Chronic Cough in Older Adults

Chronic Cough in Older Adults Clodagh M. Ryan, MD MRCPI, Assistant Professor of Medicine, Division of Respirology, University Health Network / University of Toronto,Toronto, ON. EAR, NOSE, & THROAT DISORDERS Introduction Cough is an important physiological defense mechanism that helps clear the airway of noxious substances and excess mucus or fluid. It is defined as a forced expulsive maneuver, usually against a closed glottis, and is associated with a characteristic sound.1 For most individuals, a cough is a self-limiting event associated with a common cold and of little consequence. However, chronic cough, defined as the presence of cough lasting more than eight weeks, is troublesome and can significantly affect quality of life.2 Recent studies suggest that it is also highly prevalent (occurring in approximately 12% of the general population), and estimates of the cost of treatment derived from sales data from over-the-counter antitussives run at billions of dollars. Data from specialized cough clinics show a preponderance of females and obese patients.3 Despite perceptions of the incurable nature of an intractable cough, specialized clinics in cough have a diagnostic success rate of 90%. However, assessment and treatment of chronic cough often requires a multidisciplinary approach. Chronic coughing may occur because of hyperinnervation of the airways or because there are more triggers for coughing (e.g., elevated inflammatory mediator levels). In most individuals cough is a defensive mechanism against aspiration. However, among older adults with neuromuscular disease in whom the cough reflex is compromised, or among those with airway diseases, cough may become excessive and injurious (Table 1). These deleterious potential complications of cough can themselves cause considerable morbidity for a patient. Etiology of Cough Although the possible etiology of a chronic cough is expansive (Table 2), clinical studies have consistently shown that the majority of cases of chronic cough are attributable to three diseases in nonsmoking adults who are not using an angiotensin-converting enzyme (ACE) inhibitor: one, upper airway cough syndrome (previously known as postnasal drip syndrome); two, cough variant asthma; or three, reflux disease (Table 3).4 Patients may have one or more of these conditions simultaneously. In the community, chronic cough is most likely due to chronic smoking; however, the majority of these individuals do not seek medical attention.5 The clinical studies have evaluated a wide age range of individuals, and it is the opinion of experts that the causes of chronic cough are no different in older adults than in younger adults.6 Assessment and Management of Patients with Chronic Cough The American College of Chest Physicians, the British Thoracic Society, and the European Respiratory Society have recently published recommended diagnostic approaches to individuals with chronic cough.1,3,7 It is recommended that physicians follow one of these diagnostic algorithms and adopt a systematic approach to all patients who have chronic cough (Figure 1). Treatment and diagnostic success rates are higher with this approach. Response to treatment can be assessed with both subjective measures (cough-specific questionnaires) and objective measurements (computerized cough counting). Chronic cough is defined as a cough that persists longer than eight weeks. It is one of the most frequent complaints of patients attending physicians’ outpatient clinics. Contrary to popular belief, the diagnosis and treatment of the majority of patients can be achieved by following an empiric, integrative approach. As chronic cough may be responsible for significant deterioration in quality of life, successful management and treatment is important for individual patients. Unfortunately, failure to adequately manage chronic cough is usually due to physician ignorance of the current diagnostic algorithms, which pertain as much to older as to younger adults.