title: Pathophysiology and therapy of chronic cough.
abstract: Cough is an essential protective mechanism for the airways and lungs. Cough receptors are situated in the larynx and tracheobronchial tree, and are mediated by rapidly-adapting (irritant) Adelta fibers, although other receptors such as C-fiber receptors may contribute. Cough plasticity and interactions of cough pathways may occur centrally to enhance the cough reflex. The presence of an increased cough reflex as measured by a tussive response to capsaicin or citric acid in patients with a chronic cough indicate that there is sensitisation of the cough reflex. The most common cause of acute cough is that after a common cold, which usually lasts for less than 2 weeks. Cough that persists longer may be due to asthma and its variant forms (cough variant asthma and eosinophilic bronchitis), rhinosinusitis (postnasal drip), gastro-esophageal reflux, bronchiectasis, chronic bronchitis, and angiotensin-converting enzyme (ACE) inhibitor therapy. Chronic persistent cough can contribute to a significant worsening of quality of life measures. Bronchial tumors must be excluded with a chest radiograph. The management of chronic cough includes investigation and treatment of any associated causes, which sometimes leads to control of cough. In a proportion of patients, cough may be idiopathic and remain uncontrolled. Currently-available antitussives such as dextromethorphan or codeine are modestly successful in controlling cough. New antitussives may be developed that act on the sensory receptors or prevent their sensitisation.
authors.affiliation: Department of Respiratory Medicine, National Heart and Lung Institute, Imperial College, London, London, UK. f.chung@ic.ac.uk
authors.forename: K F
authors.initials: KF
authors.lastname: Chung
mesh_terms: D001249:Asthma / Q000150:complications; D001987:Bronchiectasis / Q000150:complications; D001991:Bronchitis / Q000150:complications; D002908:Chronic Disease; D003371:Cough / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D005100:Expectorants / Q000627:therapeutic use; D005764:Gastroesophageal Reflux / Q000150:complications; D006801:Humans; D012018:Reflex / Q000502:physiology
chemical_list: D005100:Expectorants