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Gastroesophageal reflux (GER) is the spontaneous passage of gastric contents into the esophagus. When it reaches the mouth, it is also called regurgitation. GER is a normal physiologic process that occurs throughout the day in healthy infants, children, and adults. When GER causes bothersome symptoms, GER becomes GERD, GER disease. The signs and symptoms that have been attributed to GERD range from chest pain and heartburn to cough and pneumonia (Table 389-1). However, 1 of the diagnostic challenges with bothersome symptoms is proving that these symptoms are, in fact, reflux related (rather than just associated) to avoid ineffective treatment of symptoms. This concern of ineffective treatment or overtreatment is of utmost importance in the face of growing evidence that medical and surgical reflux therapies (acid suppression and fundoplication) can have short- and long-term side effects.
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PATHOGENESIS AND EPIDEMIOLOGY
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GER occurs when the lower esophageal sphincter relaxes and allows for gastric contents to enter the esophagus. These transient lower esophageal sphincter relaxations (TLESRs) are normal, physiologic processes that can be measured using esophageal manometry. Esophageal manometry studies show that TLESRs account for 80% to 90% of all reflux episodes. In patients with pathologic amounts of reflux, there are more TLESRs present and those that are present are more likely to allow gastric contents to pass into the esophagus. The remaining reflux episodes occur when there is increased abdominal pressure overcoming the lower esophageal sphincter pressures. The majority of reflux occurs in the immediate postprandial period when there is increased volume of gastric contents that can be refluxed at the time of TLESRs.
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There are 3 main types of reflux (acidic with a pH of < 4, weakly acidic with a pH of 4–7, and nonacid reflux with a pH of > 7). In pediatrics, the convention is to designate all reflux with a pH greater than 4 as nonacid because it cannot be detected by pH sensors in the esophagus. The type of esophageal reflux varies depending on the timing of the reflux episode relative to a meal; reflux episodes in the 1 to 2 hours after a meal are typically weakly or nonacidic and those occurring 3 to 4 hours or more after a meal are predominately acidic. Infants, who only drink formula or breast milk every 2 to 3 hours, are almost always refluxing nonacidic formula/breast milk, which may explain the lack of efficacy of ...