Pathophysiology of Cough

Abstract

Although a cough is one of the presenting symptoms of many respiratory diseases, many patients complain of isolated cough, the causes of which cannot be identified by routine examination at the initial visit. In addition, an increasing number of patients exhibit isolated cough lasting more than 3 weeks (prolonged cough) or more than 8 weeks (chronic cough). The basic and clinical studies described here, conducted over more than 10 years and supported by the Japanese Cough Research Society, have led us to understand the causes and pathogenesis of chronic cough in Japan. Specific therapy is available for each cause of chronic cough when the cause is appropriately diagnosed. The triad of causes of chronic cough are recognized in the West to be gastroesophageal reflux-associated cough, postnasal drip-induced cough and asthma, while in Japan they consist of sinobronchial syndrome (productive cough), cough variant asthma (nonproductive cough) and atopic cough (nonproductive cough). Gastroesophageal reflux-associated cough is not common in Japan and postnasal drip-induced nonproductive cough has not been reported. One of the reasons for the discrepancy between causes in Western countries and in Japan may be the difference in diagnostic approach : anatomical in Western countries and pathophysiological in Japan.