Cough reflex sensitivity after exercise challenge testing in children with asthma

Cough Hypersensitivity Syndrome: Why Its Use Is Inappropriate in Children

In children and adults, chronic cough is a common symptom presenting to health professionals worldwide. It is internationally accepted that children with chronic cough should be managed with pediatric specific management guidelines. The newly proposed clinical entity of 'cough hypersensitivity syndrome' has gained significant attention in adult literature. Given the significant differences between childhood and adult chronic cough, including in respiratory physiology and anatomy, and cough sensitivity, we address the suitability of the use of cough hypersensitivity syndrome in children. We explore these differences between childhood and adult chronic cough, explain what cough hypersensitivity is and highlight why the term cough hypersensitivity syndrome should not be used in children.

Cough and cough hypersensitivity as treatable traits of asthma

Cough is a common and troublesome symptom in people with asthma and is often associated with poorer asthma control and exacerbations. Apart from asthma, other causes or comorbidities might underlie cough in asthma, such as rhinosinusitis and bronchiectasis. Eosinophilic inflammation and bronchoconstriction can lead to an acute episode of cough or worsen chronic cough. Cough hypersensitivity with laryngeal paraesthesia, allotussia, and hypertussia might underlie the cough of asthma through augmented sensory nerve excitability of upper-airway vagal sensory nerves. Cough associated with bronchoconstriction and type 2 inflammation should respond to inhaled corticosteroids and long-acting β-adrenoceptor agonist therapy. For cough hypersensitivity in adults, speech and language therapy and neuromodulators (eg, gabapentin) could be considered. In children, there is no consistent association of asthma with cough sensitivity or between cough and asthma severity. Further research is needed to realise the potential of cough as a measure of asthma control, to understand the mechanisms of cough in asthma, and to develop safe, effective treatments and a precision-medicine approach to the management of cough in asthma in children and adults.

Effect of Capsaicin Atomization-Induced Cough on Sputum Excretion in Tracheotomized Patients After Hemorrhagic Stroke: A Randomized Controlled Trial

Background Timely and effective removal of respiratory secretions is of great significance for tracheotomized patients. The purpose of this study is to investigate the effectiveness of capsaicin nebulization to stimulate cough to promote early clearance of respiratory secretions in tracheotomized patients after hemorrhagic stroke. Method This study implemented a randomized controlled design. Sixty-three patients who were tracheotomized following a hemorrhagic stroke completed this randomized controlled trial. In the control group, 33 cases were given a routine care after tracheotomy. In the intervention group, 30 cases were given a capsaicin solution nebulization in addition to the routine care. The daily sputum output and the number of sputum suctioning were observed. The differences in sputum viscosity, cough function, and Clinical Pulmonary Infection Score (CPIS) were compared between the two groups before and after the intervention. Vital sign changes during capsaicin nebulization and suctioning were compared between the two groups in a pilot study. Results The daily sputum output of the capsaicin intervention group was significantly higher than that of the control group (p < .05). The number of sputum suctioning of capsaicin group was less than that of the control group after intervention (p < .05). The CPIS score of the capsaicin group was lower than that of the control group (p < .05) after a 1-week intervention. Patients' heart rate, respiratory rate, and oxygen saturation during capsaicin nebulization were not statistically different from those during routine sputum suctioning (p > .05). Conclusions Capsaicin atomization-induced cough can effectively promote sputum excretion of hemorrhagic stroke patients undergoing tracheotomy and has a good safety profile. The Clinical Trial registration number of this study is ChiCTR2000037772 (http://www.chictr.org.cns). Supplemental Material https://doi.org/10.23641/asha.16821352.

Desensitization of the Cough Reflex Induced by Corticosteroids in Ovalbumin-Sensitized Rabbits During Artificial Limb Exercise

Introduction

Cough is a major symptom frequently experienced during exercise, mainly in asthmatic patients. Inhaled glucocorticoids represent the keystone treatment in the management of asthma, but little is known about interactions between cough and exercise, especially in controlled patients. During exercise, cough reflex (CR) appears downregulated in healthy animal models whereas a lack of desensitization of CR has been shown in ovalbumin-sensitized animal models, mimicking asthmatic disease.

Aims and Objectives

The goal of our study was to clarify the potential modulation of the CR induced by inhaled corticosteroids (CS) in ovalbumin (OVA) sensitized rabbits during artificial limb exercise.

Materials and Methods

Seventeen OVA sensitized rabbits were studied. Among them, 9 were treated with CS delivered intravenously (OVA-Corticoids). The ventilatory response to direct tracheal stimulation, performed at rest and during exercise, was determined to assess the incidence and the sensitivity of the CR. Broncho-alveolar lavage (BAL) and cell counts were performed to determine the level of airway inflammation. Exercise was mimicked by electrically induced hindlimb muscular contractions (EMC).

Results

Compared to rest values, EMC increased minute ventilation by 28% without any decrease in respiratory resistance (Rsr). Among 322 tracheal stimulations, 172 (53%) were performed at rest and 150 (47%) during exercise. The sensitivity of CR decreased during artificial limb exercise compared to baseline in OVA-Corticoids rabbits (p = 0.0313) while it remained unchanged in OVA rabbits (p = NS).

Conclusion

Corticosteroids appear to restore the desensitization of the CR in OVA sensitized rabbits during artificial limb exercise, suggesting the potential role of airway inflammation in the pathophysiology of cough during exercise in asthmatics.