[The spectrum and clinical features of causes for chronic cough]

To explore the spectrum and clinical features of causes for chronic cough.

A total of 103 patients with at least 8 weeks of chronic cough and normal chest radiographs were recruited from the outpatient clinic of China-Japan Friendship Hospital Department of Respiratory Diseases between Oct 2005 to Feb 2009. The causes were investigated using a well established protocol according to The Chinese Respiratory Society guidelines for management of cough. The diagnostic protocol included history inquiring and physical examination, pulmonary function tests, induced sputum cell differentials, 24 h esophageal pH monitoring, CT of the paranasal sinuses or chest, fiberoptic rhinoscopy or bronchoscopy. The final diagnosis was made based on clinical manifestations, examination findings and a positive response to therapy. The results were compared with those reported in Guangzhou before.

The cause of chronic cough was defined in 95.1% of the patients, of which 83 patients (83.5%) with a single cause, 32 (13.6%) with 2 causes, and 3 (2.9%) with 3 causes. The most important causes of cough were: cough variant asthma (CVA) (n = 41, 33.3%), rhinitis and/or sinusitis (n = 30, 24.4%), gastroesophageal reflux (GERC) (n = 25, 20.3%), medicine related (n = 7, 5.7%), eosinophilic bronchitis (EB) (n = 6, 4.9%), atopic (n = 4, 3.3%), and idiopathic (n = 6, 4.9%). Other causes included pulmonary interstitial fibrosis (n = 2, 1.6%), left heart insufficiency (n = 1, 0.8%) and bronchiectasis (n = 1, 0.8%). There was more nocturnal cough in CVA (80.9%, 36/41) than in other causes (chi2 = 19.81, P<0.01). In CVA, 63.4% (26/41) was complicated with atopic rhinitis, 68.3% (28/41) showed seasonal variations, and 67.8% (19/28) aggravated in the autumn. GERC manifested more day coughs, with 56.0% (14/25) cough associated with taking food and 68.0% (17/25) with reflux symptoms. There was more productive cough in rhinitis and/or sinusitis (73.3% (22/30) ,chi2 = 24.99, P<0.01). The percentages of CVA and GERC were significantly higher than those reported in Guangzhou (chi2 value were 9.52 and 4.56 respectively, P<0.01), but those of EB and atopic cough were significantly lower (p values were 17.61 and 7.86 respectively, P<0.01).

The most common causes of chronic cough in our study were CVA, rhinitis and/or sinusitis, GERC, medicine related cough, EB and atopic cough, which were different from previous reports in other cities such as Guangzhou. The spectrum and clinical features of causes for chronic cough are important in the diagnostic procedure of chronic cough.