[Etiological diagnosis of chronic cough with unknown causes]

Abstract

Objective: To explore the spectrum and frequency of causes for chronic cough in Chinese patients.

Methods: 86 patients with chronic cough were enrolled in the study. The diagnostic procedure was based on the anatomical protocol for diagnosing chronic cough designed by Irwin, and additional cytological assay was performed for sputum induced by hypertonic saline aerosol inhalation. The efficacy of therapy specific to the diagnosis was evaluated.

Results: Definite diagnosis was made in 77 (89.5%) out of the 86 patients with chronic cough. The most common causes included cough variant asthma (CVA) (24/86, 27.9%), postnasal drip syndrome (PNDs) (22/86, 25.6%), eosinophilic bronchitis (EB) (13/86, 15.1%), and gastroesophageal reflux (GER) (12/86, 14.0%). After active management based on the diagnosis, cough improved in 72 patients (93.5%).

Conclusions: In addition to CVA, PNDs and GER, eosinophilic bronchitis is also an important cause of chronic cough. A positive response to the specific therapy is essential to a definite diagnosis.