Simplifying the diagnosis and treatment of gastroesophageal reflux and airway diseases

Possible mechanisms of influence of esophageal acid on airway hyperresponsiveness

Airway hyperresponsiveness is among the defining phenomena in asthma. In this article, 3 mechanisms are reviewed to explain how gastroesophageal reflux (GER) may influence airway hyperresponsiveness. First, microaspiration may cause not only direct tissue injury, but may also trigger vagal reflexes. Second, acid infusion of the esophagus in a dog model and in humans has been shown to result in vagally mediated reflexes leading to bronchoconstriction. These reflexes have been studied using immunohistochemical techniques. Third, neuroinflammatory reflexes have been found to play a role in airway responses through the release of tachykinins, including substance P and neurokinin A. Combined, these 3 mechanisms may lead to an increase in vagal efferent impulses that can cause or augment airway hyperresponsiveness. Studies indicate that there is an increase in airway responsiveness in asthma patients who have documented GER. Further, based on the reported number of reflux episodes occurring during 24-hour pH monitoring, airway hyperresponsiveness to methacholine challenge tends to increase as GER worsens.

Diagnosis and treatment of gastroesophageal reflux in children and adolescents with severe asthma

BACKGROUND

The ability of gastroesophageal reflux disease to provoke asthma is controversial. Recent reports have suggested that reflux to the proximal esophagus may be especially likely to aggravate asthma, but the prevalence of proximal reflux in children and adolescents is poorly documented. It is also unclear how sensitive and specific the commonly used tests of reflux, barium swallow, and scintiscan are compared with pH probe studies in young patients. There is limited information on the effectiveness of the combination of H2 blockers and prokinetic agents in controlling reflux in children.

OBJECTIVE

There were three objectives in this study: (1) to determine the prevalence of both proximal and distal gastroesophageal reflux in asthmatic children and adolescents; (2) to determine the sensitivity, specificity, positive and negative predictive values of barium swallow and scintiscan studies; and (3) to determine the effectiveness of standard antireflux pharmacotherapy.

METHODS

A 24-hour, 2-channel pH probe study was carried out in 79 asthmatic children aged 2 to 17 years. The prevalence of abnormal proximal and distal gastroesophageal reflux was calculated from the findings. In 63 of these patients, barium swallow and Technetium99 scintiscan were carried out and the findings used to calculate the sensitivity, specificity, positive and negative predictive value of these studies relative to pH probe. In 11 subjects a follow-up, 24-hour pH probe was carried out after at least 3 weeks of therapy with an H2 blocker and prokinetic agent to determine the efficacy of therapy.

RESULTS

There was abnormal proximal esophageal reflux in 64.5% of subjects and abnormal distal reflux in 73.4%. The sensitivity, specificity, positive and negative predictive values of barium swallow were 46.1%, 83.3%, 82% and 51%, respectively. Those of scintiscan were 15%, 72.7%, 50% and 32%, respectively. Of 11 subjects studied by repeat pH probe, 10 had persistent abnormal reflux.

CONCLUSION

Abnormal reflux into the proximal esophagus occurs in the majority of asthmatic children with difficult-to-control disease. The barium swallow and scintiscan compare poorly with pH probe in diagnosing reflux. Treatment of reflux with recommended does of H2 blockers and prokinetic agents has a high failure rate, and follow-up studies are essential.

Cost-effective management of dyspepsia and gastroesophageal reflux disease

Dyspepsia and heartburn are common symptoms in primary care practice. This article outlines the diagnosis and management of these problems with an emphasis on cost-effectiveness as well as the prevention of complications. It reviews what evaluations and treatments have been shown in the literature to be helpful and which have been found to be ineffective or much more expensive without clear benefit. It also clarifies the various diseases that can present as dyspepsia and refers readers to the appropriate articles included in this book.