A significant percentage of people with asthma suffer from gastroesophageal reflux disease.

Gastroesophageal reflux disease (GERD) can trigger an asthma attack, and GERD symptoms are more common in those with asthma than in control populations.¹ Although the connection between GERD and asthma has not been fully determined, it is estimated that 24% to 98% of patients with asthma also have GERD.² People with severe, chronic asthma who do not respond well to treatment are more susceptible to GERD.³ Robert A. Balk, section director of pulmonary and critical care medicine at Rush University Medical Center and professor of internal medicine at Rush Medical College, Chicago, says, “Asthma can make GERD worse and untreated GERD can make asthma worse.”

GERD can include “any of the symptoms resulting from tissue damage caused by reflux of gastric contents into the esophagus.”⁴ For example, in Barrett’s esophagus, changes in the cells in the lining of the esophagus are associated with an increased risk of cancer.⁵ More commonly, GERD is simply the backward flow of gastric contents into the esophagus.⁶ Symptoms associated with GERD not only affect the esophagus, but adversely affect other sites.

Symptoms
Esophageal GERD symptoms include the primary signs of recurrent heartburn and/or regurgitation (usually after large meals) and can be exacerbated by position changes, such as bending forward or lying supine. Other esophageal symptoms include chest pain and frequent hiccups.⁶

Extraesophageal symptoms involve the ear, nose, throat, and pulmonary system. The GERD complications involving the ear, nose, and throat are aphthous ulcers, chronic throat clearing, hoarseness, laryngeal cancer, otitis media, otalgia, palatal dental erosion, pharyngitis, and vocal-cord granuloma. Pulmonary complications include asthma exacerbations, bronchiectasis, chronic bronchitis, chronic cough, idiopathic pulmonary fibrosis, and recurrent pneumonia.⁶

The Asthma Link
Some factors linking GERD and asthma are the absence of an allergic component, adult onset asthma, nocturnal cough, obesity, poor response to asthma therapy, and asthma attacks after heartburn or regurgitation.⁶ Most patients with mild symptoms find that one condition can exacerbate the underlying (subclinical) activity of the other.⁷ In a clinical review, Alexander et al⁷ explored the link between the overlapping conditions of GERD and asthma. There was decreased expiratory airflow and/or increased airway resistance in response to esophageal acid infusion.⁷ Increased bronchial reactivity to other stimuli was also seen in response to esophageal acid exposure. In addition, asthma patients with GERD showed autonomic dysfunction, with primarily hypervagal responsiveness.⁷

Direct alterations in ventilation were seen; subjects without asthma who experienced chest pain had increased minute ventilation and respiratory rates in response to esophageal acid infusion. This finding may mean that while minute ventilation is affected by GERD, lung function is not. It may also help to clarify why reflux treatment improves asthma, but does not have the same effect on pulmonary function.⁷ Microaspiration, which can increase the possibility of bronchial reactivity, does not seem to be a major factor in GERD.⁷

According to Alexander et al,⁷ the role of obesity in adult-onset asthma and GERD is unclear. More closely related to the idea that asthma causes GERD are mechanical factors such as airflow obstruction (which appears to trigger a cascade effect, possibly increasing negative pleural pressure that, in turn, increases the gradient pressure across the diaphragm). Air trapping seems to have a similar effect, flattening the diaphragm and, in turn, weakening the antireflux barrier.⁷

Some asthma medications can also increase the symptoms of GERD.⁷ Theophylline decreases the lower–esophageal-sphincter pressure, increases gastric acid secretion and esophageal acid contact times, and may increase reflux symptoms.¹ Oral beta-agonists have also been shown to increase reflux symptoms. In addition, prednisone has been shown to increase esophageal acid contact times significantly.¹ Esophageal acid may lower peak expiratory flow and may increase specific airway resistance in some people with asthma. Evidence¹ demonstrates a correlation between esophageal-acid events and airway reactivity.

GERD and sinus abnormality are interactive, and this connection is sometimes associated with cough. Brian L. Tiep, MD, is medical director, Respiratory Disease Management Institute, Los Angeles. He says, “Sinusitis and postnasal drip are among the most frequent causes of chronic cough. GERD is also a frequent cause. Typically, sinusitis and GERD are both present. Hence, the treatment of one, to the exclusion of the other, will result in treatment failure.”

Acute or chronic cough can be involved, with chronic defined, in this case, as present for at least 3 weeks.⁸ Tiep says, “There are many causes of chronic cough, and some coexist. A cough due to one cause will sometimes provoke one of the other causes of chronic cough. For example, sinusitis may lead to postnasal drip, which can irritate the esophagus at its origin, which can cause reflux, which can cause an irritated throat, which can make postnasal drip worse. This is a self-perpetuating cycle. All causes of chronic cough must be treated.”

Adult Treatments
Treatment options for GERD begin with lifestyle change. Management of GERD should focus on frequent, small meals; avoiding alcohol, tobacco, caffeine, peppermint, and carbonated beverages is also important, Balk notes. “Maintain an upright position for at least 3 hours after food and fluid ingestion; sleep with the head of the bed raised 15 to 20 cm,” he adds.

Over-the-counter (OTC) drugs that could be useful include antacids that are of rapid onset, that buffer the pH of gastric fluid, and that augment salivation and bicarbonate secretion. Alginic acid reduces reflux. These agents are short acting and relieve relatively mild symptoms.⁶

Histamine 2 blockers decrease acid production by inhibiting histamine stimulation of the parietal cell.⁶ These agents improve mild-to-moderate GERD when OTC drugs and lifestyle changes are insufficient. Proton-pump inhibitors (PPIs) suppress acid secretion by inhibiting the hydrogen/potassium adenosinetriphosphatase pump at the parietal cell.⁶ “The use of PPIs helps with GERD, but does not entirely eliminate symptoms; patients can still have nonerosive esophageal reflux disease,” Balk says.

Promotility agents inhibit dopamine receptors in the gastrointestinal tract, and this leads to increased release of acetylcholine from the myenteric plexus and stimulation of smooth muscle (promoting gastric emptying).⁶ “The best treatment approach is to evaluate all of the suspected diagnoses fully and adequately treat each,” Tiep says.

Patients may desire surgery because they do not wish to continue or increase medication, for financial reasons, because they have difficulty complying with medication regimens, for severe duodenogastroesophageal reflux, to relieve ongoing respiratory symptoms, or simply as a matter of preference.⁶ Nonetheless, “surgery is not always effective and can even make reflux symptoms worse. Surgery is used as the last option for management,” Balk says.

Pediatric Symptoms and Treatment
Foroutan and Ghafari⁹ investigated the relationship between chronic respiratory symptoms (chronic cough, recurrent pneumonia, asthma, and respiratory distress) and GERD in infants and children. Esophageal pH monitoring lasting 24 hours revealed gastroesophageal reflux as the cause of chronic respiratory symptoms in 42.2% of patients. The study indicated that GERD incidence was significantly higher in children who presented with chronic respiratory symptoms. The same study emphasized the importance of documenting significant reflux symptoms so that patients could receive proper treatment.

A study by Krishnan et al¹⁰ determined that the presence of gastric pepsin in tracheal aspirates was a reliable indicator of the microaspiration of gastric contents. A majority of children with both reflux and chronic respiratory symptoms had tracheal pepsin present. Children with asthma and children who present with developmental disabilities or neurological impairment are at higher risk for GERD, according to a study by Gold.¹¹

Miyazawa et al¹² determined, in a study of Japanese infants aged 1 to 12 months, that regurgitation is common in Japanese infants and decreases spontaneously with age; it is unaffected by milk volume, feeding interval, or body position after feeding. Lifestyle changes are still important, however, in relieving pediatric symptoms. Infants should have their heads elevated for up to 90 minutes after smaller, more frequent feedings and should be burped more often.⁶ Older children's symptoms may be eased if the heads of their beds are elevated 15 cm.⁶ Medication should be given to children and infants as indicated, and vigorous play should be avoided after eating. Carbonated drinks and foods that worsen symptoms should be avoided.⁶

Mary Anne Gates, RCP, performs sleep studies for Fulton County Health Center, Wauseon, Ohio.

References
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