Pathophysiology and clinical presentations of cough

Area of Science:

• Pulmonology
• Gastroenterology
• Pharmacology

Background:

• The human cough reflex is not fully understood but can be sensitized.
• Sensitization is a potential unifying hypothesis for chronic dry cough in various conditions.
• Common causes include rhinitis, sinusitis, postnasal drip, GERD, ACE inhibitor use, and cough-variant asthma.

Purpose of the Study:

• To explore the mechanisms of cough reflex sensitization.
• To investigate the role of inflammatory mediators and neuropeptides in chronic cough.
• To highlight the significance of cough in asthma management.

Main Methods:

• Review of existing literature on cough reflex mechanisms.
• Discussion of proposed pathways involving inflammatory mediators (e.g., bradykinin) and neuropeptides (e.g., tachykinins).
• Reference to a study using ambulatory cough recording in asthma patients.

Main Results:

• Chronic dry cough may result from sensitized cough reflex via nasal inflammation or esophageal-tracheobronchial reflexes.
• Angiotensin-converting enzyme inhibitor (ACE inhibitor) cough is linked to kinin degradation inhibition.
• Cough in asthma patients, particularly cough-variant asthma, may be underestimated and not correlate with lung function.

Conclusions:

• Cough reflex sensitization is a key mechanism in various chronic cough conditions.
• Neuropeptides like tachykinins are likely involved in cough sensitization.
• Further research into neuropeptide antagonists and the role of cough in asthma is warranted.