Cough

A cough is a sudden, often repetitive, spasmodic contraction of the thoracic cavity, resulting in violent release of air from the lungs, and usually accompanied by a distinctive sound. A cough is usually initiated to clear a buildup of phlegm in the trachea; air may move through this passage at up to 480 km/h (300 mi/h) during a contraction. Coughing can also be triggered by a bolus of food going down the trachea instead of the esophagus, due to a failure of the epiglottis, although this may result in choking instead. Frequent or chronic coughing usually indicates the presence of a disease. Provided the patient is a non-smoker and has a normal chest xray, the cause of chronic cough in 93% of all patients is due to asthma, reflux (heartburn) or post-nasal drip. Other causes of chronic cough include chronic bronchitis and medications such as ACE inhibitors.

See also

• Whooping cough
• Kennel cough
• Cough medicines, including expectorants