What is the pathophysiology of neurogenic cough, and how is it evaluated and treated?
Background: Neurogenic cough is considered to be a chronic cough of more than eight weeks’ duration in the absence of typical external stimuli to the cough mechanism, making it a diagnosis of exclusion. As a result, an unusual amount of insight and understanding is required to successfully identify and treat patients with this condition.
Explore this issue:July 2015
Study design: Review of contemporary scientific literature.
Setting: Department of Otolaryngology–Head and Neck Surgery Baylor College of Medicine, Houston.
Synopsis: Neurogenic cough in isolation is often thought to be related to a type of sensory neuropathy. The strongest scientific evidence supports multiple synergistic cough inputs sensitizing the brainstem, as well as a heightened brainstem reflex. Certain symptoms lead to neurogenic etiology consideration, including onset after illness or surgery putting laryngeal nerves at risk, nonproductive cough, lack of response to antibiotics, asthma or reflux medications, dysesthesias of the larynx, and long duration of the complaint. Conversely, symptoms typical of the three most common causes of cough (gastroesophageal reflux disease, allergies and asthma, and infection) lead away from the diagnosis. Due to a hyperreflexive state, patients with neurogenic cough may be more susceptible to chemical, temperature, mechanical, or other stimulation. Cough may not occur in isolation, but rather with associated symptoms such as globus, throat pain, throat clearing, dysphagia, dysphonia, dyspnea, choking, and/or stridor. Neurogenic cough symptoms may occur in hyperfunctional airway disorders such as irritable larynx and paradoxical vocal fold motion syndromes. Treatment for neurogenic cough is aimed at symptom control. Tricyclic antidepressants, gabapentin, and pregabalin have demonstrated efficacy and are considered first-line medications, but optimal dose, length of treatment, time to maximum benefit, and relapse rates after drug cessation are unknown.
Bottom line: Because neurogenic cough is a sensory phenomenon, clinical evaluation is challenging, and it is most often a diagnosis of exclusion. Given the existing data, the first line of treatment should be based on an informative discussion with the patient.
Citation: Altman KW, Noordzij JP, Rosen CA, Cohen S, Sulica L. Neurogenic cough. Laryngoscope. 2015;125:1675-1681.
—Reviewed by Amy Hamaker