Epidemiology

Children who have complex airway anomalies may be at higher risk for GERD. The exact prevalence of GERD in this population is unknown, though it is generally believed to be up to 70% in children who have complex medical conditions such as developmental delay or a history of TEF repair.

Pathophysiology

It is important to distinguish gastroesophageal reflux (GER) from GERD. Reflux occurs in normal individuals and is the inconsequential transient return of gastric contents into the esophagus, whereas GERD is defined as symptoms and/or mucosal changes related to excessive stomach acid regurgitation into the esophagus and oropharynx. Normal children demonstrate reflux into their esophagus multiple times per day, half of which are generally nonacidic in nature. Most episodes of GER in healthy individuals last less than 3 minutes, occur after meals, and cause few or no symptoms. In patients who have a history of swallowing dysfunction, there is evidence that episodes of reflux reaching the level of the proximal esophagus can cause airway damage and lead to pneumonia and respiratory tract infections. GERD may be caused by the altered thoracoabdominal pressure relationships that exist in children who have obstructive airway disease. Thus GERD is frequently a consequence rather than a primary cause of asthma symptoms or pulmonary disease in cystic fibrosis. Nevertheless, GERD may contribute to symptoms in these conditions.

GERD is also associated with weight gain and obesity in adults. Evidence for this association in pediatric age patients is less compelling. Nevertheless, clinical consideration of GERD in children should recognize the potential for interactions between excess weight, sleep-disordered breathing, asthma, and GERD.

Clinical Features/Symptoms

The symptoms of GERD affecting the airway are wide-ranging and include reactive airway disease, chronic cough, hoarseness, and difficulty swallowing. Mucosal abnormalities, including laryngeal edema, cobblestoning, and mucosal erythema, are nonspecific and do not prove the presence of reflux disease. Likewise, the absence of these findings does not exclude the presence of reflux.

True acidic GER can lead to mucosal injury in the larynx, conducting airways, and lung tissue. Acidic aspiration has long been known to cause mucosal sloughing and neutrophilic inflammation in alveolar tissue. There is evidence that acid reflux decreases laryngeal sensitivity, which could increase the risk for aspiration. Even nonacid reflux has been linked with a higher frequency of chronic lung disease in adults. On the other hand, poorly controlled asthma did not benefit from treatment with esomeprazole in patients who also had asymptomatic GERD in a 24-week placebo-controlled blinded study, which shows the difficulty in establishing the cause-effect relationship between reflux disease and laryngeal or airway symptoms. GERD may be present as a comorbidity that has no impact on the airway, or it may cause or exacerbate airway symptoms.

Data regarding the relationship between GERD and reconstructive airway surgery are sparse. Carron and colleagues demonstrated that simulated GER caused increased inflammation in cartilage grafts in a rabbit model after laryngotracheoplasty compared with controls. However, they were unable to show that reflux led to increased failure in the rabbit cartilage grafts. Several authors note that the treatment of children with proton pump inhibitor therapy to prevent GER improves outcomes in children after airway reconstruction, but these studies are all retrospective or represent just expert opinion. Zalzal and coworkers showed that children who had documented GERD had similar outcomes to those who did not have GERD after laryngotracheal reconstruction for laryngeal stenosis, irrespective of treatment. Regardless, there is sufficient concern that GER might negatively impact the results of airway reconstruction surgery that empiric antireflux therapy is often prescribed.

Diagnosis/Testing

The diagnosis of GERD depends on the demonstration that there are untoward consequences from reflux events and there is no single gold standard test. The diagnosis may be made presumptively based on clinical history alone when there is effortless regurgitation or heartburn. When regurgitation is not present in a child who has symptoms that could be caused by GERD, additional testing to detect reflux events or to document esophageal mucosal injury is possible. There is no single test that proves that reflux is responsible for a particular airway symptom, but a successful empiric trial of a proton pump inhibitor or H ₂ blocker is suggestive.

Children with persistent symptoms, or who need diagnostic studies prior to therapy, may undergo endoscopic evaluation or multichannel intraluminal impedance plus pH-metry (MII-pH). The latter is a 24-hour study that measures the frequency, duration/clearance, height of reflux, and duration of acid exposure in the esophagus by means of a catheter placed via the nose. Upper GI endoscopy permits visual inspection and biopsy of the esophageal mucosa to detect acid injury, ranging from microscopic abnormalities on histology to gross mucosal ulceration. However, there is controversy as to how to interpret the biopsy findings as due to acid reflux disease. Children who aspirate refluxed gastric contents may have pepsin identified in their bronchoalveolar lavage, though the absolute sensitivity and application of this test remain to be determined. Upper GI series with barium is not adequate for the diagnosis of GERD as the ingested contrast media commonly refluxes back into the esophagus, even in normal individuals. However, the test is commonly performed to evaluate the upper GI anatomy in patients who vomit or have dysphagia, and can help identify anatomic abnormalities such as esophageal stricture, hiatal hernia, or TEF.

Management

Standard medical therapy for GERD is acid suppression with either a proton pump inhibitor or H ₂ blocker. Both types of medication decrease acid production from gastric parietal cells. Tachyphylaxis, or decreased response, is an issue with histamine receptor antagonists such as ranitidine. Proton pump inhibitors appear to be more effective in treating erosive esophagitis than H2 blockers and in suppressing gastric acid production. It is important to remember that nonacid reflux will still occur even with adequate doses of medication. Many children may continue to complain of symptoms even on acid suppression with no evidence of inflammation on biopsies: the so-called nonerosive reflux disease (NERD).

The length of a treatment course is unclear. In adults with true erosive esophagitis, mucosal healing with proton pump inhibitors can take up to 2 months. However, many patients remain on medication indefinitely. Emerging data demonstrate several risks of long-term side effects of proton pump inhibitors (PPIs). These include adult data on decreased bone density as well as pediatric studies showing increased risk for respiratory infections and Clostridium difficile infection. This indicates that consideration of whether a child needs to continue long-term acid suppression is warranted. Children who symptomatically do not respond to acid suppression may require additional evaluation for EoE or gastroparesis, as discussed later in this chapter.

Medical therapy to limit the number of reflux episodes, irrespective of acidity, is quite limited. Metoclopramide has been used for GERD, but it has limited effectiveness and there is a high risk of side effects, including tardive dyskinesia. Children with recalcitrant GERD may benefit from antireflux surgery, as it effectively abolishes reflux and its attendant symptoms. Aspiration of refluxed gastric contents is controlled by fundoplication, but aspiration during swallowing is not affected. Fundoplication is associated with a number of complications, such as gagging/retching, gas bloat, or dumping syndrome, so it should be reserved for those patients who cannot be managed medically.