What About That Cough?

Ralph K. Campbell, MD

Coughing has a wide range of significance and severity. Starting with the attention getting, brief cough associated with clearing the throat before speaking, progressing through what an advertisement described as "great expectorations," we can appreciate the need to look at the causes.

Another way of categorization of coughs is to consider where they originate---a superficial "tickle" from the nasopharynx or from deep down in the bronchial tree. The cough reaction is designed to clear the airway and can be initiated by just a "tickle" to the need to get copious amounts of material out of the airway. It is accomplished by a sudden, hard contraction of the diaphragm---the flat sheet of muscle that separates the chest cavity from the abdominal cavity. This increases the pressure in this closed space that, like squeezing a toothpaste tube, forces air to exit the lungs and releases the material in the airway. It will be repeated in spasms of coughing if the secretions are too sticky or viscous.

If someone is choking on a particle of food that is blocking the airway, the same action of increasing pressure in the lungs can be accomplished by the Heimlich maneuver, in which a sudden and forceful thrust in and upwards is applied just below the rib cage.

Post-nasal drip

Post-nasal drip is an apt term. Infection, irritants in the air, or nasal allergy from airborne agents such as pollens, or food allergens, can cause excessive amounts of mucus. The resulting "tickly" cough is an attempt to get this irritating stuff out of the airway.

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