Does bronchial hyperresponsiveness predict a diagnosis of cough variant asthma in adults with chronic cough: a cohort study

Airway inflammation, bronchial hyperresponsiveness, and anti-asthma therapy responses in cough variant asthma and classic asthma with FEV1% ≥80% predicted

OBJECTIVE

To explore the differentiation of airway inflammation, bronchial hyperresponsiveness and anti-asthma therapy responses between the cough variant asthma (CVA) and classic asthma (CA) patients with FEV1% ≥80% predicted.

METHODS

In the first monocentre retrospective cross-sectional study, 402 patients with suspicion of CA and 544 patients with chronic cough were enrolled. Further prospective monocentre study was conducted and 66 patients of suspected asthma with negative bronchial dilation test (BDT) but positive bronchial challenge (BCT) test were enrolled and followed up for 4 weeks.

RESULTS

CA patients had higher fractional exhaled nitric oxide (FENO) values than CVA patients (36.0 ppb vs. 24.0 ppb, p < 0.0001). The predictive value of FENO for positive BCT was significantly lower in chronic cough patients compared to those with suspicion of CA (AUC = 0.603 vs. 0.728). Following four weeks anti-asthma therapy, both the CVA and CA groups showed significant improvement in both the large and small airway function and symptom relief. There was no significant difference between the respective groups. The two most valuable spirometric variables for predicting a positive response to anti-asthma treatment were the improvements of FEV1 (ΔFEV1, cut-off values = 90 ml for CA and 110 ml for CVA) and FEV1% (ΔFEV1%, cut-off values = 3.49% for CA and 2.59% for CVA) after BDT in baseline of CA and CVA patients, respectively.

CONCLUSION

Patients with CVA exhibited lower levels of airway eosinophilic inflammation compared to those with mild CA. Most patients with mild CA and CVA could benefit promptly from anti-asthma treatment. Additionally, an improvement in FEV1 and FEV1% during BDT can potentially predict positive responses to anti-asthma therapy in both groups.

Cough-Variant Asthma: A Review of Clinical Characteristics, Diagnosis, and Pathophysiology

Chronic cough is among the most common symptoms prompting medical care. Cough-variant asthma (CVA) is an asthma subset where cough is the primary symptom, without wheezing, chest tightness, or dyspnea. It is an important cause of chronic cough, estimated to account for 25% to 42% of cases, but likely underdiagnosed due to delayed recognition and pitfalls of diagnostic testing. Early recognition and treatment can reduce morbidity and delay its progression to more typical asthma. This review details the clinical characteristics, diagnosis, pathophysiology, and treatment of CVA and contrasts it with classic asthma and other causes of chronic cough.

WAO - ARIA consensus on chronic cough: Executive summary

Acute cough is a highly prevalent symptom in clinical practice. Chronic cough is a complex disease with significant impact on quality of life. The mechanistic pathways of chronic cough in cough-comorbid clinical phenotypes are elusive. Mounting evidence suggests presence of a hypersensitive cough reflex and implication of transient receptor potential channels and P2X receptors in cough neuronal pathways. Previously, the World Allergy Organization (WAO)/Allergic Rhinitis and its Impact on Asthma (ARIA) Joint Committee on Chronic Cough published updated experimental and clinical data on chronic cough, in addition to a multidisciplinary care pathway approach to its management. The goal of this manuscript is to provide clinicians with a succinct summary of chronic cough pathophysiology, clinical phenotypes, and management strategies in both primary and cough specialty care. This executive summary is a primer for clinicians on chronic cough. Increasing awareness on the topic among primary care physicians will improve the outcome of management of patients with chronic cough.

Association between clinical and pulmonary function features and diagnosis of cough variant asthma: a case-control study

OBJECTIVES

To compare physical information, such as age, sex, height, weight, body mass index (BMI) and pulmonary function test (PFT) results, between cough variant asthma (CVA) and chronic cough (CC) and establish a diagnostic model of CVA.

DESIGN

A case-control study of patients with suspected CVA enrolled at The First Affiliated Hospital of Zhejiang Chinese Medical University.

SETTING

One leader unit of the National Key Specialised Pulmonary Disease Cooperation Group in China.

PARTICIPANTS

Enrolled 545 patients who underwent PFT and bronchial provocation tests.

OUTCOME MEASURES

We obtained physical information and pulmonary test data and established the model using logistic regression analysis. The Hosmer-Lemeshow goodness-of-fit test, area under the receiver operating characteristic curve (AUC), calibration plot and decision curve analysis were used to evaluate this model. All data were analysed using SPSS V.27 and RStudio software.

RESULTS

The CVA group had more female patients (%) (68.12% vs 51.48%, p value<0.001) and lower height (m) (1.61 (0.40) vs 1.65 (3.26), p value<0.001), weight (kg) (60 (56) vs 63 (85), p value<0.001) and BMI (kg/m2) (22.59 (17.91) vs 23.28 (21.81), p value=0.016) than the CC group. Differences between CVA and CC in forced vital capacity (FVC) in percent predicted values (FVC% pred)(94.4 (57.3) vs 91.60 (94.10), p value=0.006), forced expiratory volume in 1 s/FVC (FEV1/FVC) (%) (84.65±6.82 vs 86.91±6.71, p value<0.001), peak expiratory flow in per cent predicted values (PEF% pred) (93.00 (81.10) vs 98.00 (108.00), p value=0.005), maximal mid-expiratory flow in percent predicted values (MMEF% pred) (74.50 (100.60) vs 90.85 (170.30), p value<0.001), forced expiratory flow (FEF) at 50% of FVC in per cent predicted values (FEF50% pred) (78.9(113.50) vs 93.10(169.80), p value<0.001) and FEF at 75% of FVC in per cent predicted values (FEF75% pred) (69.70 (137.60) vs 85.60 (225.80), p value<0.001) were significant. Patients with CVA were more in number compared with patients with CC at a lower degree (<65%) of MMEF% pred (32.37% vs 14.50%, p value<0.001), FEF50% pred (26.09% vs 13.02%, p value<0.001) and FEF75% pred (39.13% vs 23.67%, p value<0.001). FVC% pred, FEV1/FVC, BMI and MMEF% pred aided in establishing a model with an AUC of 0.733 (95% CI: 0.6829 to 0.7831). The model was tested using internal and external data (p value=0.2865 and p value=0.3197, respectively).

CONCLUSION

BMI, FVC% pred, FEV1/FVC (%) and MMEF% pred were used to establish the diagnostic model. Our model potentially indicates CVA.

TRIAL REGISTRATION NUMBER

NCT06199830.

The Impact of Medical Comorbidities on Cough Improvement Following Superior Laryngeal Block

INTRODUCTION

Chronic refractory cough is defined as cough lasting greater than 8 weeks and with an unclear etiology. Blockade of the internal branch superior laryngeal nerve (iSLN) has been shown to be safe and effective in the treatment of chronic cough. It remains unknown, however, if underlying comorbidities impact patient response to iSLN blockade.

METHODS

A total of 44 patients aged 18 years and older were seen at our institution's Laryngology clinics between 2019 and 2022 and treated with iSLN blockade. Patient demographics, comorbidities, and pre- and post-treatment cough severity index (CSI) scores were collected from electronic medical records. Two-tailed independent T tests were used to compare CSI scores between groups with and without 4 underlying comorbidities: GERD, pulmonary history, smoking history, and evidence of vocal fold paresis or asymmetry on stroboscopy.

RESULTS

Patients with a history of GERD or smoking and those with evidence of glottic insufficiency had similar improvements in CSI compared to those who did not (22.5 ± 26.4 vs 45.0 ± 47.1, P = .36; 32.7 ± 27.8 vs 29.0 ± 38, P = .85; 41.3 ± 18.8 vs 27.2 ± 37.7, P = .195). Patients with underlying pulmonary conditions had a significantly reduced response to iSLN blockade than did patients without underlying disease (9.85 ± 15.0 vs 47.4 ± 38.1, P = .028).

CONCLUSION

Underlying lung pathology may contribute to decreased iSLN blockade efficacy in the treatment of chronic refractory cough from laryngeal hypersensitivity and its treatment is likely necessary for optimal symptom reduction. Characterizing patient comorbidity profiles can help guide patient counseling on expected treatment efficacy.

Effect of budesonide combined with montelukast sodium on pulmonary function parameters and immunoglobulin levels in children with bronchial asthma

BACKGROUND AND AIM

Bronchial asthma is a prevalent type of respiratory disease that affects a large proportion of pediatric patients. The purpose of this study is to further investigate the clinical effects of budesonide combined with montelukast sodium in treating bronchial asthma.

METHODS

Eighty six children with bronchial asthma were equally divided into study and control groups via randomized double-blind controlled trial. The control group was treated with aerosol inhalation of budesonide combined with placebo, while the study group was treated with budesonide combined with montelukast sodium. Pulmonary function parameters, immunoglobulin, and recovery of related symptoms, along with the adverse reaction rate, were observed and compared between both groups.

RESULTS

Before treatment, there was no marked difference in pulmonary function parameters and immunoglobulin indexes between both groups (P > 0.05). All pulmonary function indicators and immunoglobulin indexes in both groups improved following therapy, with the study group outperforming the control group (P < 0.05). The recovery time of related symptoms in the study group was shorter than that in the control group (P < 0.05). The incidence of adverse reactions in both groups was compared, with notable differences (P < 0.05).

CONCLUSION

Budesonide combined with montelukast sodium in the treatment of bronchial asthma has the value of clinical application and promotion.

Methacholine and FeNO Measurement in Patients with Habit Cough

BACKGROUND

Chronic cough is one of the most common symptoms in childhood. Making a definite diagnosis is a challenge for all pediatricians especially in patients when cough is without an organic cause like in habit cough.

PATIENTS AND METHODS

In this retrospective analysis, all electronic outpatient charts of the Division of Allergology and Pneumology, between January 1, 2010 and December 31, 2019 were reviewed in order to study all children with potential habit cough. All children underwent the following diagnostic algorithms, skin prick test (SPT), measurement of fractional exhaled nitric oxide (FeNO), spirometry and methacholine challenge test (MCT). The value of a normal MCT and FeNO measurement for diagnosing habit cough was investigated.

RESULTS

The chart review revealed 482 patients with chronic cough>4 weeks. Of these, 99 (20.5%) with suspected habit cough were collected. 13 patients had to be excluded for other diagnosis and a complete data set was available in 55 patients. 33 (60.0%) of 55 patients were SPT negative and 22 (40.0%) had sensitization to common allergens. Five patients had elevated FeNO≥20 ppb and three showed severe bronchial hyperresponsiveness<0.1 mg methacholine, challenging the diagnosis of habit cough.

CONCLUSION

A normal FeNO and MCT can help confirm the clinical diagnosis of habit cough. However, in patients with positive MCT and/or elevated FeNO habit cough can be present. Especially in patients with elevated FeNO and severe BHR cough variant asthma and eosinophilic bronchitis have to be ruled out.

Therapeutic effect of modified Xiaoqinglong Decoction on cough-variant asthma and immunological functioning in children

OBJECTIVE

To investigate the effect of modified Xiaoqinglong Decoction on cough variant asthma (CVA) and immunological functioning in children.

METHODS

In this is retrospective analysis, 122 children with CAV admitted to our hospital from Mar. 2021 to Mar. 2022 were divided into an observation group (n=61) and a control group (n=61) according to treatment methods. The control group received fluticasone propionate inhalation aerosol, and the observation group additionally received Xiaoqinglong Decoction. The therapeutic efficacy in the two groups was compared after 8 weeks of treatment. The comparison indictors included scores of daytime and nighttime cough, pulmonary function, fractional exhaled nitric oxide (FeNO), eosinophil count, inflammatory response (interleukin-4 (IL-4), tumor necrosis factor-α (TNF-α) and macrophage inflammatory protein ((MIP)-1α), immunoglobulin (Ig)) level and adverse reactions.

RESULTS

The overall response rate of children with CVA in the observation group was higher than that in the control group (P<0.05). After treatment, the scores of daytime and nighttime cough in the observation group were lower than those in the control group (P<0.05). The Forced Vital Capacity (FVC), peak expiratory flow (PEF) and FEV1 (Forced Expiratory Volume)/FVC of the observation group were higher than those in the control group (P<0.05). The FeNO and eosinophil count in the observation group were lower than those in the control group (P<0.05). The serum IL-4 was higher, while TNF-α and MIP-1α levels were lower in the observation group in the control group (P<0.05). The serum IgA, IgG and IgM levels in the observation group were higher than those in the control group (P<0.05).

CONCLUSION

The modified Xiaoqinglong Decoction has a conspicuous effect on children with CVA. It helps to reduce cough symptoms, improve pulmonary function, reduce inflammatory response and improve immunological functioning of children.

Study on the Relationship Between Bronchoalveolar Lavage Fluid Cell Count, Th1/Th2 Cytokines and Pulmonary Function in Patients with Cough Variant Asthma

OBJECTIVE

This study aimed to compare lung function and airway inflammation among cough variant asthma (CVA), chronic cough and classical asthma (CA) and investigate the relationship between these indicators and their possible mechanisms of action in the progression of CVA to CA.

METHODS

36 patients with chronic cough, 39 patients with CA, and 57 patients with CVA were included in this study. Pulmonary function tests, bronchial provocation tests and FeNO tests were performed. The patients' bronchoalveolar lavage fluid (BALF) was collected, the cells in BALF were counted, and the levels of Th1 and Th2 cytokines were detected.

RESULTS

The neutrophils, lymphocytes, and eosinophils in BALF in the CA and CVA groups were significantly higher than those in the chronic cough group. Also, they were negatively correlated with FEV1, FVC, and FEV1/FVC and positively correlated with IgE and FeNO. The expression of Th2-related cytokines was increased in CVA and CA patients, and it was positively correlated with FEV1, FVC and FEV1/FVC and negatively correlated with IgE and FeNO, while the results of Th1-related cytokines were the opposite of those for Th2-related cytokines.

CONCLUSION

CVA differs from asthma and chronic cough in terms of Th1/Th2 cytokines and lung function and provides a reference for understanding the disease mechanism of early clinical progression of CVA to CA.

Inflammatory Phenotypes of Cough Variant Asthma as Response Predictors to Anti-Asthmatic Therapy

Background

Eosinophilic inflammatory phenotype was thought to be the most common phenotype of cough variant asthma (CVA), nevertheless other phenotypes were also reported.

Purpose

The study aimed to analyze the inflammatory phenotypes of CVA in relation to treatment response to the stepwise anti-asthmatic treatment.

Patients and Methods

The study included 45 patients with chronic cough (CC) and suspicion of CVA (normal chest X-ray, presence of bronchial hyperresponsiveness and no history of wheezing or dyspnea) in whom induced sputum was successfully collected. Based on the cellular composition of the sputum, patients were divided into major inflammatory phenotypes: eosinophilic, neutrophilic, paucigranulocytic or mixed granulocytic. A stepwise treatment, including inhaled corticosteroids with long-acting β₂-agonist, montelukast and short-term therapy with prednisone was initiated. Good treatment response was defined as the reduction in cough severity at least 20 mm from the baseline in visual analogue scale and improvement in cough-related quality of life assessed by the Leicester cough questionnaire at least 1.3 points after any of three steps.

Results

Finally, 40/45 (88.9%) patients improved after therapy. Eosinophilic asthma was found in 13/40 (32.5%) patients, neutrophilic in 6/40 (15.0%) and paucigranulocytic pattern in 21/40 (52.5%) patients. No one demonstrated a mixed granulocytic phenotype. The response to the treatment was similar in all groups. However, the reduction in cough severity was inversely related to the percentage of sputum neutrophils (r = −0.44, P = 0.003). We showed that the percentage of neutrophils in sputum >46% may be considered as a predictor of poor response to anti-asthmatic therapy.

Conclusion

The diversity of inflammatory phenotypes with paucigranulocytic preponderance was found in subjects with CVA. The response to anti-asthmatic treatment in patients with CVA was not related to the inflammatory phenotype. High neutrophil count in sputum may predict poor response to anti-asthmatic therapy in patients with CC and bronchial hyperresponsiveness.