ESSENTIALS OF DIAGNOSIS
Heartburn; may be exacerbated by meals, bending, or recumbency.
Typical uncomplicated cases do not require diagnostic studies.
Endoscopy demonstrates abnormalities in one-third of patients.
GERD is a condition that develops when the reflux of stomach contents causes troublesome symptoms or complications. It affects 20% of adults. The two most common symptoms are heartburn and regurgitation. However, other symptoms of GERD include dyspepsia, dysphagia, belching, chest pain, cough, and hoarseness. Although most patients have mild disease, esophageal mucosal damage (reflux esophagitis) develops in up to one-third and more serious complications develop in a few others. Several factors may contribute to GERD (eFigure 15–19).
Pathophysiology of esophageal reflux disease. LES, lower esophageal sphincter. (Reproduced, with permission, from Hammer GD, McPhee SJ [editors]. Pathophysiology of Disease: An Introduction to Clinical Medicine, 8 ed. McGraw-Hill, 2019.)
A. Dysfunction of the Gastroesophageal Junction
The antireflux barrier at the gastroesophageal junction (eFigure 15–20) depends on LES pressure, the intra-abdominal location of the sphincter (resulting in a “flap valve” caused by angulation of the esophageal-gastric junction), and the extrinsic compression of the sphincter by the crural diaphragm. In most patients with GERD, baseline LES pressures are normal (10–35 mm Hg). Most reflux episodes occur during transient relaxations of the LES that are triggered by gastric distention by a vagovagal reflex. A subset of patients with GERD have an incompetent (less than 10 mm Hg) LES that results in increased acid reflux, especially when supine or when intra-abdominal pressures are increased by lifting or bending. A hypotensive sphincter is present in up to 50% of patients with severe erosive GERD.
Normal gastroesophageal junction. In this picture, the gastroesophageal junction is defined by the junction of the normal pearly white esophageal mucosa with the normal pinkish gastric mucosa. (Used, with permission, from Michelle Nazareth, MD.)
Hiatal hernias are found in one-fourth of patients with nonerosive GERD, three-fourths of patients with severe erosive esophagitis, and over 90% of patients with Barrett esophagus. They are caused by movement of the LES above the diaphragm, resulting in dysfunction of the gastroesophageal junction reflux barrier. Hiatal hernias are common and may cause no symptoms (eFigure 15–21, 15–22); however, in patients with gastroesophageal reflux, they are associated with higher amounts of acid reflux and delayed esophageal acid clearance, leading to more severe esophagitis and Barrett esophagus. Increased reflux episodes occur during normal swallowing-induced relaxation, transient LES relaxations, and straining due to reflux of acid from the hiatal hernia sac into the esophagus.
Irregular Z line at the gastroesophageal junction. This photo at the gastroesophageal junction shows the irregular Z-line separating esophageal (squamous epithelial) from ...