Research

Classification of chronic cough by systematic treatment cascade trial starting with beta agonist

Hideyasu Shimizu, Masamichi Hayashi, Yuji Saito, Yuki Mieno, Yasuo Takeuchi, Fumihiko Sasaki, Hiroki Sakakibara,Kensei Naito and Mitsushi Okazawa

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Cough 2013, 9:4 doi:10.1186/1745-9974-9-4

Published: 7 February 2013

Abstract (provisional)

Background

Chronic cough is one of the most challenging symptoms to diagnose and treat, not only because of the variety of underlying disorders but also its varying susceptibility to treatments. Etiological studies of chronic cough vary depending on the clinical settings and the particular interests of investigators.

Objectives

The purposes of this study were first to categorize the etiology of chronic cough by its response to systematic diagnostic treatments starting from the beta2 agonist and second to sub-categorize beta2 agonist responsive cough (BRC) by the airway hyperresponsiveness.

Methods

One hundred and eighty-four never-smokers received the maximal dose of procaterol to diagnose BRC. BRC was sub-categorized into two groups with or without airway hyperresponsiveness measured by the methacholine challenge test. Sinobronchial syndrome (SBS) was diagnosed by postnasal drip symptoms and by the response to clarythromycin and carbocysteine. Atopic cough (AC) was diagnosed by the evidence of atopy and the response to cetirizine hydrochloride. Gastroesophageal reflux disease (GERD) was diagnosed by the response to rabeprazole sodium. Since we did not investigate eosinophil counts in the tissue or in the induced sputum, no diagnosis of eosinophilic bronchitis was made.

Results

One hundred and nine patients had BRC. Twenty-three of them had bronchial asthma (BA), 53 had cough variant asthma (CVA) and 33 had non-hyperresponsive BRC (NHBRC). Thirty-one patients had GERD, 27 had AC and 14 had SBS. Twenty-five patients had more than one diagnosis in combination, while 6 had other miscellaneous diseases. Twelve patients were undiagnosed and 11 dropped out of the study.

Conclusions

The majority of chronic cough was BRC. NHBRC was a new chronic cough entity. GERD is a common cause of chronic cough in Japan, as in Western countries. AC and SBS are also causes of chronic cough in Japan.

Trial registration: University hospital medical information network (UMIN 000007483).

The complete article is available as a provisional PDF. The fully formatted PDF and HTML versions are in production.