Brightling C E, Ward R, Goh K L, Wardlaw A J, Pavord I D
Department of Respiratory Medicine, Glenfield Hospital, Leicester, United Kingdom.
Am J Respir Crit Care Med. 1999 Aug;160(2):406-10. doi: 10.1164/ajrccm.160.2.9810100.
Eosinophilic bronchitis presents with chronic cough and sputum eosinophilia, but without the abnormalities of airway function seen in asthma. It is important to know how commonly eosinophilic bronchitis causes cough, since in contrast to cough in patients without sputum eosinophilia, the cough responds to inhaled corticosteroids. We investigated patients referred over a 2-yr period with chronic cough, using a well-established protocol with the addition of induced sputum in selected cases. Eosinophilic bronchitis was diagnosed if patients had no symptoms suggesting variable airflow obstruction, and had normal spirometric values, normal peak expiratory flow variability, no airway hyperresponsiveness (provocative concentration of methacholine producing a 20% decrease in FEV(1) ([PC(20)] > 8 mg/ml), and sputum eosinophilia (> 3%). Ninety-one patients with chronic cough were identified among 856 referrals. The primary diagnosis was eosinophilic bronchitis in 12 patients, rhinitis in 20, asthma in 16, post-viral-infection status in 12, and gastroesophageal reflux in seven. In a further 18 patients a diagnosis was established. The cause of chronic cough remained unexplained in six patients. In all 12 patients with eosinophilic bronchitis, the cough improved after treatment with inhaled budesonide 400 micrograms twice daily, and in eight of these patients who had a follow-up sputum analysis, the eosinophil count decreased significantly, from 16.8% to 1.6%. We conclude that eosinophilic bronchitis is a common cause of chronic cough, and that sputum induction is important in the investigation of cough.
嗜酸性粒细胞性支气管炎表现为慢性咳嗽和痰液嗜酸性粒细胞增多，但无哮喘患者出现的气道功能异常。了解嗜酸性粒细胞性支气管炎导致咳嗽的常见程度很重要，因为与无痰液嗜酸性粒细胞增多患者的咳嗽不同，这种咳嗽对吸入性糖皮质激素有反应。我们使用既定方案并在部分病例中增加诱导痰检查，对2年内转诊的慢性咳嗽患者进行了调查。如果患者没有提示可变气流受限的症状，肺功能测定值正常，呼气峰值流速变异性正常，无气道高反应性（乙酰甲胆碱激发浓度使第一秒用力呼气容积[FEV(1)]下降20%时的浓度[PC(20)]>8mg/ml），且痰液嗜酸性粒细胞增多（>3%），则诊断为嗜酸性粒细胞性支气管炎。在856例转诊患者中，共识别出91例慢性咳嗽患者。初步诊断为嗜酸性粒细胞性支气管炎的有12例，鼻炎20例，哮喘16例，病毒感染后状态12例，胃食管反流7例。另有18例患者明确了诊断。6例患者慢性咳嗽的病因仍无法解释。所有12例嗜酸性粒细胞性支气管炎患者在每日两次吸入400微克布地奈德治疗后咳嗽均有改善，其中8例进行了随访痰液分析的患者，嗜酸性粒细胞计数从16.8%显著降至1.6%。我们得出结论，嗜酸性粒细胞性支气管炎是慢性咳嗽的常见病因，诱导痰检查在咳嗽的调查中很重要。
