Gastroesophageal Reflux and Asthma: Pathogenesis, Diagnosis, and Therapy

Gastroesophageal reflux is one of the most common problems that physicians encounter in all specialties; it may be defined as the retrograde flow of gastric contents across an incompetent gastroesophageal junction into the esophagus. The fluid may include not only the acidic secretions of the stomach, but also duodenal juice that may have backwashed across the pylorus. Although the prevalence of reflux and its primary symptom, heartburn, is difficult to ascertain, approximately 10% of the general population admits to symptoms of gastroesophageal reflux daily, and as many as 40% experience heartburn monthly. Heartburn, defined as a retrosternal burning pain that travels upward and typically aggravated by position (reclining) and certain foods, reaches its maximal frequency during pregnancy, when 25 to 40% of patients may have daily symptoms. The magnitude of the problem is illustrated not only by its prevalence, but also by its potential morbidity, which includes esophageal as well as respiratory complications. Among the latter, researchers have reported the association of gastroesophageal reflux with apnea and near-miss sudden infant death syndrome in children, and pulmonary fibrosis and recurrent laryngitis have been reported in adults. Reflux-induced recurrent pneumonia, recurrent bronchitis, bronchiectasis, and chronic asthma have been reported in both children and adults. Several studies have confirmed the relationship that gastroesophageal reflux and asthma go beyond the expected coincidence of two common diseases. Between 1961 and 1965 Urschel and Paulson evaluated 636 patients with hiatus hernia or documented gastroesophageal reflux and reported that more than 60% of the patients had respiratory symptoms, whereas 39% had gastrointestinal symptoms alone. There were a variety of pulmonary conditions present in these patients: cough in 47%, bronchitis in 35%, asthma or wheezing in 16%, pneumonitis in 16%, hemoptysis in 13%, and hoarseness in 12%. These investigators suggested that the onset of asthma in late childhood or adulthood or the development of severe bronchopulmonary symptoms in a nonsmoker without obvious allergies or the presence of recurrent pneumonitis in the midlung fields are clinical settings that are highly suggestive of gastroesophageal reflux. Restrospective analysis found that 24 of 27 asthmatic patients who underwent surgical correction of gastroesophageal reflux had significant improvement in their asthma. Kjellen and colleagues examined the frequency of "esophageal dysfunction" in 97 asthmatic patients. The criteria used to define esophageal dysfunction in this study included the presence of hiatus hernia, esophageal dysmotility, lower esophageal sphincter hypotension, or positive acid perfusion test. Four percent of the patients met all four criteria, whereas 10% had three criteria, 28% had two criteria, and 25% had one; overall, 65 of the 97 asthmatic patients had evidence of esophageal dysfunction. Perpina and coworkers assessed the magnitude of reflex bronchoconstriction, triggered by gastroesophageal reflux during a Bernstein test, by measuring pulmonary function (forced expiratory spirograms, flow-volume loops, and airway resistance). In a group of 21 adult asthmatics and 15 control subjects, changes in pulmonary function parameters occurred only in asthmatics who had symptomatic gastroesophageal reflux and not in asthmatics without symptomatic reflux or in any of the normal control population. However, the investigators believed that, although changes were statistically significant (p < 0.05), the magnitude