Temporal associations between coughing or wheezing and acid reflux in asthmatics

Exploring objective factors to predict successful outcomes after laparoscopic Nissen fundoplication

BACKGROUND

Currently, the reported parameters that predict the resolution of symptoms after surgery are largely subjective and unreliable. Considering that fundoplication rebuilds the structural integrity of the lower esophageal sphincter (LES), the authors focused on searching for objective and quantitative predictors for the resolution of symptoms based on the anatomical issues and whether an antireflux barrier can be well established or not.

MATERIALS AND METHODS

The authors reviewed the prospectively collected data of 266 patients with gastroesophageal reflux disease (GERD) who had undergone laparoscopic Nissen fundoplication (LNF). All patients were diagnosed with GERD using preoperative esophagogastroduodenoscopy, 24-h ambulatory esophageal pH monitoring, and high-resolution esophageal manometry. The patients received GERD symptom surveys using the validated Korean Antireflux Surgery Group questionnaire twice: preoperatively and 3 months after the surgery.

RESULTS

After excluding patients with insufficient follow-up data, 152 patients were included in the analysis. Multivariate logistic regression analyses revealed that a longer length of the LES and lower BMI determined better resolution of typical symptoms after LNF (all P <0.05). Regarding atypical symptoms, higher resting pressure of LES and DeMeester score greater than or equal to 14.7 were associated with better resolution after the surgery (all P <0.05). After LNF, typical symptoms improved in 34 out of 37 patients (91.9%) with a length of LES >greater than .05 cm, BMI less than 23.67 kg/m 2 , and atypical symptoms were resolved in 16 out of 19 patients (84.2%) with resting pressure of LES greater than or equal to 19.65 mm Hg, DeMeester score greater than or equal to 14.7.

CONCLUSION

These results show that the preoperative length and resting pressure of LES is important in the objective prediction of symptom improvement after LNF.

Gastroesophageal Reflux Disease and Asthma: A Narrative Review

Gastroesophageal reflux disease (GERD) is defined by retrograde reflux of gastric contents to the esophagus leading to various signs and symptoms that range from heartburn/regurgitation to the development of extraesophageal respiratory syndromes like asthma. Although a cause-effect relationship has been proposed, evidence suggests that these two entities share a complex mechanism that may be reciprocal to each other. The understanding of the underlying mechanisms is imperial due to the fact that asthmatic patients may benefit from reflux therapy with subsequent improvement in pulmonary function testing and quality of life. This study has revised available literature in order to provide evidence for a nexus between GERD and asthma based on clinical correlation, pathophysiology, and pharmacologic management.

Reflux-related symptoms reflect poor asthma control and the presence of airway neuronal dysfunction

BACKGROUND

Gastroesophageal reflux may be associated with the worsening of asthma by increasing cough reflex sensitivity. Hull Airway Reflux Questionnaire (HARQ) consists of 14 prevalent reflux-related symptoms. It may be useful in predicting the presence of cough reflex hypersensitivity in asthma.

METHODS

From August 2018 to July 2020, 266 asthmatic patients completed the HARQ. They underwent blood analysis, spirometry, fraction of exhaled nitric oxide (FeNO) measurement, and the capsaicin cough challenge test. Patients were considered to have reflux-related symptoms if their HARQ scores were 13 points or higher. We evaluated the association between reflux-related symptoms and clinical asthma outcomes. Finally, we performed a multivariate analysis to determine the clinical significance of the HARQ for asthma. This study was registered in the University Hospital Medical Information Network (UMIN000040732).

RESULTS

The mean HARQ scores were 13.1 (standard deviation 12.0). Patients in the high HARQ scores group (HARQ ≥13, n = 105) showed a lower prevalence of atopic predisposition, lower levels of FeNO, heightened capsaicin cough reflex sensitivity, poorer asthma control, and more frequent admissions due to asthma than those in the low HARQ groups (all p values < 0.05). The HARQ was useful in selecting patients with poor controlled asthma and those with severe cough when the cut-off value was set at 13. Multivariate analysis revealed that heightened capsaicin cough reflex sensitivity affected reflux-related symptoms, as well as lower levels of FeNO and younger age.

CONCLUSIONS

Higher HARQ scores (≥13) may be useful in predicting not only poor asthma condition but also the presence of airway neuronal dysfunction in patients with asthma to some extent.

Extra-Esophageal Presentation of Gastroesophageal Reflux Disease: 2020 Update

Gastroesophageal reflux disease (GERD) is defined by the presence of symptoms induced by the reflux of the stomach contents into the esophagus. Although clinical manifestations of GERD typically involve the esophagus, extra-esophageal manifestations are widespread and less known. In this review, we discuss extra-esophageal manifestations of GERD, focusing on clinical presentations, diagnosis, and treatment. Common extra-esophageal manifestations of GERD include chronic cough, asthma, laryngitis, dental erosions, and gingivitis. Extra-esophageal involvement can be present also when classic GERD symptoms are absent, making the diagnosis more challenging. Although available clinical studies are heterogeneous and frequently of low quality, a trial with proton pump inhibitors can be suggested as a first-line diagnostic strategy in case of suspected extra-esophageal manifestations of GERD.

The Wide-Ranging Spectrum of Cough-Induced Complications and Patient Harm

Cough is one of the most common complaints encountered in every setting; however, complications associated with coughing have received relatively little attention. An exhaustive systematic review of the English literature revealed an exceedingly large and varied spectrum of cough-induced complications affecting many systems, including upper airways, chest wall and thorax, abdominal wall, heart and aorta, central nervous system, eye, gastrointestinal tract, urogenital system, and emotional and psychological harm. Prospective studies and prevalence data are conspicuously missing. Reported cough-induced pathology ranges from rare (the majority) to common and from trivial (eg, lightheadedness, subconjunctival hemorrhage) to severe and life-threatening (eg, cervical artery dissection, rupture of a normal spleen). Other seemingly benign entities may mask a serious underlying pathology (eg, cough headache, cough syncope). A substantial proportion of patients experience anxiety and insomnia, and their quality of life is affected. Thus, the wide spectrum of cough-induced pathology need to be recognized and considered in patients complaining of cough. Suppression of cough must not be neglected in patients at risk, and areas of uncertainty need to be clarified by future prospective studies.

Clinical outcomes of gastroesophageal reflux disease-related chronic cough following antireflux fundoplication

BACKGROUND

Despite the effectiveness of antireflux fundoplication for typical gastroesophageal reflux disease, outcomes regarding surgical therapy for patients with gastroesophageal reflux disease-related chronic cough are currently unclear. The purpose of this study was to evaluate whether antireflux surgery for patients with chronic cough is effective, and to assess the correlation between indexes, such as symptom index and symptom association probability, and response to surgery.

METHODS

We performed a retrospective review of a prospectively collected database from a 3-site institution from 2013 to 2017. Of 1149 patients who underwent antireflux surgery, 41 presented with chronic cough as a main symptom related to gastroesophageal reflux disease. Preoperatively, patients underwent a symptom assessment, esophagogastroduodenoscopy, esophageal 24-h pH monitoring, and manometry. Patients were followed up at 6 weeks and 12 months post-surgery.

RESULTS

Thirty-three (80.5%) patients underwent Nissen fundoplication, while 8 (19.5%) underwent Toupet fundoplication. Isolated chronic cough was present in 8 (19.5%) patients, and median (range) DeMeester score was 28.9 (0.3-96.7). After 12-month follow-up, chronic cough was absent in 28 (68.3%) patients (P = .02). Typical reflux symptoms responded well to surgery, but response was not optimal. Postoperative dysphagia and atypical reflux symptoms were slightly worse on long-term follow-up; however, differences were not significant (P ≥ .2). When examining how the different symptom indexes correlated with complete, partial, or no response in patients with gastroesophageal reflux disease-related cough, there was no notable agreement on predicted response to surgery.

CONCLUSIONS

Antireflux surgery, although less predictable, is effective for the treatment of gastroesophageal reflux disease-related chronic cough.

Review article: gastro-oesophageal reflux disease in asthma and chronic obstructive pulmonary disease

BACKGROUND

When gastro-oesophageal reflux is causing symptoms or lesions in the oesophagus, this is referred to as gastro-oesophageal reflux disease (GERD). GERD can manifest itself through typical symptoms (heartburn, regurgitation) or may lead to extra-oesophageal symptoms. Extra-oesophageal manifestations of GERD gained increasing attention over the last decade, especially respiratory disorders, because of the prevalent co-occurrence with GERD. The role of GERD in the pathogenesis of respiratory disorders has become a topic of intense discussion.

AIM

To provide an overview of the current knowledge on the role of GERD in asthma and chronic obstructive pulmonary disease (COPD).

METHODS

PubMed was searched for relevant articles using the keywords: GERD, asthma, COPD, prevalence, treatment. Case reports were excluded, only English language articles were considered.

RESULTS

Estimates for the prevalence of GERD in asthma range from 30% to 90%, compared to an average of 24% in controls. In COPD patients, the prevalence of GERD ranges from 19% to 78% compared to an average of 18% in controls. These data indicate an increased prevalence of GERD in patients with asthma and COPD, although causality is not established and GERD treatment yielded inconsistent effects. Literature supports GERD as a risk factor for COPD-exacerbations and a predictor of the 'frequent-exacerbator'-phenotype.

CONCLUSIONS

Despite the high prevalence of GERD in asthma and COPD, a causal link is lacking. The results of anti-reflux therapy on pulmonary outcome are inconsistent and contradictory. Future studies will need to identify subgroups of asthmatics and COPD patients that may benefit from anti-reflux therapy (nocturnal or silent reflux).

Diagnosis and Treatment of the Extraesophageal Manifestations of Gastroesophageal Reflux Disease

OBJECTIVE

To review the clinical presentation, diagnosis, and treatment options available for management of extraesophageal manifestations of gastroesophageal reflux disease (GERD) and to compare the most recent technological advances to the existing guidelines.

SUMMARY BACKGROUND DATA

Extraesophageal manifestations of GERD include cough, laryngopharyngeal reflux (LPR), and asthma. Recent advances in diagnostic modalities may have outpaced the existing diagnostic and therapeutic clinical guidelines.

METHODS

We searched the MEDLINE, Cochrane, and Embase databases for articles pertaining to the presentation, diagnosis, and treatment of extraesophageal manifestations of reflux, specifically cough due to reflux, LPR, and asthma due to reflux. Search terms applied to 3 thematic topics: diagnosis, medical treatment, and surgical treatment. We had searched the bibliographies of included studies, yielding a total of 271 articles for full review. We graded the level of evidence and classified recommendations by size of treatment effect, according to the guidelines from the American Heart Association Task Force on Practice Guidelines.

RESULTS

One hundred twenty-eight articles met criteria for analysis. Our findings show that the diagnosis of cough, LPR, or asthma due to gastroesophageal reflux is difficult, as no criterion standard test exits. Also, patients often present without heartburn or regurgitation typical of GERD. Combined multichannel intraluminal impedance, the pH (MII-pH) monitoring system, and the symptom association probability (SAP) test might distinguish extraesophageal manifestations of reflux from idiopathic chronic cough, laryngitis due to other causes, and atopic asthma. In addition, extraesophageal manifestations of reflux are most effectively diagnosed with a stepwise approach incorporating empiric treatment and antisecretory therapy, combined MII-pH monitoring, and surgical intervention in few selected cases.

CONCLUSIONS

Recent studies demonstrate the potential diagnostic role of MII-pH monitoring. Surgical intervention provides resolution of extraesophageal symptoms less reliably than typical symptoms when the patient has GERD.

Respiratory disease and the oesophagus: reflux, reflexes and microaspiration

Gastro-oesophageal reflux is associated with a wide range of respiratory disorders, including asthma, isolated chronic cough, idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease and cystic fibrosis. Reflux can be substantial and reach the proximal margins of the oesophagus in some individuals with specific pulmonary diseases, suggesting that this association is more than a coincidence. Proximal oesophageal reflux in particular has led to concern that microaspiration might have an important, possibly even causal, role in respiratory disease. Interestingly, reflux is not always accompanied by typical reflux symptoms, such as heartburn and/or regurgitation, leading many clinicians to empirically treat for possible gastro-oesophageal reflux. Indeed, costs associated with use of acid suppressants in pulmonary disease far outweigh those in typical GERD, despite little evidence of therapeutic benefit in clinical trials. This Review comprehensively examines the possible mechanisms that might link pulmonary disease and oesophageal reflux, highlighting the gaps in current knowledge and limitations of previous research, and helping to shed light on the frequent failure of antireflux treatments in pulmonary disease.

Symptoms of airway reflux predict exacerbations and quality of life in bronchiectasis

AIM

We have explored the association of the upper airway symptoms related to cough with exacerbation frequency, sputum microbiology and inflammatory markers in patients with non cystic fibrosis bronchiectasis.

METHODS

Patients with bronchiectasis completed the Hull Airway Reflux Questionnaire (HARQ). A score of >13 was taken to indicate the presence of reflux. Patients were followed-up with longitudinal spirometry, sputum culture and Leicester cough questionnaire (LCQ). Myeloperoxidase (MPO), free neutrophil elastase (NE) activity, Interleukin (IL)-8 and Tumour Necrosis Factor (TNF)-α was measured from spontaneous sputum samples.

RESULTS

163 completed the study. 59.5% were female. Mean age was 65.7 years. 73.6% reported airway reflux using HARQ. Patients with airway reflux had more severe cough symptoms as assessed by the LCQ [15.2 (3.5) vs. 19.4 (1.9)], p < 0.001. Sputum levels of MPO, NE, IL-8 and TNF-α were all significantly higher in the reflux positive group (p < 0.05 for all comparisons). In a multivariable logistic regression, airway reflux was independently associated with cough severity (-3.27, standard error 0.81, p = 0.0002). Airway reflux, age, FEV1 % predicted and colonization with Pseudomonas aeruginosa were independently associated with an increased risk of ≥3 bronchiectasis exacerbations in one year.

CONCLUSION

The symptoms of airway reflux independently predict severity and exacerbation frequency in non cystic fibrosis bronchiectasis.

Impact of laryngopharyngeal and gastroesophageal reflux on asthma control in children

OBJECTIVE

A prospective study was carried out to determine the sensitivity and specificity of reflux symptoms and laryngeal findings to diagnose laryngopharyngeal reflux (LPR) and gastro-esophageal reflux (GER) in children with asthma by comparing the results of double probe pH monitorization and to determine the difference between controlled and uncontrolled asthma in terms of GER and LPR coexistence.

METHODS

A total of 50 patients (23 girls, mean age 10.8±0.4 years) with mild to moderate persistent asthma were included in this study. The patients were divided in two groups according to the asthma control status as controlled (n=27) vs. uncontrolled asthma (n=23). All patients completed the reflux symptom questionnaire and then they underwent flexible fiberoptic laryngoscopy and 24h double probe (pharyngeal and esophageal) pH monitorization. Laryngopharyngeal and gastroesophageal reflux were defined according to the double probe pH meter results.

RESULTS

The prevalences of LPR and GER were 70% and 46% in asthmatic patients, respectively. The reflux symptom score and LPR disease index were not useful to predict LPR or GER. There was no association between asthma control status and LPR and GER. Vocal nodule seems to be a valuable sign to evaluate LPR in asthmatic children.

CONCLUSIONS

The reflux symptom score and LPR disease index do not seem reliable to diagnose LPR and GER in children with asthma. The frequency of LPR and GER are independent of asthma control, atopy and long acting beta agonist usage.

Capsaicin sensitivity in patients with chronic cough- results from a cross-sectional study

Background

A subgroup of patients with chronic cough is recognised as having airway symptoms resulting exposure to chemicals and scents related to enhanced cough sensitivity to inhaled capsaicin. Sensory hyperreactivity, which has an estimated prevalence of more than 6%, is one possible explanation for the symptoms experienced by these patients. We hypothesized that a number of patients diagnosed with chronic unexplained cough also have coughing provoked by chemical irritants associated with augmented capsaicin cough reaction, but the extent of such a relation is not known. One aim of the present study was to analyse cough sensitivity to inhaled capsaicin in patients with chronic unexplained cough. Another aim was to compare capsaicin sensitivity in individuals with chemically induced coughing (the chemical-sensitive group) to capsaicin sensitivity in those without such chemical sensitivity (non-sensitive group).

Methods

Fifty-six participants from an earlier cross-sectional study of 62 patients with chronic unexplained cough were asked to participate in this study: 33 were chemical-sensitive and 23 were non-sensitive. Each participant visited the clinic once and performed a capsaicin inhalation test with one of two inhalation devices. The number of coughs, induced airway symptoms, and spirometry results were recorded.

Results

Thirty-nine of the invited patients participated in the study, with 32 in the chemical-sensitive group (21 women, 11 men), and 7 in the non-sensitive group (4 women, 3 men). The chemical-sensitive patients coughed significantly more on inhaling capsaicin, and had significantly more other airway symptoms compared to those in the non-sensitive group. Women coughed significantly more than men after receiving the higher concentration of capsaicin.

Conclusions

Environmental irritants often trigger chronic unexplained cough. The current findings confirm that this sensitivity is related to enhanced capsaicin cough sensitivity and indicates more involvement of airway sensory nerves in the pathophysiology of the disease than in cough without evident trigger factors.

Gastro-oesophageal reflux in noncystic fibrosis bronchiectasis

The clinical presentation of noncystic fibrosis bronchiectasis may be complicated by concomitant conditions, including gastro-oesophageal reflux (GOR). Increased acidic GOR is principally caused by gastro-oesophageal junction incompetence and may arise from lower oesophageal sphincter hypotension, including transient relaxations, hiatus hernia, and oesophageal dysmotility. Specific pathophysiological features which are characteristic of respiratory diseases including coughing may further increase the risk of GOR in bronchiectasis. Reflux may impact on lung disease severity by two mechanisms, reflex bronchoconstriction and pulmonary microaspiration. Symptomatic and clinically silent reflux has been detected in bronchiectasis, with the prevalence of 26 to 75%. The cause and effect relationship has not been established, but preliminary reports suggest that GOR may influence the severity of bronchiectasis. Further studies examining the implications of GOR in this condition, including its effect across the disease spectrum using a combination of diagnostic tools, will clarify the clinical significance of this comorbidity.

Combined lung-sound and reflux-monitoring: a pilot study of a novel approach to detect nocturnal respiratory symptoms in gastro-oesophageal reflux disease

BACKGROUND

Increased prevalence of respiratory symptoms has been commonly reported in patients with gastro-oesophageal reflux disease (GERD).

AIM

To introduce a novel Lung-Sound-Monitoring device that allows simultaneous measurement of both nocturnal respiratory symptoms and episodes of acidic and biliary refluxes.

METHODS

Nocturnal respiratory symptoms (coughing and wheezing) were continuously recorded in 20 healthy subjects and 30 reflux patients with respiratory symptoms in parallel to combined pH-monitoring and Bilitec measurement.

RESULTS

Analysis could be completed in 20 healthy subjects and in 25 patients with reflux. A clear temporal correlation to reflux phases was detected in 49% of coughing and 41% of wheezing events, respectively. Moreover, 89% of the coughing and 100% of the wheezing events succeeded reflux episodes. Finally, the technique was capable of assessing a statistically significant difference between patients and controls regarding the occurrence of these symptoms.

CONCLUSIONS

Our pilot study establishes the Lung-Sound-Monitoring system as a unique tool to measure objectively the temporal correlation between gastroesophageal reflux and the appearance of respiratory symptoms. It represents a useful technique to identify patients with respiratory symptoms due to reflux, and therefore allows one to determine and quantify the impact of therapeutic interventions such as antireflux therapy on respiratory symptoms.

Acoustic cough-reflux associations in chronic cough: potential triggers and mechanisms

BACKGROUND & AIMS

Central sensitization is thought to play a role in chronic cough and might explain the temporal association between cough and gastroesophageal reflux (GOR) in patients in whom non-GOR causes have been excluded. Using our novel simultaneous acoustic cough recording and impedance/pH monitoring technique, we aimed to explore this further by assessing such temporal associations and their relationship to the acidity, duration, and proximal extent of reflux and the presence of erosive disease and cough reflex sensitivity in unselected patients (ie, including non-GOR causes) with chronic cough.

METHODS

Twenty-four hour ambulatory acoustic cough monitoring with simultaneous impedance/pH recording was carried out in 71 unselected patients with chronic cough, aged 51-64 years (47 female). In addition, all patients underwent cough reflex sensitivity testing to citric acid, and 66 patients underwent gastroscopy. Temporal associations between cough and reflux were expressed using the symptom association probability.

RESULTS

Seventy percent of patients exhibited temporal associations, with 48% having a positive symptom association probability (SAP(R-C)) for cough preceded by reflux (mainly distal), 56% a positive symptom association probability (SAP(C-R (2 min))) for reflux preceded by cough, and 32% both. Moreover, SAP(R-C) positive patients had a more sensitive cough reflex (P = .03) but similar esophageal reflux exposure and erosive disease, together with similar prevalence of extraesophageal causes of cough compared with SAP(R-C) negative patients. Reflux immediately following cough was rare.

CONCLUSIONS

Cough temporally associates with reflux irrespective of proposed diagnoses, may be self-perpetuating in some patients, and is likely to be driven by central processes.

Role of ATP in the ROS-mediated laryngeal airway hyperreactivity induced by laryngeal acid-pepsin insult in anesthetized rats

The pathogenetic mechanisms of laryngeal airway hyperreactivity (LAH) in patients with extraesophageal reflux are unclear. We recently reported that a laryngeal acid-pepsin insult produces LAH that is mediated through sensitization of the capsaicin-sensitive laryngeal afferent fibers by reactive oxygen species (ROS) in rats. Since ROS may promote the release of ATP from cells, we hypothesized that activation of P2X purinoceptors by ATP subsequent to an increase in ROS induces LAH in an inflamed larynx that has been insulted by acid-pepsin or H(2)O(2) (a major type of ROS). The larynxes of 208 anesthetized rats were functionally isolated while the animals breathed spontaneously. Ammonia vapor was delivered into the larynx to measure laryngeal reflex reactivity. Laryngeal insult with acid-pepsin or H(2)O(2) produced LAH with similar characteristics. The H(2)O(2)-induced LAH was prevented by laryngeal pretreatment with dimethylthiourea (a hydroxyl radical scavenger), suggesting a critical role for ROS. The LAH induced by both insults were completely prevented by ATP scavengers (a combination of apyrase and adenosine deaminase) or a P2X receptor antagonist (iso-pyridoxalphosphate-6-azophenyl-2',5'-disulfonate). Laryngeal application of a P2X receptor agonist (alpha,beta-methylene-ATP) also produced LAH. An insult with either acid-pepsin or H(2)O(2) similarly promoted an increase in the levels of ATP, lipid peroxidation, and inflammation in the larynx. Our findings suggest that laryngeal insult with acid-pepsin or H(2)O(2) induces inflammation and produces excess ROS in the rat's larynx. The latter may in turn promote the release of ATP to activate P2X receptors, resulting in sensitization of capsaicin-sensitive laryngeal afferent fibers and LAH.

Obstructive sleep apnea syndrome and asthma: what are the links?

Recent data suggest that obstructive sleep apnea syndrome (OSAS) is an independent risk factor for asthma exacerbations. Neuromechanical reflex bronchoconstriction, gastroesophageal reflux, inflammation (local and systemic), and the indirect effect on dyspnea of OSAS-induced cardiac dysfunction have been suggested as mechanisms that lead to worsening asthma control in patients with concomitant OSAS. Vascular endothelial growth factor-induced airway angiogenesis, leptin-related airway changes, and OSAS-induced weight gain also may play a common mechanistic role linking both disorders. Several studies have confirmed that asthmatic patients are more prone to develop OSAS symptoms than are members of the general population. The common asthmatic features that promote OSAS symptoms are nasal obstruction, a decrease in pharyngeal cross sectional area, and an increase in upper airway collapsibility. Clarifying the nature of the relationship between OSAS and asthma is a critical area with important therapeutic implications.

Systematic review: the extra-oesophageal symptoms of gastro-oesophageal reflux disease in children

BACKGROUND

Extra-oesophageal symptoms are thought to be common, atypical symptoms of gastro-oesophageal reflux disease (GERD) in children.

AIM

To investigate the prevalence of GERD in children with extra-oesophageal symptoms or of extra-oesophageal symptoms in children with GERD, and the effect of GERD therapies on extra-oesophageal symptoms.

METHODS

A systematic review of articles in PubMed and EMBASE.

RESULTS

We identified 18 relevant articles. The pooled weighted average prevalence of GERD in asthmatic children was 23%, compared with 4% in healthy controls from the same five studies. The majority of studies evaluating the relationship between apparent life-threatening event (ALTE) and GERD did not suggest a causal relationship. Seven studies reported that respiratory symptoms, sinusitis and dental erosion were significantly more prevalent in children with GERD than in controls. Data from pharmacotherapeutic trials were inconclusive and provided no support for a causal relationship between GERD and extra-oesophageal symptoms.

CONCLUSIONS

Possible associations exist between GERD and asthma, pneumonia, bronchiectasis, ALTE, laryngotracheitis, sinusitis and dental erosion, but causality or temporal association were not established. Moreover, the paucity of studies, small sample sizes and varying disease definitions did not allow firm conclusions to be drawn. Most trials of GERD therapies showed no improvement in extra-oesophageal symptoms in children.

High prevalence of gastroesophageal reflux symptoms in patients with both acute and nonacute cough

Although there have been many studies that showed a close association between gastroesophageal reflux disease (GERD) symptoms and chronic cough, it has been unknown whether acute cough is also associated with GERD. The aim of this study was to evaluate the relationship between GERD and respiratory symptoms in general practice. 1725 consecutive patients who first attended our hospital were enrolled in the present study. They were asked to respond the F-scale questionnaire regardless of their chief complaints. Over all, 656 (38%) patients were diagnosed as GERD and 226 (13%) had respiratory symptoms. Patients with respiratory symptoms had GERD symptoms more frequently than patients without respiratory symptoms (p < 0.05). Forty-three (37%) of 115 patients with acute cough and 48 (43%) of 111 with nonacute cough had GERD symptoms, suggesting that development of GERD is not associated with the period of respiratory symptoms. Patients with respiratory symptoms are at a significantly increased risk of developing GERD. Whether or not treatment for GERD or respiratory diseases is useful for the prevention of respiratory symptoms and GERD, respectively, should not be driving management decisions in primary care.

Airway acidification and gastroesophageal reflux

Although challenging to study, researchers recently recognized the relevance of airway pH to the pathophysiology of several respiratory diseases, ranging from asthma and cystic fibrosis to pneumonia. The airway epithelium is extraordinarily sensitive to acid. Gastroesophageal reflux can and does cause respiratory symptoms, through both neurally mediated pathways and direct aspiration. Direct aspiration has a variety of immunologic, biochemical, and physiologic effects that aggravate asthma and other respiratory diseases, yet strategies to diagnose and treat gastroesophageal reflux-related respiratory symptoms remain imprecise.

Review article: respiratory manifestations of gastro-oesophageal reflux disease

BACKGROUND

Respiratory manifestations represent one of the most prevalent and difficult-to-manage extra-oesophageal syndromes of gastro-oesophageal reflux disease.

AIMS

To review the epidemiology, pathophysiological mechanisms and therapeutic outcomes of reflux-related respiratory disorders.

METHODS

Search of the literature published in English using PubMed database.

RESULTS

There is a discrepancy between the high prevalence of reflux in asthmatics and the limited efficacy of antireflux therapies. Asthma per se may cause reflux. Patients with difficult-to-treat asthma and/or nocturnal symptoms should be screened for reflux. Reflux can induce chronic cough through different mechanisms including micro-aspiration and both local and central reflexes. Cough and reflux may precipitate each other. A meta-analysis found no significant difference between placebo and proton pump inhibitors in the resolution of cough. Encouraging results have been reported, following antireflux surgery in patients selected on the basis of pH-impedance monitoring. Attention has been drawn to obstructive sleep apnoea syndrome.

CONCLUSIONS

The role of gastro-oesophageal reflux disease in the pathogenesis of miscellaneous respiratory disorders has been discussed for decades and established in asthma and cough. However, no major therapeutic advances have been reported recently. Future trials should concentrate on patient selection and the control of efficacy using recently developed technologies, such as pH-impedance monitoring.

Method and apparatus for intra-esophageal cough detection

Gastro-esophageal reflux disease (GERD) is a common cause of chronic cough. However, a low-cost diagnostic tool for linking GERD and cough in a cause and effect relationship is still lacking. In the present study, an intra-esophageal cough detection probe that comprises a miniature white-light interferometric fiber optic pressure sensor is proposed. This innovative catheter provides a custom encapsulation of the pressure sensor which specifically optimizes the sensitivity to pressure responses triggered by cough events. In vitro and in vivo testing results of the initial cough detection probe are presented. Experimental results demonstrated the feasibility of using the proposed catheter for identifying cough episodes. The presented work can be integrated with commercial reflux pH/impedance probes to facilitate simultaneous 24-hour ambulatory monitoring of cough and reflux events, with the ultimate goal of quantifying the temporal correlation between the two types of events.

Environmental factors in the etiology of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is currently one of the most common health problems in the Western world, affecting up to 20% of the adult population weekly and 50% monthly. It generates substantial suffering among patients as well as significant costs to both patients and society in general. GERD can further result in serious complications such as esophageal strictures, Barrett's esophagus and esophageal adenocarcinoma. This review discusses the current knowledge on risk factors and potential protective factors in the development of GERD.

The association between gastro-oesophageal reflux disease and asthma: a systematic review

BACKGROUND AND AIMS

Gastro-oesophageal reflux disease (GORD) has been linked to a number of extra-esophageal symptoms and disorders, primarily in the respiratory tract. This systematic review aimed to provide an estimate of the strength and direction of the association between GORD and asthma.

METHODS

Studies that assessed the prevalence or incidence of GORD in individuals with asthma, or of asthma in individuals with GORD, were identified in Medline and EMBASE via a systematic search strategy.

RESULTS

Twenty-eight studies met the selection criteria. The sample size weighted average prevalence of GORD symptoms in asthma patients was 59.2%, whereas in controls it was 38.1%. In patients with asthma, the average prevalence of abnormal oesophageal pH, oesophagitis and hiatal hernia was 50.9%, 37.3% and 51.2%, respectively. The average prevalence of asthma in individuals with GORD was 4.6%, whereas in controls it was 3.9%. Pooling the odds ratios gave an overall ratio of 5.5 (95% CI 1.9-15.8) for studies reporting the prevalence of GORD symptoms in individuals with asthma, and 2.3 (95% CI 1.8-2.8) for those studies measuring the prevalence of asthma in GORD. One longitudinal study showed a significant association between a diagnosis of asthma and a subsequent diagnosis of GORD (relative risk 1.5; 95% CI 1.2-1.8), whereas the two studies that assessed whether GORD precedes asthma gave inconsistent results. The severity-response relationship was examined in only nine studies, with inconsistent findings.

CONCLUSIONS

This systematic review indicates that there is a significant association between GORD and asthma, but a paucity of data on the direction of causality.

Omeprazole reduces the response to capsaicin but not to methacholine in asthmatic patients with proximal reflux

OBJECTIVE

To study the relationships between airway responsiveness to methacholine and capsaicin, proximal or distal reflux and the effects of short-term acid inhibition.

MATERIAL AND METHODS

Twenty-nine asthmatics, not taking steroids regularly, underwent respiratory symptom measurements, 24-h dual-probe pH monitoring, and challenges with methacholine and capsaicin. Challenges and symptom measurements were repeated after 12 days' omeprazole treatment (20 mg b.i.d.). The results (median and range) were expressed as PD20 methacholine (mg) and PD5 capsaicin (dose causing five coughs, nmol).

RESULTS

Seventeen patients presented pathological reflux in the distal esophagus, and 17 in the proximal esophagus. At baseline no correlation was found between PD20 or PD5 and reflux. Treatment with omeprazole did not change bronchial responsiveness to methacholine (basal: 0.16 mg, 0.02-1.27; omeprazole: 0.15 mg, 0.02-1.60); omeprazole decreased the tussive response to capsaicin (basal: 0.08 nmol, 0.08-2.46; omeprazole: 0.61 nmol, 0.08-9.84, p<0.001) only in patients with pathological reflux. The decrease was positively correlated with proximal acid exposure (r2=0.70, p<0.001). Omeprazole reduced asthma symptoms in patients with proximal reflux, cough in those with proximal or distal reflux.

CONCLUSIONS

In asthmatics, inhibition of gastric acid secretion does not influence bronchial hyperresponsiveness but decreases tussive sensitivity and this effect is related to proximal reflux.

Technology review: Esophageal impedance monitoring

Intraluminal impedance monitoring is a new technique that can be used to detect the flow of liquids and gas through hollow viscera. In combination with manometry, it is used for esophageal function testing and while manometry provides information on contractile activity, impedance provides information on esophageal bolus transit. This is especially useful in patients with nonobstructive dysphagia. However, impedance monitoring appears to be less suitable for the evaluation of patients with achalasia. When used in combination with esophageal pH monitoring, impedance monitoring makes gastroesophageal reflux monitoring more complete because it allows recognition of both acidic and weakly acidic reflux episodes. The results of several studies suggest that impedance-pH monitoring is useful in the evaluation of patients with PPI-resistant typical reflux symptoms, chronic unexplained cough, excessive belching, and rumination.

Airway acidification: interactions with nitrogen oxides and airway inflammation

Airway acidification is increasingly appreciated to occur in inflammatory obstructive airway diseases, resulting from acid reflux and aspiration and from direct acid formation in the airways. Acidity activates oxidants and nitrogen oxides to create a potent antimicrobial environment. Neurogenic inflammation is triggered by airway or esophageal acidification, innate immune cells are affected by acidity, and there are pathways by which the acquired immune system also can be activated by the chemistry of an acidic airway. Measuring airway acidity is now readily achievable with noninvasive breath assays, a procedure that has opened a window on the need to understand airway pH homeostasis in health and pH dysregulation in disease.

Measurement of cough

Cough is one of the most common symptoms encountered by clinicians particularly when it is persistent. Assessment of cough is essential for determining treatment outcomes, testing new therapies and for study of pathophysiology and mechanisms. There are new tools for measuring different aspects of cough. Apart from the patient's subjective assessment of cough severity using clinical scores, the impact of cough on quality of life can be measured. Direct measurement of cough counts is now possible by using portable devices, but how the counts relate to severity is unclear. A measure of cough intensity is required. Cough reflex measured by response to inhaling citric acid or capsaicin provides a measure of cough sensitivity that may be related to cough severity. In many intervention studies of cough, the response has usually been measured in terms of physician assessment of cough and its changes in cough reflex. How the information obtained between these different measurements interrelate needs to be determined.

The relation between gastroesophageal reflux and respiratory symptoms in a population-based study: the Nord-Trøndelag health survey

BACKGROUND

In spite of numerous investigations, the relation between respiratory symptoms and reflux symptoms in the general population remains unclear, since population-based studies are few.

STUDY OBJECTIVES

To investigate the relation between respiratory symptoms and reflux symptoms in the population.

SUBJECT AND METHODS

In a cohort of 65,363 individuals representing 71.2% of the adult population in the Norwegian county of Nord-Trøndelag, 58,596 individuals (89.6%) responded to questions concerning reflux symptoms. The 3,153 persons (5.4%) with severe and recurrent reflux symptoms constituted the case group, and the 40,210 persons (68.6%) without reflux symptoms served as the control group. Odds ratios (ORs) with 95% confidence intervals (CIs) represented relative risks. Potential confounding was tested in multivariable logistic regression analysis.

RESULTS

Persons with asthma had reflux to a 60% greater extent than those without asthma after including adjustment for asthma medication (OR, 1.6; 95% CI, 1.4 to 1.9). There was a statistically significant dose-response association between breathlessness and reflux symptoms (p for trend < 0.0001), and the OR of severe breathlessness was 12.0 (95% CI, 9.5 to 15.2). Persons with heavy and wheezy breathing, daily cough, daily productive cough, or chronic cough showed a twofold to threefold statistically significant increase in risk of reflux symptoms. Adjustment for asthma or use of asthma medication did not substantially influence the risk estimates for any of the studied respiratory disorders.

CONCLUSIONS

Reflux symptoms commonly coexist with asthma and other respiratory symptoms on a population-based level, seemingly irrespective of asthma medication.

Identification of acid reflux cough using serial assays of exhaled breath condensate pH

Background

Chronic cough is a common problem, frequently caused or exacerbated by acid reflux. Diagnosis of acid reflux cough is haphazard currently, often relying on long therapeutic trials of expensive medications. We tested the hypothesis that the most relevant mechanistic component of acid reflux in chronic cough is when it rises to the level of the airway where acid can potentially be aspirated. We further wished to determine if multi-sample exhaled breath condensate (EBC) pH profiles can identify chronic cough patients likely to respond to proton pump inhibitor therapy.

Methods

59 subjects were recruited for this study. Initially we examined EBC pH (gas-standardized with Argon) in the setting of 15 experimental pharyngeal acid challenges to determine duration of EBC acidification. Subsequently, we enrolled 22 healthy subjects to determine a normal multi-sample exhaled breath condensate pH profile over 1–3 days. We additionally obtained multi-sample EBC pH profiles in 22 patients with chronic cough. These samples were timed to occur after coughing episodes. Exhaled breath condensate pH was measured after gas standardization.

Results

We found that exhaled breath condensate pH is substantially reduced for approximately 15 minutes after pharyngeal acid load. Healthy subjects rarely have any low EBC pH values (defined as < 7.4 based on a normative reference range from 404 healthy subjects). Patients with chronic cough who subsequently responded well to proton pump inhibition (n = 8) invariably had one or more cough episodes associated with EBC acidification. No patient who had normal EBC pH with each of their cough episodes reported a clinically relevant response to proton-pump inhibition.

Conclusion

Patients whose cough responds to proton pump inhibition have transient exhaled breath condensate acidification with coughing episodes, supporting the role of airway acidification in reflux-triggered cough. Multi-sample EBC pH profiles, involving samples collected immediately subsequent to a coughing episode, may be useful appropriately to direct therapy to those patients with cough who have relevant acid reflux.

Weakly acidic reflux in patients with chronic unexplained cough during 24 hour pressure, pH, and impedance monitoring

BACKGROUND AND AIMS

Acid gastro-oesophageal reflux is one of the most important causes of chronic cough. The response to acid suppression in these patients is not as good as in patients with heartburn but improvement with antireflux surgery has been reported, suggesting the involvement of a non-acidic gastric component in the refluxate. Less acidic reflux may produce symptoms such as regurgitation or chest pain. We investigated whether chronic cough might be associated with weakly acidic reflux.

METHODS

We studied 28 patients with chronic cough using 24 hour ambulatory pressure-pH-impedance monitoring. Manometry was used for precise recognition of cough and impedance-pHmetry to detect acid (pH <4), weakly acidic (pH 7-4), and weakly alkaline (impedance drops, pH >/=7) reflux. A symptom association probability (SAP) analysis was performed for each type of reflux.

RESULTS

Analysis was completed in 22 patients with 24 cough events (5-92)/patient. The majority of cough events (69.4%) were considered "independent" of reflux whereas 30.6% occurred within two minutes of a reflux episode. Half of these (49%) were "reflux cough" sequences, involving acid (65%), weakly acidic (29%), and weakly alkaline (6%) reflux. Ten patients (45%) had a positive SAP between reflux and cough: five with acid, two with acid and weakly acidic, and three only with weakly acidic reflux.

CONCLUSIONS

Ambulatory pressure-pH-impedance monitoring with SAP analysis allowed precise determination of the temporal association between cough and gastro-oesophageal reflux (acid, weakly acidic, and weakly alkaline) and identification of a subgroup of patients with chronic cough clearly associated with weakly acidic gastro-oesophageal reflux.

The prevalence of gastroesophageal reflux disease in adult asthmatics

BACKGROUND

Asthma and gastroesophageal reflux disease (GERD) often coexist. However, the results of the studies investigating the prevalence of GERD among patients with asthma vary greatly.

STUDY OBJECTIVE

To investigate the prevalence of GERD in adult patients with asthma.

SUBJECTS AND METHODS

The basic study population consisted of 2,225 asthmatic patients who were treated in six specialist-headed hospitals during 1 year. From the common computer-based discharge register, every 14th patient was randomly selected for the study. Ninety of the 149 contacted patients (60%) agreed to participate in the study. Twenty-four-hour esophageal pH monitoring was performed on all patients.

RESULTS

GERD was found in 32 of the patients (36%). Eight of these patients (25%) were free from classical reflux symptoms. Forty-seven of the 90 patients (52%) presented with typical reflux symptoms. Twenty-four of these patients (51%) were found to have abnormal acidic reflux.

CONCLUSIONS

According to the current study, one third of adult patients with asthma have GERD. These patients often do not have typical reflux symptoms. However, the presence of typical reflux symptoms in an asthmatic patient does not seem to guarantee the presence of abnormal acidic reflux.

Impact of wheezing after respiratory syncytial virus infection on health-related quality of life

BACKGROUND

Respiratory syncytial virus (RSV) lower respiratory tract infection (LRTI) is often followed by recurrent wheezing episodes during childhood. The effect of postbronchiolitis wheezing on the well-being of the child is not known. This study aimed to determine the impact of RSV LRTI hospitalization before age 13 months on health-related quality of life (HRQoL) at age 3 years.

METHODS

HRQoL was measured in a previously described cohort of children with a history of RSV infection and compared with control term children from the open population. HRQoL was determined during the winter season in index and control children. We used a validated questionnaire, which measures the health status of children in 13 domains weighted by the impact of the health status problems on well-being. The lung domain was the focus of this study. In addition daily respiratory symptoms of the index children were recorded prospectively up to age 3 years and correlated with HRQoL scores.

RESULTS

HRQoL was lower in index children (n = 128) than in control children (n = 340) for the lung, gastrointestinal tract and sleeping domains. HRQoL scores for social and developmental domains were similar for index and control children. As anticipated the largest difference between index and control children was found in the lung domain (77.6 +/- 2.2 vs. 93.9 +/- 0.8, P < 0.01). HRQoL in the lung domain was lower during the winter than during the summer season (77.6 +/- 2.2 vs. 85.6 +/- 1.9, P < 0.01), which was explained by increased airway morbidity during the winter season. We found a high correlation between lung HRQoL scores and total number of wheezing days during follow-up.

CONCLUSIONS

Postbronchiolitis wheezing has broad implications for long-term well-being of children. Decreased HRQoL was attributed to postbronchiolitis wheezing, but not to preexistent risk factors, such as premature birth. This study underscores the importance of developing new strategies to prevent and treat long term airway morbidity after RSV LRTI.

Cough. 3: chronic cough and gastro-oesophageal reflux

The pathogenesis and clinical features of gastro-oesophageal reflux related cough are complex and the diagnostic tests available are of limited reliability. Treatment needs to be tailored to the specific needs of individual patients and other possible causes of chronic cough should be investigated. Treatment should only be considered to have failed when cough persists after administration of proton pump inhibitors at an adequate dosage for a sufficient length of time.

Recent clinical investigations examining the association of asthma and gastroesophageal reflux

For more than a decade, investigations have examined the association between asthma and gastroesophageal reflux (GER), and have demonstrated that the presence of esophageal acid events is associated with respiratory symptoms. The most current research shows that GER is prevalent in patients with asthma, that esophageal acid may alter bronchial hyperresponsiveness, and that medical or surgical GER therapy may improve asthma outcome in selected asthma patients. Further research will build on our current knowledge base and, hopefully, enable us to better identify those patients with asthma who will most benefit from reflux therapy.

Severe gastroesophageal reflux is associated with reduced carbon monoxide diffusing capacity

OBJECTIVE

To assess whether severe gastroesophageal reflux (GER) is associated with abnormalities in lung function including measures of lung volume and gas diffusion.

METHODS

Data from 147 patients with obesity (body mass index [BMI] range, 31.7 to 70 kg/m(2)) who presented for obesity surgery was analyzed retrospectively. A questionnaire was completed preoperatively that included a history of GER, frequency and severity of symptoms, investigations, and medications used. A history of lung disease, sleep-disordered breathing, and smoking also was obtained. A physician who was blinded to lung function graded GER severity prospectively by the results of pH monitoring and/or gastroscopy, and medication use. Spirometry, lung volumes, and gas transfer were measured preoperatively.

RESULTS

Patients with severe GER had reduced levels of the diffusing capacity of the lung for carbon monoxide (DLCO) [21.1 mL/min/mm Hg; 95% confidence interval (CI), 18.9 to 23.2], as measured by CO transfer, compared with those patients without GER (26.3 mL/min/mm Hg; 95% CI, 24.4 to 28.2; p = 0.001). This remained significant after adjusting for age, gender, BMI, and smoking history. Gas transfer corrected for lung volume also was reduced in the group with severe GER (4.6 mL/min/mm Hg per L; 95% CI, 4.3 to 4.9) compared to the group without GER (5.3 mL/min/mm Hg per L; 95% CI, 5.1 to 5.5; p = 0.001). There was no significant difference in other measures of lung function.

CONCLUSIONS

Severe GER is associated with an impairment of gas exchange. This may be due to microaspiration of gastric acid or fluid into the airways.

Temporal correlation between chronic cough and gastroesophageal reflux disease

Reflux disease (GERD) and chronic cough often coexist, but a temporal correlation using the symptom association probability has not been reported. Our aim was to determine if a temporal correlation exists between cough and GERD. Sixty-one patients with chronic cough had esophageal pH monitoring with sensors 5 and 20 cm above the LES. The symptom (SI) and symptom sensitivity (SSI) indices and the symptom association probability (SAP) were used to test cough-reflux association. Pathological reflux was defined as the percentage of time pH < 4 exceeded 4.2%. A significant temporal association between cough and distal reflux was made in 35% of patients by SAP compared with only 14.8% by SI and SSI alone (P < 0.002). Patients with pathologic reflux had a greater likelihood of a temporal symptom correlation (57.1%) when not on acid-blocking medications. In conclusion, a temporal association between cough and distal reflux exists in one third of patients, especially those with pathological reflux. The SAP is a more sensitive measure of temporal association than SI or SSI.