GASTROESOPHAGEAL REFLUX SCAN

Gastrointestinal reflux imaging refers to several methods of diagnostic imaging used to visualize and diagnose gastroesophageal reflux disease (GERD). GERD is one of the most common gastrointestinal problems among children or adults. It is defined as the movement of solid or liquid contents from the stomach backward into the esophagus. Purpose
The purpose of gastroesophageal reflux scanning is to allow the doctor to visualize the interior of the patient’s upper stomach and lower esophagus. This type of visual inspection helps the doctor make an accurate diagnosis and plan appropriate treatment.

Description
A brief description of gastroesophageal reflux disease is helpful in understanding the scanning methods used to diagnose it. Gastroesophageal reflux disease is the term used to describe the symptoms and damage caused by the backflow (reflux) of the contents of the stomach into the esophagus. The contents of the human stomach are usually acidic. Because of their acidity, they have the potential to cause chemical burns in such unprotected tissues as the lining of the esophagus.

Gastrointestinal reflux is common in the general American population. Approximately one adult in three reports experiencing some occasional reflux, commonly referred to as heartburn. About 10% of these persons experience reflux on a daily basis. Most persons, however, have only very mild symptoms. Occasionally, someone may experience a burning sensation as a result of gastrointestinal reflux. This symptom is described as reflux esophagitis when it occurs in association with inflammation.

Gastroesophageal reflux has several possible causes:
• An incompetent lower esophageal sphincter. Acid reflux can occur when the ring of muscular tissue at the boundary of the esophagus and stomach is weak and relaxes too far. Sphincter incompetence is the most common cause of gastroesophageal reflux. The acid juices from the stomach are most likely to flow backward through a weak sphincter when a person bends, lifts a weight, or strains. People with esophageal strictures or Barrett’s esophagus are more likely to experience gastroesophageal reflux than are others.

• Acid irritation. Gastric contents are acidic, with a pH lower than 3.9. This degree of acidity is very caustic to the lining of the esophagus; repeated exposures may lead to scarring. If the exposure is sufficiently severe or prolonged, strictures can develop. Occasionally, pancreatic enzymes or bile may also flow backward into the stomach and lower esophagus. These fluids are extremely acidic, with a pH lower than 2.0.

• Abnormal esophageal clearance. Clearance refers to the process of removing a substance from a part of the body, in this case the removal of stomach acid from the esophagus. Acid reflux is ordinarily washed out of the esophagus by the saliva that a person swallows over the course of a day. Saliva also contains some bicarbonate, which helps to neutralize the acidity of the stomach juices. During sleep, however, people swallow less frequently, which results in a longer period of contact between the acid contents of the stomach and the tissues that line the esophagus. The net result is a chemical injury. Sjögren’s syndrome, radiation to the oral cavity, and some medications (anticholinergics) also decrease the flow of saliva and can result in chemical injury. Such other medical conditions as Raynaud’s disease and scleroderma are often associated with abnormal esophageal clearance. Hiatal hernia is present in more than 90% of persons with erosive disease.

• Delayed gastric emptying. When outflow from the stomach is blocked or the stomach’s contractions are weakened, the partially digested food does not leave the stomach in a timely manner. This delay makes gastric reflux more likely to occur.

Heartburn associated with gastroesophageal reflux occurs 30–60 minutes after eating. It also occurs when a person is lying down. Most people who experience gastroesophageal reflux can obtain relief from heartburn with baking soda, bismuth subsalicylate (Pepto-Bismol), or antacid tablets. A pattern of symptom relief following a dose of one of these nonprescription remedies is usually enough to make the diagnosis of gastroesophageal reflux. Under these conditions, the results of a physical examination and laboratory tests are usually within normal limits.
Persons with complicated GERD, or those who do not respond to nonprescription heartburn remedies, require special examinations. There are several imaging methods used in the diagnosis of GERD:

Upper endoscopy
Upper endoscopy is the standard procedure for diagnosing GERD, determining the degree of tissue damage, and documenting the findings. A barium esophagography may be performed in addition to an upper endoscopy. Between 50% and 75% of all patients diagnosed with GERD will have abnormalities in the mucous lining of the esophagus, usually erosion, tissue fragility, and erythema. Upper endoscopy is also used to document esophageal strictures and Barrett’s esophagus. Patients with such symptoms as hematemesis (vomiting blood), iron deficiency anemia, guaiac-positive stools, or dysphagia should have an upper endoscopy. To perform this study, the doctor passes an endoscope, which is a thin instrument with a light source attached, through the patient’s mouth into the esophagus. The endoscope allows the doctor to visualize the mucosal lining of the esophagus, the junction between the esophagus and the stomach, and the lining of the upper portion of the stomach. He or she can take biopsy specimens at the same time.

Ambulatory esophageal pH monitoring
This test provides information concerning the frequency and duration of episodes of acid reflux. It can also provide information related to the timing of these episodes. Ambulatory esophageal monitoring is the standard procedure for documenting abnormal acid reflux; however, it is not necessary for most persons with GERD as they can be adequately diagnosed on the basis of their history or by performing an upper endoscopy. To perform this test, the doctor passes a tiny catheter (about 2 mm wide) with two electrodes through the patient’s nose and throat. One electrode is positioned about about 2 in (5 cm) above the esophageal sphincter. The other electrode is positioned just below the esophageal sphincter. Data related to pH level are obtained every four seconds for 24 hours. The patient is instructed to keep a diary of his or her symptoms, and to record coughing episodes, meal times, bedtime, and time of rising. The electrodes are removed after 24 hours and the patients’ diary is reviewed.

Barium esophagography
In a barium esophagograph, the patient is given a solution of water and barium sulfate to drink slowly. Xrays are taken at intervals as the patient swallows the mixture; the images are analyzed for signs of reflux, inflammation, dysmotility, strictures, and other abnormalities. Barium esophagography provides important information about a number of disorders involving esophageal function, including cricopharyngeal achalasia (a swallowing disorder of the throat); decreased or reverse peristalsis; and hiatal hernia.

Esophageal manometry
Esophageal manometry is a useful test for patients who may need surgery because it provides data about esophageal peristalsis and the minimum closing pressure of the esophageal sphincter by measuring the pressure within the esophagus. To perform this test, the doctor passes a thin soft tube through the patient’s nose or mouth. When the patient swallows, the tip of the tube enters the esophagus and is positioned at the desired location. The patient then swallows air or water while a technician records the pressure at the tip of the tube.

Preparation
Upper endoscopy
Persons are instructed not to eat or drink for 6 hours before an upper endoscopy. A mild sedative may be given to patients who are unusually nervous.

Ambulatory esophageal pH monitoring
No special preparations are needed for this test. A short-acting anesthetic spray is sometimes used to relieve any discomfort associated with placing the electrodes.
Barium esophagography
The patient should not eat or drink for 6 hours before a barium test.

Esophageal manometry
The patient should take nothing by mouth for 8 hours prior to the test. The doctor may use an anesthetic spray to reduce the throat irritation caused by the manometry tube.