Accounting for nearly 30-40% of primary care office visits, chronic cough afflicts many of our patients. URI and asthma are certainly big players when it comes to etiology, however, there still remain a large number of patients with cough due to other etiologies.
Second to asthma, laryngopharyngeal reflux, or LPR, is likely responsible for the majority of chronic cough. Additional symptoms of LPR include throat clearing, mucus, sore throats, voice changes, dysphagia, globus(lump in the throat sensation). Another lesser known etiology for chronic cough is vagal neuropathy. Typically occurring after a virus, these patients experience a dry, chronic cough that is often preceded by a “tickle” in the throat, a “dry patch”, or a feeling of sandpaper in the throat: it is exacerbated by talking, laughing, yawning, or drinking; it can be exacerbated by smells, fumes, or changes in temperature.
Diagnosing this problem is difficult as there are few physical findings. Much akin to Bell’s palsy or acute hearing loss, this cough is caused by a chronic sensory derangement of the laryngopharyngeal tissues resulting in chronic, recurrent cough.
Chronic cough and acute/chronic hoarseness can also be caused by the use of inhaled steroids that have been prescribed at increasing frequency of the last decade. Patients will report discomfort in the throat often associated with chronic vocal changes, raspy quality, and vocal fatigue. Patients can actually develop keratosis or thickening of the vocal folds and often develop candidiasis of the oropharyngeal and laryngeal tissue.
For patients with possible LPR, symptom indices, reflux finding scores with flexible digital laryngoscopy, and pH probes of the oropharynx can be performed. FEES testing or superior laryngeal nerve blocks may be ordered if vagal neuropathy is the presumed cause. Laryngoscopy can identify fungal elements or keratotic changes. If no cause is found, CT of the sinus, skull base and neck, and chest may be required to rule out a neoplasm.
Once identified, treatment is aimed at the cause. For LPR (reflux), a diet based approach is the most important aspect of treatment; rarely medications are required, though may be used initially. Persistent symptoms may warrant further motility studies, reflux testing or esophagoscopy (done in the office with topical anesthesia). For vagal neuropathy, treatment with tricyclics or other medications for neuropathy can often provide over 85% reduction in cough frequency and severity.