Is laryngeal hypersensitivity the basis of unexplained or refractory chronic cough?

Abstract

BackgroundRefractory chronic cough (RCC) and unexplained chronic cough (UCC) are common problems seen in primary care and subspecialty clinics. The role of cough hypersensitivity and laryngeal dysfunction in contributing to the persistence of cough in RCC/UCC is not well recognised.MethodsData of patients with RCC and UCC evaluated in 2019 by an interdisciplinary cough clinic led by a pulmonologist and speech-language pathology team was reviewed. Patients completed validated questionnaires including the Leicester cough questionnaire (LCQ), voice handicap index (VHI) and dyspnea index questionnaire (DI) at initial encounter. Presence of cough hypersensitivity was based upon a history of allotussia and hypertussia. Laryngeal dysfunction was diagnosed in those with a history of laryngeal paresthesias, throat clearing, voice abnormalities, upper airway dyspnoea and documentation of functional or anatomic laryngeal abnormalities on nasoendoscopy.FindingsOf the 60 UCC/RCC patients analysed, 75% of patients were female and 85% were over 40 years of age. Cough hypersensitivity was documented in all patients and multiple cough triggers occurred in 75% of patients. 95%, 50% and 25% of patients reported laryngeal paresthesias, voice abnormalities and upper airway dyspnoea, respectively. Significant associations between LCQ and VHI and DI scores occurred when adjusting for age, gender, ethnicity and body mass index. Laryngeal functional abnormalities were documented on 44/60 patients on nasoendoscopy.InterpretationHypertussia, allotussia and laryngeal dysfunction are common in patients with RCC and UCC. Evaluation of UCC and RCC can delineate laryngeal hypersensitivity and allows appropriate treatment to be directed at this phenotype.

Laryngeal hypersensitivity and abnormal cough response during mannitol bronchoprovocation challenge

“…These findings are consistent with previous data. 17 Ex-smokers had less cough sensitivity compared to nonsmokers, consistent with most, but not all, previous studies. 18,19 Cough inhalation challenges have been previously performed using acidic agents (e.g., citric acid, acetic acid and tartaric acid) and other stimulants such as capsaicin.…”

The Toxicity of Wiped Dust and Airborne Microbes in Individual Classrooms Increase the Risk of Teachers’ Work-Related Symptoms: A Cross-Sectional Study

“…The majority of the 18 boar sperm toxicity-related symptoms may be due to one or more of these three mechanisms (1) mitochondrial dysfunction / oxidative stress, (2) immunological inflammation, and (3) chemosensory C-fibers. Five symptoms (headache, throat mucus and itching, shortness of breath, and cough) may be activated via all three mechanisms [99][100][101][102][103][104][105][106][107][108][109][110][111], six symptoms (stuffy and runny nose, hoarseness, sore throat, globus sensation, watery eyes) via immunological inflammation and C-fibers [99,106,[112][113][114][115][116][117][118][119], and one symptom (difficulty falling asleep) via mitochondrial dysfunction and immunological inflammation [120][121][122]. Eye discharge and increased need for sleep can be triggered due to immunological inflammation [119][120][121], and nasal stinging via C-fibers [88].…”

Cough hypersensitivity and chronic cough

“…Although sensory symptoms are present in most adults with chronic cough, <5% report no triggers or urge to cough 138 . Many patients with chronic cough, in addition to showing signs of cough hypersensitivity, also display laryngeal hypersensitivity 139 . Laryngeal hypersensitivity and dysfunction often present with chronic cough that is associated with vocal cord dysfunction, muscle tension dysphonia and globus (a sensation of a ‘lump’ in the throat (Box 3 )).…”

“…Laryngeal hypersensitivity and dysfunction represent an increased responsiveness of laryngeal protective reflexes triggered by mechanical or chemical stimuli and are considered to be part of the cough hypersensitivity syndrome. Laryngeal hypersensitivity and dysfunction are present in many patients with chronic cough and cough hypersensitivity 139 , 251 . They are often associated with comorbid post-nasal drip, rhinosinusitis, gastro-oesophageal reflux disease and asthma 252 .…”

“…Laryngeal hypersensitivity and dysfunction are present in many patients with chronic cough and cough hypersensitivity 139 , 251 . They are often associated with comorbid post-nasal drip, rhinosinusitis, gastro-oesophageal reflux disease and asthma 252 .…”