Measurement of gastric emptying in gastroesophageal reflux-related chronic cough

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.

Gastric motility following ingestion of a solid meal in a cohort of adult asthmatics

BACKGROUND/AIMS

Asthmatics have abnormal esophageal motility and increased prevalence of gastroesophageal reflux disease (GERD). The contribution of gastric motility is less studied. We studied gastric myoelectrical activity, gastric emptying (GE) and their association with GERD symptoms and vagal function in adult asthmatics.

METHODS

Thirty mild, stable asthmatics and 30 healthy controls underwent real-time ultrasonography and 1 hour pre- and post-prandial cutaneous electrogastrography, following a test meal (480 kcal, 60% carbohydrate, 20% protein, 20% fat and 200 mL water). The percentage of normal slow waves and arrhythmias, dominant frequency and power, frequency of antral contractions, gastric emptying rate (GER) and antral motility index (MI) was calculated. Twenty-seven asthmatics underwent gastroscopy and in all subjects GERD symptoms were assessed by a validated questionnaire. Vagal function parameters were correlated with gastric motility parameters.

RESULTS

The asthmatics (37% male; 34.8 ± 8.4 years) and controls (50% male; 30.9 ± 7.7 years) were comparable. None had endoscopic gastric pathological changes. Twenty asthmatics described GERD symptoms. Twenty-two (73.3%) asthmatics showed a hypervagal response. Compared to controls, asthmatics had delayed GER and lower MI, lower percentage of normal gastric slow waves, more gastric dysrythmias and failed to increase the post-prandial dominant power. There was no correlation of GE and cutaneous electrogastrography parameters with presence of GERD symptoms or with vagal function.

CONCLUSIONS

Asthmatics showed abnormal gastric myoelectrical activity, delayed GE and antral hypomotility in response to a solid meal compared to controls. There was no association with vagal function or GERD symptom status.

Advancing gastric emptying studies: standardization and new parameters to assess gastric motility and function

For many years, gastric emptying (GE) studies were performed using various local protocols and different radiolabeled meals. This lack of standardization and normal values made the test results unreliable and difficult to compare from one site to another. A recent consensus has been published that now provides guidance and standardization on how to perform a radiolabeled solid-meal GE study. It is widely recognized, however, that simple measurement of total GE of a solid meal often does not provide an answer to the etiology of symptoms for a large number of patients who present with functional dyspepsia. Advances in our understanding of the different roles of the fundus and antrum and their complex interaction with the proximal small bowel and central nervous system have led to the development of new methods to study gastric motility. This review describes how a more comprehensive approach to studying GE is needed and how this will lead to better diagnosis and treatment for patients referred for GE studies.

Temporary gastric neuromodulation for intractable nausea and vomiting

INTRODUCTION

Gastric neuromodulation (GNM) has been advocated for the treatment of drug refractory gastroparesis or persistent nausea and vomiting in the absence of a mechanical bowel obstruction. There is, however, little in the way of objective data to support its use, particularly with regards to its effects on gastric emptying.

METHODS

Six patients (male-to-female ratio: 4:2, mean age: 49 years, range: 44-57 years) underwent the GNM between April and August 2010. Three patients had confirmed slow gastrointestinal transit. Aetiology included previous gastric surgery in two, diabetes in one and idiopathic nausea and vomiting in three patients. GNM pacing wires were placed endoscopically and left in situ for seven days. Patients underwent gastric scintigraphy before and 24 hours after the commencement of GNM. Total gastroparesis symptom scores (TSS), weekly vomiting frequency scores (VFS), health-related quality of life (using the SF-12(®) questionnaire), gastric emptying, nutritional status and weight were compared before and after GNM.

RESULTS

TSS improved after GNM in comparison with baseline data. VFS improved in three of four symptomatic patients. The SF-12(®) physical composite score improved in four patients (27.5 vs 34.3) and the mental composite score improved in five patients (34.9 vs 35.9). All patients reported an improvement in oral intake. A significant weight gain (mean: 1kg, range: 0.3-2.4kg) was observed over seven days. Gastric emptying half-time improved in four patients.

CONCLUSIONS

GNM improved upper gastrointestinal symptoms, quality of life and nutritional status in patients with intractable nausea and vomiting. GNM merits further investigation.

Chronic Cough Due to Gastroesophageal Reflux Disease

OBJECTIVES

To critically review and summarize the literature on cough and gastroesophageal reflux disease (GERD), and to make evidence-based recommendations regarding the diagnosis and treatment of chronic cough due to GERD.

DESIGN/METHODOLOGY

Ovid MEDLINE literature review (through March 2004) for all studies published in the English language and selected articles published in other languages such as French since 1963 using the medical subject heading terms "cough," "gastroesophageal reflux," and "gastroesophageal reflux disease."

RESULTS

GERD, singly or in combination with other conditions, is one of the most common causes of chronic cough. In patients with normal chest radiographic findings, GERD most likely causes cough by stimulation of an esophageal-bronchial reflex. When GERD causes cough, there may be no GI symptoms up to 75% of the time. While 24-h esophageal pH monitoring is the most sensitive and specific test in linking GERD and cough in a cause-effect relationship, it has its limitations. In addition, there is no general agreement on how to best interpret the test, and it cannot detect non-acid reflux events. Therefore, when patients fit the clinical profile that has a high likelihood of predicting that GERD is the cause of cough, antireflux medical therapy should be empirically instituted. While some patients improve with minimal medical therapy, others require more intensive regimens. When empiric treatment fails, it cannot be assumed that GERD has been ruled out as a cause of chronic cough. Rather, an objective investigation for GERD is then recommended because the empiric therapy may not have been intensive enough or medical therapy may have failed. Surgery may be efficacious when intensive medical therapy has failed in selected patients who have undergone an extensive objective GERD evaluation.

CONCLUSIONS

Accurately diagnosing and successfully treating chronic cough due to GERD can be a major challenge.

Delayed gastric emptying in gastroesophageal reflux disease: the role of malrotation

The association between gastroesophageal reflux (GER) and intestinal malrotation (IM) has been well described. Delayed or impaired gastric emptying in IM is thought to be a contributing factor in the development of gastroesophageal reflux disease (GERD). The current study assessed the role of malrotation in delayed gastric emptying in children with GERD. We also evaluated the interactions between GERD, malrotation, gastric pH abnormalities, and gastric dysmotility. Sixty-seven patients between 1 and 5 years of age (mean 3.08+/-1.2) and with symptoms of GER, such as emesis, reactive or recurrent lung disease, and/or growth retardation, were studied in 2001-2005. Upper and lower gastrointestinal contrast studies were performed for the diagnosis of malrotation. Gastric motility was evaluated with a liquid gastric emptying protocol. GER was documented by upper gastrointestinal studies, scintigraphy, and/or 24-h pH monitoring. In our series of 44 children with GERD, there was an unexpectedly high incidence of IM: 54.5% (24/44). IM has previously been known to occur in 25% of patients with GERD. GERD was found in 24 (82.7%) of 29 patients with IM. Mean nuclear gastric emptying (MNGE) was 51.6+/-8.04 min in patients with isolated GERD and 96.6+/-20.5 min in children with IM and GERD. There was a statistically significant difference in MNGE time (p<0.05) between children with primary GERD and in those with GERD and IM. Esophageal pH monitoring showed that mean fraction time below pH 4 was 7.06+/-1.1% in patients with isolated GERD and 14.7+/-4.1% in patients with IM and GERD. GERD is common in children between 1 and 5 years old. Using gastric emptying studies and esophageal pH monitoring, we have shown that gastric dysmotility and esophageal pH abnormalities are highly prevalent, especially in children with malrotation compared with children with isolated GERD. These findings suggest that malrotation is an important factor responsible for delayed gastric emptying in GERD. Hence, we recommend that all infants and children with GERD and delayed gastric emptying undergo careful evaluation for malrotation.

Gastro-oesophageal reflux and bronchial asthma: current status and future directions

In recent years there have been several reports suggesting an association between bronchial asthma and gastro-oesophageal reflux; however a cause and effect relationship has not been proven yet. Confirmation of such a relationship is likely to have far reaching implications on the management of asthma. Reliable assessment of this issue is hampered by the presence of various lacunae in most of the published studies. Hence it is essential to carefully examine the strength of data suggesting a link between asthma and reflux. This article critically analyses currently available literature on the subject (including published reviews, meta-analyses, and randomised clinical trials in the English language) and summarises valid conclusions that can be drawn; it also proposes a framework for future studies to resolve the issue.