Gastroesophageal reflux disease (GERD) is getting a lot of attention these days. That’s partly because of the frequency of its cardinal symptoms but more importantly because of growing awareness that these symptoms may be harbingers of a serious disorder. Also, the advent of newer pharmacologic agents has expanded treatment options for the disease.
Q. What is GERD?
A. GERD is the syndrome defined by the sequelae of upward propagation of gastric contents, most specifically gastric acid, into the esophagus. The classic symptoms, heartburn and regurgitation, are fairly specific but unfortunately not terribly sensitive for the diagnosis. The definition of GERD also includes the various complications of chronic reflux esophagitis, such as ulceration, benign (so-called peptic) stricture, and metaplastic epithelium leading potentially to cancer.
Q. What causes GERD?
A. Gastroesophageal reflux disease results from an abnormality of esophageal and lower esophageal sphincter (LES) motility. Under normal circumstances, the LES is tonically contracted, preventing upward migration of gastric acid, gastric juice, and bile into the esophagus, where the squamous epithelium is less acid-resistant than the mucus-secreting columnar epithelium of the stomach. The LES remains closed until a peristaltic wave propagates down the esophagus to the sphincter area, when muscular relaxation occurs.
The primary factor in the development of GERD is transient, intermittent, and inappropriate relaxation of the LES. Chronic low LES pressure occurs in only about 15 percent of GERD patients. When LES pressure is low, gastric contents, with their normally acid pH, reflux into the esophagus and cause symptoms. Obviously, symptoms would tend to be worse at night, when recumbency reduces the effect of gravity, and after meals, when there is a postprandial acid surge.
Q. How common is GERD?
A. By definition, almost everyone has had an episode of reflux—the substernal burning pain we call “heartburn,” usually following dietary indiscretion. Actual prevalence figures are hard to establish because many people do not report symptoms. In a 1976 study of 1000 adults, approximately 38 percent had heartburn on a daily, weekly, or monthly basis (one third in each category). A potential flaw of the research was the study group itself, which included hospitalized patients, attendees at a gastroenterology clinic, and pregnant women, all of whom might be expected to have higher-than-average rates of reflux. However, a similar 1997 study done at the Mayo Clinic in Rochester, Minn., found surprisingly similar rates. All in all, any condition in which the major symptom manifestation occurs in nearly 40 percent of the population is a condition to be reckoned with.
At the same time, it must be realized that a large number of patients have reflux without heartburn: Some are completely asymptomatic, and some have only atypical manifestations of the disease.