Cough induced by airway vibration as a model of airway hyperreactivity in patients with acute upper respiratory tract infection

Abstract

Patients with acute upper respiratory tract infection (URTI) have been shown to be hyperreactive to inhaled tussigens such as citric acid and capsaicin, and the authors propose that this may be due to an increased sensitivity of airway receptors that mediate cough. In recent studies we have demonstrated that cough may be induced by vibration of the airway at the level of the throat or chest in patients with URTI but that the same stimuli induce little or no cough in healthy subjects. The difference between the patients with URTI and healthy subjects in their response to airway vibration may be explained on the basis of hyperreactivity of airway sensory receptors. We propose that the model of cough induced by airway vibration may be useful for studies on the pathophysiology and pharmacology of airway hyperreactivity in acute cough. The airway vibration model of cough may have some advantages over inhaled tussigens as the stimulus is easily controlled and the method is safe for use in children.

Understanding the symptoms of the common cold and influenza

“…Cough associated with URTIs is believed to be caused by a hyper-reactivity of the cough reflex that may be due to the effects of inflammatory mediators on airway sensory nerve endings. 46,47 In health, cough is readily induced by mechanical stimulation of the larynx, but when the larynx is inflamed and hyper-reactive, cough may occur spontaneously or in response to stimuli that would not normally cause cough-eg, the mildly irritating effects of cold air. Cough occurs spontaneously with an URTI, and some cough may be voluntary rather than reflex; this voluntary cough may be related to a sensation of airway irritation.…”

Nerve growth factor enhances cough and airway obstruction via TrkA receptor- and TRPV1-dependent mechanisms

“…Currently, however, most of the mechanistic information on cough is essentially derived from animal models with a normal cough reflex where a baseline-type cough is induced through the use of chemicals such as citric acid or capsaicin 4 5. Although this approach is very useful in dissecting out the airway cough receptors and those gating the cough centre, we also need to address major issues with some types of clinical cough such as the enhanced cough reflex which is seen in acute cough associated with upper respiratory tract infections (URTIs) 6. Hence, mediators involved in lowering the cough threshold and the mechanisms involved need to be studied.…”

Pathophysiology of Clinical Symptoms in Acute Viral Respiratory Tract Infections

“…The unproductive coughing may be caused by the inflammatory process spreading to the larynx since nasal inflammation causes sneezing rather than coughing. Coughing in respiratory tract infections is believed to be mediated by hyperreactivity of the cough reflex due to the effects of inflammatory mediators on the airway's sensory nerve endings (Lee et al 2002;Eccles and Lee 2004). When the larynx is inflamed and hyperreactive, coughing may occur spontaneously or in response to stimuli that would not normally cause coughing, e.g., cold air.…”