Towards understanding and managing chronic cough

The Clinical Approach to Chronic Cough

Chronic cough remains a significant clinical challenge, affecting approximately 10% of the population and leading to significant impairment in psychological, social, and physical quality of life. In recent years, efforts have intensified to elucidate the mechanisms underlying chronic cough and to focus on investigating and treating refractory chronic cough (RCC). A "treatable trait" approach, which focuses on identifying and addressing the specific associated causes of chronic cough, has gained traction. In some patients, RCC is likely driven by a neuropathic mechanism due to dysregulation of the neuronal pathways involved in the cough reflex, often clinically described as cough hypersensitivity syndrome. Although the initial treatment of underlying conditions remains central to managing treatable traits, the therapeutic options for RCC have expanded to include targeting cough hypersensitivity. First-line treatments now include neuromodulators and speech therapy with one P2X3 receptor antagonist (gefapixant) recently licensed in the European Union, United Kingdom, and Japan. Despite these advances, patient responses remain variable, underscoring the ongoing need for research into the pathophysiology and treatment of RCC. This article reviews current investigations and management options in treating chronic cough and RCC.

Automated Cough Analysis with Convolutional Recurrent Neural Network

Chronic cough is associated with several respiratory diseases and is a significant burden on physical, social, and psychological health. Non-invasive, real-time, continuous, and quantitative monitoring tools are highly desired to assess cough severity, the effectiveness of treatment, and monitor disease progression in clinical practice and research. There are currently limited tools to quantitatively measure spontaneous coughs in daily living settings in clinical trials and in clinical practice. In this study, we developed a machine learning model for the detection and classification of cough sounds. Mel spectrograms are utilized as a key feature representation to capture the temporal and spectral characteristics of coughs. We applied this approach to automate cough analysis using 300 h of audio recordings from cough challenge clinical studies conducted in a clinical lab setting. A number of machine learning algorithms were studied and compared, including decision tree, support vector machine, k-nearest neighbors, logistic regression, random forest, and neural network. We identified that for this dataset, the CRNN approach is the most effective method, reaching 98% accuracy in identifying individual coughs from the audio data. These findings provide insights into the strengths and limitations of various algorithms, highlighting the potential of CRNNs in analyzing complex cough patterns. This research demonstrates the potential of neural network models in fully automated cough monitoring. The approach requires validation in detecting spontaneous coughs in patients with refractory chronic cough in a real-life setting.

Exploring the concept of disease control in chronic cough

Background

Disease control in chronic diseases is an overarching concept that reflects the degree to which the goals of therapy are met. However, to date, there is no consensus on the definition of disease control in chronic cough. This study aimed to provide a conceptual exploration of patient-reported cough control in chronic cough.

Methods

This research is comprised of two subanalyses. First, patients with chronic cough receiving care at referral clinics were evaluated. Correlation analyses were performed between patient-reported cough control (a 5-point Likert scale), cough-specific patient-reported outcomes (PROs) and generic health PRO scores. Second, a survey was conducted among patients with refractory chronic cough and physicians to identify factors pertinent to cough control.

Results

The analysis of 341 patients (mean age: 55.5±15.1 years; female: 66.6%) revealed that cough control rating was moderately correlated with cough severity visual analogue scale and Leicester Cough Questionnaire scores, while demonstrating weaker correlations with cough-associated throat symptoms, cough-related complications or general health-related quality of life (QoL). In the survey of patients and physicians, both groups considered certain factors, such as cough frequency, severity and impact on QoL, to be relevant to the concept of cough control. However, patients rated "need for cough rescue drug" notably higher than physicians.

Conclusion

Patient-reported cough control was associated with cough severity or impact on QoL; however, cough control may not be fully captured by conventional cough PRO measurement tools. Further studies are warranted to define the consensus and tools to measure disease control in chronic cough.

Bronchoscopy for refractory/unexplained cough with mucus

INTRODUCTION

Refractory/unexplained cough (RUCC) is typically associated with throat symptoms and a dry cough. Some patients attending specialist cough clinics however, report sputum production (>1 tablespoon daily) and atypical sensations (urge-to-cough in chest). Bronchoscopy findings in this specific cohort have rarely been described.

AIMS

We aimed to evaluate bronchoscopy, bronchoalveolar lavage (BAL) cell differential and microbiology findings in RUCC with mucus production.

METHODS

We retrospectively reviewed case notes, procedure results and treatment of patients undergoing bronchoscopy for RUCC with more than a tablespoon of sputum daily.

RESULTS

Data were included from 54 patients with RUCC, normal or trivial findings on CT (Computerised Tomography) imaging and no response to guideline-directed treatment of their cough. Most (84%) patients had BAL neutrophilia and excessive dynamic airway collapse (EDAC) was seen in 31%. Treatment strategies in these patients differed to those adopted in typical RUCC associated with a dry cough. Management was influenced or changed in 48/54 (89%) of the patients undergoing bronchoscopy.

CONCLUSIONS

Bronchoscopy provides high diagnostic value in RUCC with mucus production (>1 tbsp daily), identifying specific treatable traits including neutrophilic airway inflammation and EDAC.

The "vicious circle" of chronic cough: the patient experience - qualitative synthesis

Aim

The aim of this study was to systematically search and synthesise findings from peer-reviewed qualitative studies describing the experiences of those living with chronic cough.

Methods

A systematic search was conducted to identify all studies that used qualitative methodology to report on the experiences of adults living with chronic cough. A thematic synthesis of the first-hand narratives was undertaken. Key themes in relation to personal perspectives and experiences of living with chronic cough were identified and grouped into analytical themes.

Results

Six studies met the inclusion criteria. The thematic synthesis generated three analytical themes: 1) "It's just a cough"; 2) "Constant cough and constant worry"; and 3) "No light at the end of the tunnel", highlighting the biopsychosocial nature of chronic cough. The synthesis highlights chronic cough as a heterogeneous experience that may appear idiosyncratic, completely consuming the lives of those living with it.

Conclusion

This is to our knowledge the first qualitative synthesis reporting on the perceptions and experiences of adults living with chronic cough. Our review draws attention to the paucity of literature that utilises qualitative methodology to explore the experience of living with chronic cough. We highlight the missing voice of people living with chronic cough in the contemporary literature. There is now a requirement for research exploring the narratives of those living with chronic cough, to gain an understanding of the condition beyond simple quantification.

The P2X3 receptor antagonist filapixant in patients with refractory chronic cough: a randomized controlled trial

BACKGROUND

P2X3 receptor antagonists seem to have a promising potential for treating patients with refractory chronic cough. In this double-blind, randomized, placebo-controlled study, we investigated the efficacy, safety, and tolerability of the novel selective P2X3 receptor antagonist filapixant (BAY1902607) in patients with refractory chronic cough.

METHODS

Following a crossover design, 23 patients with refractory chronic cough (age: 60.4 ± 9.1 years) received ascending doses of filapixant in one period (20, 80, 150, and 250 mg, twice daily, 4-days-on/3-days-off) and placebo in the other. The primary efficacy endpoint was the 24-h cough frequency on Day 4 of each dosing step. Further, subjective cough severity and health-related quality of life were assessed.

RESULTS

Filapixant at doses ≥ 80 mg significantly reduced cough frequency and severity and improved cough health-related quality of life. Reductions in 24-h cough frequency over placebo ranged from 17% (80 mg dose) to 37% (250 mg dose), reductions over baseline from 23% (80 mg) to 41% (250 mg) (placebo: 6%). Reductions in cough severity ratings on a 100-mm visual analog scale ranged from 8 mm (80 mg) to 21 mm (250 mg). No serious or severe adverse events or adverse events leading to discontinuation of treatment were reported. Taste-related adverse events occurred in 4%, 13%, 43%, and 57% of patients treated with filapixant 20, 80, 150, and 250 mg, respectively, and in 12% treated with placebo.

CONCLUSIONS

Filapixant proved to be efficacious, safe, and-apart from the occurrence of taste disturbances, especially at higher dosages-well tolerated during the short therapeutic intervention. Clinical trial registration EudraCT, eudract.ema.europa.eu, 2018-000129-29; ClinicalTrials.gov, NCT03535168.

Management and referral patterns for new-onset chronic cough in primary care patients

Background: The diagnosis and management of chronic cough in primary care is challenging despite it being one of the most common chronic conditions. Objective: Clinical characterization of patients with new-onset chronic cough in the primary care setting. Methods: This was a retrospective study of adult patients (ages ≥ 18 years) with at least three visits with primary care providers (PCP) for new-onset cough, with at least 8 weeks between the first and third visits, within a tertiary-care center and affiliated clinics between January 1, 2010, and January 1, 2019 (N = 174). We calculated the frequency of primary care visits, diagnostic testing, specialist referrals, and prescribed medications up to 18 months after the third visit with a PCP for cough. Results: Of 174 patients who met the criteria of new-onset chronic cough, >50% had four or more primary care visits related to cough. Despite that, 91 (52.3%) did not receive a referral to a specialist, and 41 (23.5%) did not receive an order for a chest radiograph during the evaluation of the chronic cough. Antibiotics and systemic corticosteroids were prescribed to 106 (61%) and 63 (36%) of the patients, respectively, and 20% were prescribed opiates. No patients were prescribed central-neuromodulating agents, and angiotensin-converting enzyme inhibitors were discontinued in 48% of the patients who were taking them (12/25). Conclusion: We found considerable heterogeneity and discrepancies with clinical guideline recommendations in patients who presented with new chronic cough. There is a substantial unmet need to study chronic cough in the primary care setting to inform important stakeholders.

Neural control of the lower airways: Role in cough and airway inflammatory disease

Airway function is under constant neurophysiological control, in order to maximize airflow and gas exchange and to protect the airways from aspiration, damage, and infection. There are multiple sensory nerve subtypes, whose disparate functions provide a wide array of sensory information into the CNS. Activation of these subtypes triggers specific reflexes, including cough and alterations in autonomic efferent control of airway smooth muscle, secretory cells, and vasculature. Importantly, every aspect of these reflex arcs can be impacted and altered by local inflammation caused by chronic lung disease such as asthma, bronchitis, and infections. Excessive and inappropriate activity in sensory and autonomic nerves within the airways is thought to contribute to the morbidity and symptoms associated with lung disease.

Long-Term Outcomes of Chronic Cough Reduction after Laparoscopic Nissen Fundoplication—A Single-Center Study

Background and Objectives: Gastroesophageal reflux disease (GERD) is one of the most common gastrointestinal diseases. It affects 20% of the adult population and is the third most common cause of chronic cough in adults. This study describes the results of LNF for the relief of GERD-related cough. Materials and Methods: The prospectively collected data on 135 laparoscopic LNF in our department from 2014 to 2018 were reviewed. During consultations, patients were asked about the frequency of symptoms using the GERD Impact Scale (GERD-IS), their satisfaction and recommendation to others, and their general condition after the procedure. Results: We analyzed 23 of 111 patients (20.7%) reporting chronic cough. The mean age was 47 years (range 27–76 years, ±13.9 years) and the mean follow-up time was 48.3 months (range 22.6–76.3 ± 18.05 months). Most patients reported relief from cough after the surgery (78.3%, p < 0.001). Five patients (22%) reported the recurrence of symptoms after a mean of 10.8 months (6–18 months). Seventeen patients (74%) would undergo the surgery again and 18 patients (78%) would recommend the surgery to their relatives. There was a statistically significant improvement in all symptoms from the GERD-IS (p < 0.05). Conclusions: LNF may play an important role in the management of GERD patients with extraesophageal symptoms. After LNF, most of the operated patients reported complete resolution of chronic cough and would recommend the procedure to their relatives.

Management of intractable chronic cough during awake craniotomy: illustrative case

BACKGROUND

Chronic cough is a common but challenging clinical condition that can adversely affect the safety of awake surgical endeavors such as awake craniotomy (AC). This case lesson highlighted a patient with severe refractory chronic cough undergoing AC for resection of a recurrent left frontal, insula, anterior temporal anaplastic ependymoma of the eloquent cortex.

OBSERVATIONS

The patient was successfully managed using a multifaceted medical treatment regimen combined with preoperative and intraoperative cough suppression therapy with a speech-language pathologist. The patient coughed only once intraoperatively and had a positive outcome.

LESSONS

Chronic cough is often multifactorial and requires a multifaceted treatment approach. Despite this challenge, select patients can successfully be navigated through AC with appropriate treatment for their condition. A review of neurogenic cough and modern treatments, which were used in this patient and would be helpful to neurologists or neurosurgeons, are also discussed.

Eliapixant (BAY 1817080), a P2X3 receptor antagonist, in refractory chronic cough: a randomised, placebo-controlled, crossover phase 2a study

BACKGROUND

ATP acting via P2X3 receptors is an important mediator of refractory chronic cough (RCC). This phase 2a double-blinded crossover study assessed the safety, tolerability and efficacy of eliapixant (BAY 1817080), a selective P2X3 receptor antagonist, in adults with RCC attending specialist centres.

METHODS

In period A, patients received placebo for 2 weeks then eliapixant 10 mg for 1 week. In period B, patients received eliapixant 50, 200 and 750 mg twice daily for 1 week per dose level. Patients were randomised 1:1 to period A-B (n=20) or B-A (n=20). The primary efficacy end-point was change in cough frequency assessed over 24 h. The primary safety end-point was frequency and severity of adverse events (AEs).

RESULTS

37 patients completed randomised therapy. Mean cough frequency fell by 17.4% versus baseline with placebo. Eliapixant reduced cough frequency at doses ≥50 mg (reduction versus placebo at 750 mg: 25% (90% CI 11.5-36.5%); p=0.002). Doses ≥50 mg also significantly reduced cough severity. AEs, mostly mild or moderate, were reported in 65% of patients with placebo and 41-49% receiving eliapixant. Cumulative rates of taste-related AEs were 3% with placebo and 5-21% with eliapixant; all were mild.

CONCLUSIONS

Selective P2X3 antagonism with eliapixant significantly reduced cough frequency and severity, confirming this as a viable therapeutic pathway for RCC. Taste-related side-effects were lower at therapeutic doses than with the less selective P2X3 antagonist gefapixant. Selective P2X3 antagonism appears to be a novel therapeutic approach for RCC.

Chronic cough caused by choledochoduodenal fistula: a case report

Background

Chronic cough is characterized by cough as the only or main symptom, with a duration of more than 8 weeks and no obvious abnormality in chest X-ray examination. Its etiology is complex, including respiratory disease, digestive system disease, circulation system disease, and psychological disease. Although a set of etiological diagnosis procedures for chronic cough have been established, it is still difficult to diagnose chronic cough and there are still some patients with misdiagnosis.

Case presentation

We present a case of a 54-year-old female patient who had chronic cough for 28 years. Physical examination had no positive signs and she denied any illness causing cough like tuberculosis, rhinitis. Recurrent clinic visits and symptomatic treatment didn’t improve the condition. Finally, gastroscopy identified the possible etiology of choledochoduodenal fistula that was proved by surgery. And after surgery, the patient's cough symptoms were significantly improved.

Conclusion

We report a rare case of chronic cough caused by choledochoduodenal fistula which demonstrates our as yet inadequate recognition of the etiology and pathogenesis. Written informed consent was obtained from the patient.

Impacts of Natural Environmental Factors and Prevalence of Airway Symptoms on the Local Spread of COVID-19: A Time-Series Analysis in Regional COVID-19 Epidemics

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is the world's largest public health concern in 2021. This study evaluated the associations of the prevalence of airway symptoms among the tested individuals and data regarding the natural environmental factors with the weekly number of newly diagnosed COVID-19 patients in Sendai City (N_t). For the derivatives of the screening test results, data from individuals with a contact history who underwent nasopharyngeal swab reverse transcription-polymerase chain reaction (RT-PCR) testing between July 2020 and April 2021 (6,156 participants, including 550 test-positive patients) were used. The value of N_t correlated with the weekly RT-PCR test-positive rate after close contact, prevalence of cough symptoms in test-positive individuals or in test-negative individuals, lower air temperature, lower air humidity, and higher wind speed. The weekly test-positive rate correlated with lower air humidity and higher wind speed. In cross-correlation analyses, natural environmental factors correlated with the regional epidemic status on a scale of months, whereas the airway symptoms among non-COVID-19 population affected on a scale of weeks. When applying an autoregression model to the serial data of N_t, large-scale movements of people were suggested to be another factor to influence the local epidemics on a scale of days. In conclusion, the prevalence of cough symptoms in the local population, lower air humidity or higher wind speed, and large-scale movements of people in the locality would jointly influence the local epidemic status of COVID-19.

Prevalence, incidence and characteristics of chronic cough among adults from the Canadian Longitudinal Study on Aging

The global prevalence of chronic cough is highly variable, ranging from 2% to 18%. There is a lack of data on the prevalence and incidence of chronic cough in the general population. The objective of this study was to investigate the prevalence and incidence of chronic cough in a sample of Canadian adults, and how these are influenced by age, sex, smoking, respiratory symptoms, medical comorbidities and lung function. Participants with chronic cough were identified from the Canadian Longitudinal Study on Aging (CLSA) based on self-reported daily cough in the past 12 months. This is a prospective, nationally generalisable, stratified random sample of adults aged 45-85 years at baseline recruited between 2011 and 2015, and followed-up 3 years later. The prevalence and incidence per 100 person-years are described, with adjustments for age, sex and smoking. Of the 30 097 participants, 29 972 completed the chronic cough question at baseline and 26 701 did so at follow-up. The prevalence of chronic cough was 15.8% at baseline and 17.6% at follow-up with 10.4-17.1% variation across seven provinces included in the CLSA comprehensive sample. Prevalence increased with age and current smoking, and was higher in males (15.2%), Caucasians (14%) and those born in North America, Europe or Oceania (14%). The incidence of chronic cough adjusted for age, sex and smoking was higher in males and in underweight and obese subjects. Subjects with respiratory symptoms, airway diseases, lower forced expiratory volume in 1 s (% predicted), cardiovascular diseases, psychological disorders, diabetes and chronic pain had a higher incidence of chronic cough. The prevalence and incidence of chronic cough is high in the CLSA sample with geographic, ethnic and gender differences, influenced by a number of medical comorbidities.

Intra-Arterial, but Not Intrathecal, Baclofen and Codeine Attenuates Cough in the Cat

Centrally-acting antitussive drugs are thought to act solely in the brainstem. However, the role of the spinal cord in the mechanism of action of these drugs is unknown. The purpose of this study was to determine if antitussive drugs act in the spinal cord to reduce the magnitude of tracheobronchial (TB) cough-related expiratory activity. Experiments were conducted in anesthetized, spontaneously breathing cats (n = 22). Electromyograms (EMG) were recorded from the parasternal (PS) and transversus abdominis (TA) or rectus abdominis muscles. Mechanical stimulation of the trachea or larynx was used to elicit TB cough. Baclofen (10 and 100 μg/kg, GABA-B receptor agonist) or codeine (30 μg/kg, opioid receptor agonist) was administered into the intrathecal (i.t.) space and also into brainstem circulation via the vertebral artery. Cumulative doses of i.t. baclofen or codeine had no effect on PS, abdominal muscle EMGs or cough number during the TB cough. Subsequent intra-arterial (i.a.) administration of baclofen or codeine significantly reduced magnitude of abdominal and PS muscles during TB cough. Furthermore, TB cough number was significantly suppressed by i.a. baclofen. The influence of these drugs on other behaviors that activate abdominal motor pathways was also assessed. The abdominal EMG response to noxious pinch of the tail was suppressed by i.t. baclofen, suggesting that the doses of baclofen that were employed were sufficient to affect spinal pathways. However, the abdominal EMG response to expiratory threshold loading was unaffected by i.t. administration of either baclofen or codeine. These results indicate that neither baclofen nor codeine suppress cough via a spinal action and support the concept that the antitussive effect of these drugs is restricted to the brainstem.

Factors and potential treatments of cough after pulmonary resection: A systematic review

Cough is a common complication following pulmonary resection. Persistent and severe cough after pulmonary resection can cause significant impairments in quality of life among postoperative patients. Complications of cough can be life-threatening. To improve patients' probability and quality of life, factors that induce cough after pulmonary resection (CAP) and potential treatments should be explored and summarized. Previous studies have identified various factors related to CAP. However, those factors have not been categorized and analyzed in a sensible manner. Here, we summarized the different factors and classified them into four groups. Potential therapies might be developed to selectively target different factors that affect CAP. However, the exact mechanism underlying CAP remains unknown, making it difficult to treat and manage CAP. In this review, we summarized the latest studies in our understanding of the factors related to CAP and potential treatments targeting those factors. This review can help understand the mechanism of CAP and develop efficient therapies and management.

Reflux-Aspiration in Chronic Lung Disease

Microaspiration, or silent aspiration, is commonly suspected in patients with refractory respiratory symptoms, including unexplained chronic cough, asthma, chronic obstructive pulmonary disease, bronchiolitis, bronchiectasis, and idiopathic pulmonary fibrosis. This suspicion is driven by the high prevalence of gastroesophageal reflux in these otherwise disparate disorders. Frequently, patients receive aggressive treatment for gastroesophageal reflux disease as a means of treating their underlying respiratory conditions, even in the absence of overt symptoms of reflux. However, clinical trials have not demonstrated a clear impact on outcomes with this strategy, and in some instances there may be potential for harm. Mechanistic studies have increasingly used gastric biomarkers obtained directly from the airways to confirm the association between reflux and respiratory disease, but results are limited by methodologic flaws and correlation. The best evidence of aspiration directly causing respiratory disorders is the histopathologic detection of foreign bodies. For most of the other chronic respiratory disorders, microaspiration may be uncommon or a secondary aggravating factor, as in patients with acute exacerbations of chronic obstructive pulmonary disease or idiopathic pulmonary fibrosis. In some cases, microaspiration is probably not a significant factor at all, such as in unexplained chronic cough. It is important to distinguish between conditions in which aspiration is primarily or directly causal and conditions in which aspiration may be indirectly aggravating, to help identify whether interventions targeting reflux and aspiration precautions should be recommended to patients. Our clinical review examines some of the evidence supporting reflux-aspiration as a mechanism for several chronic respiratory disorders and offers some management considerations when reflux-aspiration is suspected.

Identifying and Characterizing a Chronic Cough Cohort Through Electronic Health Records

BACKGROUND

Chronic cough (CC) of 8 weeks or more affects about 10% of adults and may lead to expensive treatments and reduced quality of life. Incomplete diagnostic coding complicates identifying CC in electronic health records (EHRs). Natural language processing (NLP) of EHR text could improve detection.

RESEARCH QUESTION

Can NLP be used to identify cough in EHRs, and to characterize adults and encounters with CC?

STUDY DESIGN AND METHODS

A Midwestern EHR system identified patients aged 18 to 85 years during 2005 to 2015. NLP was used to evaluate text notes, except prescriptions and instructions, for mentions of cough. Two physicians and a biostatistician reviewed 12 sets of 50 encounters each, with iterative refinements, until the positive predictive value for cough encounters exceeded 90%. NLP, International Classification of Diseases, 10th revision, or medication was used to identify cough. Three encounters spanning 56 to 120 days defined CC. Descriptive statistics summarized patients and encounters, including referrals.

RESULTS

Optimizing NLP required identifying and eliminating cough denials, instructions, and historical references. Of 235,457 cough encounters, 23% had a relevant diagnostic code or medication. Applying chronicity to cough encounters identified 23,371 patients (61% women) with CC. NLP alone identified 74% of these patients; diagnoses or medications alone identified 15%. The positive predictive value of NLP in the reviewed sample was 97%. Referrals for cough occurred for 3.0% of patients; pulmonary medicine was most common initially (64% of referrals).

LIMITATIONS

Some patients with diagnosis codes for cough, encounters at intervals greater than 4 months, or multiple acute cough episodes may have been misclassified.

INTERPRETATION

NLP successfully identified a large cohort with CC. Most patients were identified through NLP alone, rather than diagnoses or medications. NLP improved detection of patients nearly sevenfold, addressing the gap in ability to identify and characterize CC disease burden. Nearly all cases appeared to be managed in primary care. Identifying these patients is important for characterizing treatment and unmet needs.

Inhibition of viral and bacterial trigger-stimulated prostaglandin E2 by a throat lozenge containing flurbiprofen: An in vitro study using a human respiratory epithelial cell line

Objectives:

Symptoms of sore throat result from oropharyngeal inflammation, for which prostaglandin E₂ is a key mediator. Flurbiprofen is a non-steroidal anti-inflammatory that provides sore throat relief. The preliminary objective of this study was to develop an in vitro model for assessing prostaglandin E₂ stimulation by viral and bacterial triggers. The primary objective was to investigate the effect of diluted flurbiprofen-containing lozenges on prostaglandin E₂ concentrations in stimulated cells.

Methods:

Prostaglandin E₂ production was stimulated in three epithelial cell lines (A549, HEp2, and clonetics bronchial/tracheal epithelial) with influenza A virus (4.5 log₁₀ tissue culture infectious dose₅₀/mL), or bacterial lipopolysaccharide (10µ g/mL) and peptidoglycan (3µ g/mL) and incubated overnight. Prostaglandin E₂ levels were assessed by enzyme-linked immunosorbent assay up to 24 h after stimulation. The effect of flurbiprofen 8.75 mg lozenges (diluted to 0.44 mg/mL) on PGE₂ production in stimulated cells was assessed in parallel; prior to viral/LPS/PEP stimulation of cells, 300 μL of test product or control was added and incubated for 30 s, 2 and 5 min (and 10 min for bacterial trigger). Prostaglandin E₂ levels were measured following stimulation.

Results:

Viral and lipopolysaccharide/peptidoglycan infection did not consistently stimulate HEp2 cells and bronchial/tracheal epithelial cells to produce prostaglandin E₂. Influenza virus, and lipopolysaccharide/peptidoglycan stimulated high prostaglandin E₂ concentrations in A549: mean prostaglandin E₂ concentration 106.48 pg/mL with viral stimulation vs 33.82 pg/mL for uninfected cells; 83.84 pg/mL with lipopolysaccharide/peptidoglycan vs 71.96 pg/mL for uninfected cells. Flurbiprofen produced significant reductions in virus-stimulated prostaglandin E₂ vs stimulated untreated cells at 2 min (p = 0.03). Flurbiprofen produced significant reductions in lipopolysaccharide/peptidoglycan-stimulated prostaglandin E₂ concentrations from 30 s (p = 0.02), and at 2, 5 and 10 min (all p < 0.005) vs stimulated untreated cells.

Conclusions:

A549 cells provide a suitable model for assessment of prostaglandin E₂ stimulation by viral and bacterial triggers. Diluted flurbiprofen-containing lozenges demonstrated rapid anti-inflammatory activity in viral- and lipopolysaccharide/peptidoglycan-stimulated A549 cells.

Treatment of Chronic Refractory Cough in Adults: Focus on Neuromodulators and Other Therapeutic Modalities

Objective: To evaluate the literature and educate health care professionals about the different management options for chronic refractory cough (CRC). Data Sources: Searches were performed through MEDLINE (1966 to July 2020) using OVID and EBSCOhost and EMBASE (1947 to July 2020) using OVID. Search terms included chronic cough, neurogenic cough, neuromodulators, chronic cough management, and chronic cough treatment. References of all relevant articles were further used to obtain additional articles. Study Selection and Data Extraction: This review includes articles in the English language and human trial literature. Twenty-three trials explored the use of oral neuromodulators in the management of CRC. Data Synthesis: CRC is a poorly understood disease that may have a complex neuropathic etiology. Oral neuromodulators, such as amitriptyline, baclofen, gabapentin, and pregabalin, continue to be the most commonly used agents for the management of CRC. Alternative pharmacological therapies such as botulinum toxin, anesthetic agents (benzonatate, lidocaine), and narcotic agents have efficacy data, and further research into effective doses and routes of administration is warranted. Alternative nonpharmacologic therapies more commonly used included speech pathology treatment. Conclusion: Several medication and alternative treatment interventions may be effective in managing CRC. Current studies used wide dosing and titration strategies, making it challenging to standardize therapy. No consistent method of assessing cough reflex was used between studies, as well as a lack of consistent randomization and small sample sizes. Additional research is needed to standardize treatment durations, optimum doses, and place in therapy of the available interventions in the management of CRC.

Cough as an adverse effect on inhalation pharmaceutical products

Cough is an adverse effect that may hinder the delivery of drugs into the lungs. Chemical or mechanical stimulants activate the transient receptor potential in some airway afferent nerves (C-fibres or A-fibres) to trigger cough. Types of inhaler device and drug, dose, excipients and formulation characteristics, including pH, tonicity, aerosol output and particle size may trigger cough by stimulating the cough receptors. Release of inflammatory mediators may increase the sensitivity of the cough receptors to stimulants. The cough-provoking effect of aerosols is enhanced by bronchoconstriction in diseased airways and reduces drug deposition in the target pulmonary regions. In this article, we review the factors by which inhalation products may cause cough.

Obesity Predicts Treatment Response to Proton Pump Inhibitor Therapy in Patients with Chronic Cough

BACKGROUND

Chronic cough management is challenging as this condition is often associated with multiple comorbidities, requiring a multidisciplinary diagnostic approach. Little is known about the characteristics of obese patients with chronic cough. This study aims to describe treatable traits of chronic cough and the response to pump proton inhibitor (PPI) therapy in this sub-group of patients.

METHODS

A retrospective, observational study was performed in patients with chronic cough in a French University Hospital. Characteristics of chronic cough were analyzed for obese (N = 112) and non-obese (N = 355) patients. Refractory cough was estimated at 6 and 12 months.

RESULTS

The 3 main treatable traits associated with chronic cough in obese patients and non-obese patients were gastroesophageal reflux disease (GERD), asthma, and upper airway cough syndrome (UACS). A noticeable difference was the higher frequency of GERD (47.3% vs 34.6%, p = 0.0188) and obstructive sleep apnea (OSA) (9.8% vs 3.1%, p = 0.0080) in obese patients compared to non-obese patients. Pump proton inhibitor (PPI) treatment had a significantly higher success rate in obese patients (32.5% vs 17.0%, p < 0.05) and refractory cough at 12 months was less frequently reported in obese patients (22.3% vs 34.1%, p < 0.05).

CONCLUSION

In a context of chronic cough, a higher prevalence of GERD was noted in obese patients compared to non-obese patients and obese patients were more responsive to PPI treatment. Moreover, OSA was reported more frequently as a treatable trait in obese patients and should be considered early in the diagnostic evaluation. Prospective clinical studies that evaluate the contribution of obesity to chronic cough are further needed.

Change in the symptom profile treated as asthma - two cross-sectional studies twenty years apart

AIMS

The aims of the study were to investigate prevalence trends of respiratory symptoms, asthma and asthma treatment among young adults in Estonia and to estimate changes in symptom profile among subjects who self-report asthma attacks or use asthma medications.

METHODS

Two similar questionnaires on respiratory health were sent to subjects in Tartu, Estonia, aged between 20 and 44 years; first in 1993/94, and then in 2014/15. To study the impact of different respiratory symptoms on asthma diagnosis and treatment, the log-binomial regression was used to estimate the association between 'attack of asthma' (as a proxy for current asthma) and respiratory symptoms as well as asthma treatment and respiratory symptoms, adjusted for age, sex and smoking history.

RESULTS

Self-reported prevalence of asthma attack, asthma medication use and nasal allergies increased over the twenty years between studies, whereas there was no change in prevalence of asthma-related symptoms, and the prevalence of most respiratory symptoms either decreased, or remained unchanged. For women experiencing asthma attacks, the prevalence of nasal allergies increased and waking with chest tightness decreased. For men using asthma medication, the prevalence of a wheeze without a cold decreased. Women using asthma medication reported decreased prevalence of waking with chest tightness.

CONCLUSION

Self-reported asthma attacks and asthma medication use has increased in last 20 years, while the prevalence of most respiratory symptoms either decreased or did not change. It is likely that changes in asthma symptom profile have had an impact on the prevalence of asthma and asthma treatment.

Cough and airway disease: The role of ion channels

Cough is the most common reason for patients to visit a primary care physician, yet it remains an unmet medical need. It can be idiopathic in nature but can also be a troublesome symptom across chronic lung diseases such as asthma, COPD and idiopathic pulmonary fibrosis (IPF). Chronic cough affects up to 12% of the population and yet there are no safe and effective therapies. The cough reflex is regulated by vagal, sensory afferent nerves which innervate the airway. The Transient Receptor Potential (TRP) family of ion channels are expressed on sensory nerve terminals, and when activated can evoke cough. This review focuses on the role of 4 TRP channels; TRP Vannilloid 1 (TRPV1), TRP Ankyrin 1 (TRPA1), TRP Vannilloid 4 (TRPV4) and TRP Melastatin 8 (TRPM8) and the purinergic P2X3 receptor and their possible role in chronic cough. We conclude that these ion channels, given their expression profile and their role in the activation of sensory afferents and the cough reflex, may represent excellent therapeutic targets for the treatment of respiratory symptoms in chronic lung disease.