Chronic Cough Therapy

 

Chronic Cough Therapy

Coughing is the body’s way of keeping materials away from the trachea and lungs. Under normal circumstances the larynx and vocal folds sense when a liquid, solid, secretion or other irritant gets too close to the airway, and a brainstem reflex causes a complex coordination of the diaphragm, lungs, trachea, and laryngeal adductor (closure) muscles. The result is a sudden burst of air that expels whatever material out of the throat. The amount of irritant that is required to trigger this reflex can vary with changes in health, sensitivity, and habit.

A ‘normal’ cough reflex is essential. In fact we worry when people do not cough when they have food or liquid go the ‘wrong’ way. And certainly infections of the throat, larynx, trachea, bronchi can causes swelling, excess secretions, and increased sensitivity that can make people cough. But when coughing persists after illness, or without a logical reason, it can lead to coughing fits. This type of response is called ‘neurogenic cough’ or ‘chronic cough.’ It is characterized by being episodic, lasting for a half to a few minutes, and is non-productive (no phlegm). It also tends to increase in severity and frequency with time, and in extreme situations can result in vomiting. It is very awkward, and can cause people to avoid social situations for fear of having a coughing attack.

Research over the past 15 years has helped us to better understand the mechanism for this condition. Murray Morrison, MD in 1999 described a model by which cells in the brainstem can become more sensitive to irritant signals from on-going irritation to the larynx (Irritable Larynx Syndrome). Our work with World Trade Center responders at the Grabscheid Voice Center has shown us how an initial large irritant dose, especially with an emotional association, can start an on-going cascade of acquired laryngeal hypersensitivity. In this case, the person responds more and more strongly to lesser and lesser doses of various irritants. These irritants can be chemical, perfumes, cooking oils, cold air, cleaning agents, or even vibration of the vocal folds (talking loudly, laughing), or emotional situations.

We described this theoretical model as well as a therapy that we have found effective for reversing this acquired laryngeal hypersensitivity in the following article. The treatment is based on exposure therapy, and we have had an 80% success rate in helping people to significantly reduce their coughing severity and frequency. Those who are more likely to benefit from this treatment have an acquired hypersensitivity cough, not related to a pathology or infection, and are not on neurologic cough suppressants such as Ultram, tramadol, or nortriptyline. If these criteria are met, we find that 3-6 sessions are sufficient to provide relief.