by David Bracken, MD, Director of UTMB Voice and Swallow Services
Chronic cough is a commonly encountered clinical complaint across a multitude of specialties. We are all likely to encounter it in both our professional and personal lives. It can be humbling through its impact on social isolation, economic and emotional burdens. The estimated significance within health care is estimated to result in greater than 30 million physician visits a year, and this is likely an underestimate!
The global impact of chronic cough, lasting greater than eight weeks, is thought to be around 10 percent of the global population. 1 As causative reasons are explored, clinicians should commonly reflect on pulmonary, gastric reflux mediated, sino-nasal, pharmacologic, or psychogenic causes.
Pulmonary reasons may include cough variant asthma or laryngeal irritation from inhaled corticosteroids. Gastrointestinal causes could include both acidic and non-acidic (enzymatic) reflux (making nonresponse to PPI only one hint), sino-nasal causes may span allergic rhinitis to vasomotor rhinitis in our geriatric patient populations.
One under-recognized phenomenon is that of a neurogenic source. Commonly arrived at as a diagnosis of exclusion following treatment failure to empiric therapies directed at other factors previously discussed, neurogenic cough can feel abstract and confusing in therapeutic approach. We find it may not be a matter of overabundance of triggers/stimulants but rather an “overreaction” to these stimulants.
UTMB Voice and Swallow Services provides a clinical framework for multi-disciplinary care of refractory cough under the direction of sub-specialty Laryngology specialists and Speech Language Pathologists. Our service is meant to act as collaborative partner in the co-management of your difficult cough patient. We will often continue to work with you and mobilize consultant partners across Pulmonology, Gastroenterology, or similar.
Remember, cough is a protective reflux of the critical lower respiratory tract. The reflex arc (sensation to motor) of cough involves peripheral and central nerve pathways and receptors. Changes in neurotransmission, post synaptic excitability, and nerve structure changes all play a potential role this towards pathologic sensitization phenomena.
Medical directed therapies for neurogenic cough include neuromodulator therapies. The intent of these therapies is to reduce the afferent signal intensity of laryngeal sensation, neuropathic disruption, to break the reflex arc resulting in cough to clear a perceived laryngeal irritant. Classes of medicine explored include GABA antagonists, tricyclic antidepressants, and opiate agonists.
Through monitored and guided up titration of medication strengths and therapeutic “dose discovery,” most patients can achieve 80 percent or greater reduction of cough intensity and frequency. Additionally, there are emerged procedural interventions for neurogenic chronic cough including superior laryngeal nerve blockade 2. This is a variant of regional anesthesia, in which the superior laryngeal nerve is subcutaneously anesthetized in office with a combination of lidocaine and steroid. This technique results in a near complete blockade of sensory input transiently, which in combination with our brains’ neuroplasticity, serves to “reboot” the hypervigilant and hyper-sensate sensory motor reflex arc found in laryngeal neuropathy. 3 Other procedural techniques can include injection of vocal fold fillers or even laryngeal Botox therapy.
Finally, it is important to recognize the habituation components of chronic cough. As such there is great evidence-based data towards the value of cough suppression therapy, of particular value with patients with a prodromal “tickle”-like sensation that precedes coughing fits/attacks. 4
If you have a patient with a persistent cough failing early therapies and work up consider collaborative work with Dr. David Bracken, laryngologist and director of UTMB Voice and Swallow Services. Our multidisciplinary team is there to provide comprehensive laryngeal evaluation and access to full spectrum of current advances in high quality laryngologic therapeutic interventions, and long-term interprofessional follow-up.
 | David Bracken, MD, sees patients at the UTMB Health ENT Clinic in League City. Learn more about ENT services at UTMB. |