A history of recurrent heartburn along with a positive response to antacids or acid-suppressing medication is adequate to diagnose Acid Reflux Disease. Specific testing is reserved for patients who have (1) Acid Reflux Disease plus alarm symptoms of dysphagia, weight loss, or gastrointestinal bleeding; (2) Acid Reflux Disease of sufficient chronicity (e.g., 5 years) to raise concern for Barrett's esophagus; and (3) suspected Acid Reflux Disease with atypical symptoms, such as chest pain or oropharyngeal, laryngeal, or airway symptoms.
Establishing Acid Reflux Disease as a Cause of Nonheartburn Symptoms
Currently, the preferred method for establishing Acid Reflux Disease as the cause of symptoms (e.g., chest pain, wheezing) is an empirical trial of acid suppression with a PPI (e.g., omeprazole, 20 mg twice daily), which normalizes esophageal acidity in approximately 95% of subjects. In some instances, a bedtime dose of a histamine H2-receptor antagonist (e.g., ranitidine, 300 mg) is added to reduce the possibility of nocturnal acid breakthrough. The treatment period in which to expect a satisfactory response is 2 to 4 weeks for chest pain and 2 to 3 months for inflammatory disease of the airway. Resolution of the symptoms supports Acid Reflux Disease as possibly causal. Confirmation may be obtained by relapse when medication is withdrawn and by a subsequent positive response to re-treatment, as confirmed by documenting control of esophageal acidity on pH monitoring while undergoing PPI therapy. Failure of symptoms to improve with PPI therapy is not generally an indication for antireflux surgery (see later) but rather an indication to search for another disease. A rarely used alternative is the Bernstein test, in which acid (0.1 N HCl, pH 1.1) or saline (control) is perfused through a catheter positioned in the midesophagus. If symptoms typical of those that occur spontaneously develop with acid but not saline, the test is considered positive for Acid Reflux Disease.
Tests for Reflux
Documenting acid reflux is not necessary except when symptoms fail to respond to PPI therapy or when surgery is being considered. Esophageal pH monitoring, the “gold standard” for identifying acid reflux, is performed by fixing a small pH probe in the esophagus, 5 cm above the LES, and recording all episodes in which esophageal pH drops to less than 4 over a 24- to 48-hour period. The number and duration of each acidic event, when combined, yield a value for total esophageal acid contact time. Total acid contact times of greater than 5% are abnormal and consistent with a diagnosis of Acid Reflux Disease. An event marker activated by the patient also allows symptoms to be related to episodes of esophageal acidity. An upper gastrointestinal series can detect grossly abnormal reflux by observing movement of barium from the stomach to the esophagus with the patient in the head-down position. It has low sensitivity but, when positive, has high predictive value. The positive predictive value is much lower, however, if reflux is induced by having the subject sip water through a straw in the head-down position. This test is rarely useful for therapeutic decisions.
Tests for Esophageal Injury
Endoscopic signs.
Tests of Esophageal Motor Function
An upper gastrointestinal series or barium swallow is valuable for identifying gross reflux and marked abnormalities in esophageal anatomy (e.g., hiatal hernia, diverticulum) and peristaltic and sphincter function. More subtle abnormalities, however, require esophageal manometry. Low mean LES pressure (<10 mm Hg) is a specific but insensitive marker of Acid Reflux Disease, with 60% of patients having normal values. Currently, the major uses of esophageal manometry in Acid Reflux Disease are to (1) position the pH probe for reflux testing, (2) exclude motor disease (achalasia, scleroderma), and (3) quantify peristaltic amplitudes before surgical fundoplication. If contraction amplitudes average less than 30 mm Hg, a partial (Toupet) rather than complete (Nissen) wrap may be preferable to avoid postoperative dysphagia.
Labels: GERD diagnosis