Gastroesophageal Reflux Scan
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.
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.
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.
Barrett’s esophagus— An abnormal condition of the esophagus in which normal mucous cells are replaced by changed cells. This condition is often a prelude to cancer.
Clearance— The process of removing a substance or obstruction from the body.
Dysphagia— Difficulty in swallowing.
Endoscope— An instrument with a light source attached that allows the doctor to examine the inside of the digestive tract or other hollow organ.
Erosion— A gradual breakdown or ulceration of the uppermost layer of tissue lining the esophagus or stomach.
Esophageal varices — Varicose veins at the lowermost portion of the esophagus. Esophageal varices are easily injured, and bleeding from them is often difficult to stop.
Esophagus— The muscular tube that connects the mouth to the stomach.
Heartburn— A sensation of warmth or burning behind the breastbone, rising upward toward the neck. It is often caused by stomach acid flowing upward from the stomach into the esophagus.
Hematemesis— Vomit that contains blood, usually seen as black specks in the vomitus.
Incompetent— In a medical context, insufficient. An incompetent sphincter is one that is not closing properly.
pH— A measure of acidity; technically, a measure of hydrogen ion concentration. The stomach contents are more acidic than the tissues of the esophagus.
Raynaud’s disease— A disease of the arteries in hands or feet.
Reflux— Backflow, also called regurgitation.
Sjogren’s syndrome— An autoimmune disorder characterized by dryness of the eyes, nose, mouth, and other areas covered by mucous membranes.
Sphincter— A circular band of muscle fibers that constricts or closes a passageway in the body. The esophagus has sphincters at its upper and lower ends.
Visualize— To achieve a complete view of a body structure or area.
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 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 Barret’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 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.
In a barium esophagograph, the patient is given a solution of water and barium sulfate to drink slowly. X rays 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 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.
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.
The patient should not eat or drink for 6 hours before a barium test.
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.
After an upper endoscopy, a friend or relative should drive the patient home because of the lingering effects of the sedative.
Other esophageal scans
There are no special aftercare instructions for patients who have had ambulatory esophageal pH monitoring, barium esophagography, or esophageal manometry.
Patients sometimes feel as if they are choking as the doctor passes the endoscope down the throat. This feeling is uncommon, however, if the patient has been given a sedative.
Ambulatory esophageal pH monitoring
There are no common complications following this test.
Constipation after the test is an infrequent side effect that is treated by giving the patient a laxative.
Complications following this test are very rare.
An upper endoscopy documents the condition of the mucous lining of the lower esophagus and upper stomach, thus allowing the doctor to evaluate the progression of GERD.
Ambulatory esophageal pH monitoring
Measurements of pH are used to evaluate the degree of GERD.
Barium esophagography can detect many structural and functional abnormalities, including the presence of acid reflux, inflammation, tissue masses, or strictures in the esophagus.
This test documents the ability of the esophageal sphincter to close adequately and keep the contents of the stomach from flowing backward into the esophagus.
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American College of Gastroenterology. 4900 B South 31st Street, Arlington, VA, 22206. (703) 820-7400. www.acg.gi.org.
American College of Radiology. 1891 Preston White Drive, Reston, VA, 20191. (703) 648-8900. www.acr.org.
American Osteopathic College of Radiology. 119 East Second St., Milan, MO 63556. (660) 265-4011. www.aocr.org.
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L. Fleming Fallon, Jr., MD, DrPH
Lee A. Shratter, M.D.