pathological biopsy result and thoracic manifestations by HRCT as well as the correlation of thoracic manifestations with clinical features and lung function.Methods: 96 EGPA patients and 85 severe asthma patients whose diagnoses were established after multi-disciplinary(clinical – imaging-pathology)discussions from November 2011 to August 2017 were included.Then retrospective analysis was conducted to compare their clinical symptoms and signs,lab and examination indexes,lung functions,thoracic manifestations by HRCT and other related information.Results:1.clinical characteristics: clinical data of 96 EGPA patients were collected,49males(51.0%)and 47 females(49.0%),the mean age being 45.90±12.79;clinical data of 85 severe asthma patients were collected,36 males(42.4%),49 females(57.6%),the mean age being 47.42±12.42.The EGPA group was significantly higher than the severe asthma group in terms of such parameters as time from onset of asthma-like symptoms to clinical diagnosis of EGPA or severe asthma,peripheral eosinophil count,EOS%,total IgE and erythrocyte sedimentation rate(ESR)(P < 0.05).Lung function examinations: the EGPA group was lower than the severe asthma group in terms of Predicted FVC%(P < 0.05).2.HRCT signs: the most common signs for both EGPA patients and severe asthma patients were thickened bronchial walls and air trapping signs;comparison between the two groups: compared with the severe asthma group,the EGPA group showed higher incidences of multiple ground-glass opacity,central lobular nodule,tree-in-bud sign,bronchial mucous plug,emphysema,consolidation shadow,bronchiectasis,mosaic sign,thickened interlobular septum and atelectasis(P < 0.05).3.Scoring of various signs: as for GGO,central lobular nodule,consolidation shadow,thickened bronchial wall,bronchiectasis,bronchial mucous plug,mediastinum or enlarged lymph nodes at hili of lungs and the total scoring of them,the EGPA group obtained a higher score than the severe asthma group,the difference between the two groups being of statistical significance(P < 0.05).4.For the 96 EGPA patients,their thoracic signs by HRCT were classified into3 types.These three types were compared with related clinical features respectively.The result showed that,pulmonary EGPA patients showed higher Predicted PEF %mean and Predicted MMEF% median than airway EGPA patients and mixed EGPA patients,the difference among these three groups being of statistical significance(P <0.05).Airway EGPA patients showed the lowest total IgE medial,followed by pulmonary EGPA patients and then mixed EGPA patients,the difference among these three groups being of statistical significance(P < 0.05).5.For EGPA patients,distribution features of the two HRCT imaging signs and related clinical features were compared.The result showed that,EGPA patients with randomly distributed changes had a lower predicted DLco% mean than those with peripherally distributed changes(P < 0.05),and EGPA patients with randomly distributed changes had a higher RV/TLC median than those with peripherally distributed changes(P < 0.05).6.Patients with randomly distributed changes mostly showed thickened bronchial wall,increased lung markings,central lobular nodule,tree-in-bud sign,bronchial mucous plug and bronchiectasis(P < 0.05).7.For EGPA patients,the total score of HRCT were negatively correlated with FEV 1/FVC,Predicted PEF% and Predicted MMEF%,the degree of correlation being of statistical significance(P < 0.05).Conclusion:1.HRCT may help to differentiate potential EGPA patients from severe asthma patients at an early stage.For patients presenting peripheral eosinophilia and increased total IgE,their thoracic manifestations by HRCT include multiple ground-glass opacity,central lobular nodules,tree-in-bud sign,bronchial mucous plug,emphysema and consolidation shadow;in particular,they may show thickened bronchial wall and expiratory air trapping signs.With these signs,it is more likely for clinicians to diagnosis EGPA.2.In the three pattern of EGPA in chest HRCT,the airway and mixed patterns were associated with the presence of more severe obstructive lesions in large and small airways than the airspace pattern..3.According to HRCT lesion distribution characteristics,EGPA were divided into two pattern,and the random pattern was manifested as the signs of airway pattern.The airway obstruction and diffuse function were severe than those of peripheral zone.4.According to the HRCT classifications and chest radiography score of EGPA,it can indicate the state of illness with patients and guide further medication and treatment.