Global Physiology and Pathophysiology of Cough

Abstract

on behalf of the CHEST Expert Cough Panel * BACKGROUND: Cough characteristics vary between patients, and this can impact clinical diagnosis and care. The purpose of part two of this state-of-the-art review is to update the American College of Chest Physicians (CHEST) 2006 guideline on global physiology and pathophysiology of cough. STUDY DESIGN AND METHODS:A review of the literature was conducted using PubMed and MEDLINE databases from 1951 to 2019 using prespecified search terms. RESULTS:We describe the demographics of typical patients with cough in the clinical setting, including how cough characteristics change across age. We summarize the effect of common clinical conditions impacting cough mechanics and the physical properties of mucus on airway clearance.INTERPRETATION: This is the second of a two-part update to the 2006 CHEST cough guideline; it complements part one on basic phenomenology of cough by providing an extended clinical picture of cough along with the factors that alter cough mechanics and efficiency in patients. A greater understanding of the physiology and pathophysiology of cough will improve clinical management.

Cough Hypersensitivity Syndrome: Why Its Use Is Inappropriate in Children

“…Chronic cough and cough hypersensitivity is more prevalent in adult women, and this is said to be reflected in the lower threshold to elicit cough with inhaled capsaicin [16]. These findings have been found in both healthy adult women and those with chronic cough, as summarized in a recent review [16].…”

“…Cough hypersensitivity represents "increased neural responsivity to a range of stimuli affecting the airways and lungs and other tissues innervated by common nerve supplies" [15]. Clinically it presents as "excessive coughing often in response to relatively innocuous stimuli" [15] and includes allotussia, which is a cough triggered by nontussive stimuli such as smells or the eating of biscuits [16]. Cough sensitivity is measured by the concentration of the cough stimulant that triggers the number of coughs, e.g., C2 represents a concentration that stimulates two or more coughs and C5 represents a concentration that stimulates five or more coughs [17].…”

“…However, in adults, cough can be unrelenting when their primary underlying etiology cannot be identified, such as in the cases of refractory chronic cough (RCC) and unexplained chronic cough (UCC) [24]. Chronic cough and cough hypersensitivity is more prevalent in adult women, and this is said to be reflected in the lower threshold to elicit cough with inhaled capsaicin [16]. These findings have been found in both healthy adult women and those with chronic cough, as summarized in a recent review [16].…”

“…However, there are also distinct differences between children and adults. These have been summarized in a recent review [16].…”

Evaluation of smartphone-based cough data in amyotrophic lateral sclerosis as a potential predictor of functional disability

“…During the last few years, objective evaluation of cough sounds, in particular evaluating its quantitative characteristics in terms of sound frequency or intensity, has gained popularity for detecting and distinguishing different respiratory dysfunctions (12,(14)(15)(16)(17)(18). The increasing evidence concerning the objective evaluation of cough is also grounded by the physiological mechanisms of coughing which require considerable coordination and timing of breathing, thus being sensitive to abnormalities in the respiratory system (19,20). Physiologically, cough involves a deep inspiration, followed by vigorous contraction of the expiratory muscles (in particular the abdominal muscles) against a closed glottis.…”