Objective To investigate the etiology of chronic cough and the current status of diagnosis and treatment. Methods One hundred and twenty-five cases of chronic cough treated in the Department of Respiratory Medicine in 2005 were used for the study. Results Cough variant asthma (CVA) and postnasal drip syndrome (PNDs) were the most frequent causes of chronic cough. 52.8% of the cases were caused by diseases other than the respiratory system (cough caused by gastroesophageal reflux disease accounted for a large proportion), and 36.8% of the cases were caused by multiple overlapping causes of cough. 100% of the cases were misdiagnosed, with the longest misdiagnosis lasting up to 30 months and Complications were as high as 27.2%. After diagnosis and treatment, cough symptoms disappeared in 90.3% of patients within 1 to 2 weeks. Conclusion Chronic cough has a complex etiology, a high misdiagnosis rate, and many complications, and clinicians should pay attention to the diagnosis and treatment of chronic cough. Chronic cough is a common complaint symptom, but its complex etiology and lack of characteristic clinical manifestations can easily lead to misdiagnosis, and if it is not treated promptly and correctly, it often causes complications such as hemoptysis and cardiac arrhythmia, so the diagnosis and treatment of chronic cough is receiving increasing attention at home and abroad [1, 2]. In this paper, we clinically analyzed 125 cases of chronic cough treated in our hospital in the past year, with the aim of exploring the etiology of chronic cough and the current status of diagnosis and treatment, and improving clinicians’ understanding of chronic cough. 1. Data and methods 1.1 General data 125 patients with chronic cough, of whom 66 were male and 59 were female; aged 16-84 years, with an average age of (52±19) years, were treated in the outpatient clinic and wards of the respiratory department of our hospital from January to December 2005. 1.2 Diagnostic criteria All cases met the diagnostic criteria for chronic cough in the (draft) Guidelines for the Diagnosis and Treatment of Cough of the Respiratory Disease Branch of the Chinese Medical Association [3]. 1.3 Observation methods All cases were carefully questioned for medical history, routine blood tests, X-ray chest films, and in some cases, chest CT examinations were performed. Sputum examination, peripheral blood eosinophil assay, peripheral blood allergen assay, serum IgE assay, pulmonary function test, maximum expiratory flow (PEF) assay, fiberoptic bronchoscopy were performed in some cases according to different medical histories, and gastroscopy and nasopharyngoscopy were also done in some cases. 1.4 Statistical methods Data were expressed as mean ± standard deviation (x±s), and percentages and statistical tables were calculated, etc. 2. Results 2.1 Etiology of 125 patients with chronic cough Among the 125 cases of chronic cough, cough-variant asthma (CVA) was the most frequent, accounting for 19.2% of the cases, 14 of which were characterized by an increased dry cough at night, and four cases developed wheezing symptoms after 8 months of follow-up. Secondly, postnasal drip syndrome (PNDs) was also more frequent, accounting for 15.2% of the cases. Six of them had pre-existing allergies, and the cough was gradually controlled only after 7-10 days of treatment with antihistamines and decongestant preparations with additional glucocorticoid inhalation. In addition, five cases of misaspiration were severe coughs after drinking, three of which were post-infarction swallowing dysfunction (incomplete closure of the epiglottis), and two patients with delayed closure of the epiglottis found by nasopharyngoscopy in the pentatomic department, all of whom were over 80 years of age. The etiology of 125 patients with chronic cough was due to PNDs, gastric D esophageal reflux disease (GERD), use of angiotensin converting enzyme inhibitors (ACEI), chronic pharyngitis, aspiration, chronic heart failure, and other diseases outside the respiratory system in 66 cases (52.8%), as shown in Table 1.Table 1 Causes of 125 patients with chronic cough Note: BE: eosinophilic bronchitis; AC. Allergic cough 2.2 Chronic cough caused by multiple etiologies Among the 125 patients with chronic cough, 46 cases were caused by multiple etiologies, accounting for 36.8%. Among them, 2 etiologies coexisted in 26 cases and 3 or more etiologies coexisted in 20 cases. 2.3 Misdiagnosis of 125 cases of chronic cough All 125 patients with chronic cough had been misdiagnosed (100%), with a mean misdiagnosis time of 3 months and a maximum misdiagnosis time of 30 months. The average number of misdiagnosed hospitals was 2 and the maximum number of misdiagnosed hospitals was 8. 95% of the cases were misdiagnosed as bronchitis and chronic bronchitis. 125 patients were on multiple antibacterial drugs ranging from 10 to 62 days. 2.4 Complications in 125 patients with chronic cough 34 cases of complications occurred in 125 patients due to cough, with a complication rate of 27.2%. Among them, there were 12 cases of urinary incontinence, while women were the majority (11 cases); 10 cases of hemoptysis or blood in sputum; 6 cases of cardiac arrhythmias such as premature beats and tachycardia; and 2 cases each of insomnia, chest pain, and vomiting. 2.5 Prognosis of 125 patients with chronic cough After the diagnosis was confirmed and appropriate treatment was given, 90.3% (113 cases) of the patients’ cough symptoms disappeared within 1 to 2 weeks. Only 9.6% (12 cases) of patients had cough symptoms gradually controlled after 3-6 weeks, mainly in cases of endobronchial tuberculosis, PNDs and chronic pharyngitis. 3. Discussion Cough is an important defense mechanism of the organism, clearing airway secretions and foreign bodies and preventing the spread of respiratory infections. It is also a clinical symptom of many diseases and is one of the most common disease complaints. However, the clinical causes of cough are numerous and extensive, especially in cases of chronic cough with no obvious abnormalities on chest X-ray, which can be easily misdiagnosed. All 125 cases in our group had been misdiagnosed, and the longest misdiagnosis lasted 30 months. Most of them were misdiagnosed as bronchitis and chronic bronchitis, and a large number of antibacterial drugs were used or several tests were performed to clarify the diagnosis, which not only increased the patients’ pain but also aggravated their economic burden, so it is urgent and necessary to improve the level of diagnosis of the etiology of chronic cough by clinicians. In fact, the etiology of cough is very complex because cough receptors are not only found in the trachea and bronchi and other respiratory system sites, but also in the esophagus, paranasal sinuses, pharynx, external auditory tract, pleura, and pericardium, etc. Lesions in these systems or sites may produce cough symptoms. Our data show that causes other than the respiratory system such as PNDs, GER, ACEI, aspiration, pharyngitis, and chronic heart failure account for more than half (52.8%) of the cases, suggesting that it is necessary for every clinician to be familiar with the diagnostic process of chronic cough etiology and to broaden their diagnostic thinking. Our data showed that among the 11 causes of chronic cough, CVA was the most frequent (nearly 20%), followed by PNDs (15.2%), similar to those reported in the literature [2]. There were also five cases of chronic cough due to misaspiration, which has been poorly reported in the domestic and international literature. The causes of misaspiration are both pathological epiglottis dysfunction (cerebral infarction, etc.) and geriatric physiological epiglottis hypofunction, so with the advent of an aging society, clinicians should fully recognize and pay attention to this point. Frequent and severe coughing can seriously affect the patient’s work and life and can also cause complications in several systems throughout the body. Our data show that the complication rate of chronic cough is 27.2%. Cough leads to urinary incontinence most often, and the majority are women. There are also more coughs causing hemoptysis or sputum blood, and in order to exclude lung cancer, tuberculosis, and other diseases, chest CT examinations and fiberoptic bronchoscopy are done, which increases medical costs and prolongs the time to confirm the diagnosis. Therefore, efforts to improve clinicians’ knowledge about chronic cough are essential to shorten the time to confirm the diagnosis and reduce complications. In conclusion, cough is a common complaint of patients, but the etiology of cough, especially chronic cough, is complex. Clinicians must pay attention to the etiologic diagnosis of chronic cough, be familiar with the diagnostic process, and improve the level of diagnosis in order to effectively avoid misdiagnosis and mistreatment. Summary: With the continuous improvement of people’s living standards, the trend of high incidence of GERD in the West is also increasing year by year in China, and the danger of GERD to humans is becoming more and more common. Nowadays, many long-standing respiratory symptoms, such as asthma, intractable cough, pharyngitis, rhinitis, and otitis media must be considered as possible caused by GERD, thus reducing the chance of misdiagnosis.