Cough is the most common presenting complaint in adults seeking medical treatment in an ambulatory setting. Chronic cough (persisting greater than 3 weeks) can be associated with myriad diseases that may overlap multiple medical specialties. For this reason, a thorough assessment of the patient with chronic cough relies on a multidisciplinary approach and close cooperation between
pulmonary medicine, gastroenterology, and otolaryngology.
In 1995, Zellwegerreported that the most common causes of persistent cough in nonsmokers, with a normal chest radiograph are postnasal drip due to chronic rhinitis or sinusitis, cough variant asthma, or gastroesophageal reflux disorder (GERD).
Postnasal drip (PND), cough-variant asthma, and gastroesophageal reflux disease (GERD) are the cause of chronic cough in 86% of adult patients. This percentage increases to over 99% when evaluating immunocompetent nonsmokers with normal chest x-ray findings and no history of ACEinhibitor use .
Differential diagnosis for cough in an adult
ACE Inhibitor medications
Pertussis (whooping cough)
Traumatic vagal injury
External auditory canal
Congestive heart failure
URI, upper-respiratory infection.
A high index of suspicion for GERD as the primary etiology of chronic cough must be maintained. It has been estimated the GERD may be clinically “silent” (ie, no heartburn) in as many as 75% of patients who are referred for chronic cough.
Clues in the patient’s history may include concomitant LPR symptoms such as throat clearing, hoarseness (especially in the morning), and globus sensation. In addition, the patient may relate worsening of the cough with substances that are
known to decrease the lower esophageal sphincter tone such as caffeine, mints, chocolate, fatty foods, cigarettes, or alcohol.
The diagnosis of LPR can be made by means of dual-channel 24-hour pH monitoring.If a patient with chronic cough is found to have signs of posterior
laryngitis, pachydermia, and/or pseudosulcuson laryngoscopy, it is reasonable to assume that reflux disease can be attributed to his/her cough. In these instances, empiric therapy with PPIs and reflux precautions are reasonable.One should be cautioned that chronic cough because of GERD is fairly slow to respond to antireflux therapy, taking 6 months or more to resolve sometimes.A great deal of patience and encouragement may be required by the treating physician.
Asthma is a respiratory disease that involves variable airflow obstruction because of inflammatory factors. The principle symptoms of asthma are shortness of breath and wheezing as a general rule, but in patients with coughvariant asthma (CVA), these cardinal signs of asthma are often absent. Most clinical criteria for establishing a diagnosis of asthma use (at least in part) spirometry (PFT) data.
Some investigators use a trial of an inhaled corticosteroid for 4 to 8 weeks to empirically treat CVA in the absence of confirmatory spirometry data. Further complicating this diagnosis of CVA is the emergence of a previously unrecognized etiology of chronic cough, referred to as “eosinophilic bronchitis,” which is characterized by airway eosinophilia without bronchial hyperresponsiveness. This condition shares similarities to CVA because both show eosinophilic sputum and improvement with inhaled corticosteroids. Obviously, the diagnosis of CVA is the purview of the treating pulmonologist, but otolaryngologists should be aware of the differing viewpoints in the diagnosis and treatment of this condition.
PND (Rhinosinusits and Allergic Rhinitis)
Unlike GERD and CVA, the association of chronic cough with upper-airway disease (allergic rhinitis/sinusitis) is imprecise and based more on empiric observations than actual scientific evidence. PND as a “cause” of cough has been advanced by clinicians who have observed that combinations of antihistamines and decongestants are often effective in the management of patients with chronic cough. In fact, rossman25 has introduced the concept of “one airway, one disease,” in which the upper and lower airways are viewed as a continuum of inflammation involving 1 airway that may have a common origin for the underlying pathological disease. Another disease process that may cause PND-associated cough is sinusitis. Holinger and Sandershave shown that sinusitis is the second most common diagnosis in children with chronic cough between the ages of 6 and 16. The actual contribution of chronic sinusitis to adult chronic cough is unknown, but clinical practice supports that it plays a role in some cases. A CT scan of the paranasal sinuses is the best test to show the presence of disease.