HOW IS A DIGESTIVE DISORDER DIAGNOSED?
In order to reach a diagnosis for digestive disorders, a thorough and accurate medical history will be taken by your physician, noting the symptoms you have experienced and any other pertinent information. A physical examination is also done to help assess the problem more completely.
Some patients may need to undergo a more extensive diagnostic evaluation, which may include laboratory tests, imaging tests, endoscopic procedures, and other procedures. These tests may include any, or a combination of, the following:
- Fecal occult blood test
A fecal occult blood test checks for hidden (occult) blood in the stool. It involves placing a very small amount of stool on a special card, which is then tested in the physician's office or sent to a laboratory.
- Stool culture
A stool culture checks for the presence of abnormal bacteria in the digestive tract that may cause diarrhea and other problems. A small sample of stool is collected and sent to a laboratory by your physician's office. In two or three days, the test will show whether abnormal bacteria are present.
Ultrasound is a diagnostic imaging technique that uses high-frequency sound waves and a computer to create images of blood vessels, tissues, and organs. An ultrasound is used to view internal organs as they function, and to assess blood flow through various vessels. Gel is applied to the area of the body being studied, such as the abdomen, and a wand called a transducer is placed on the skin. The transducer sends sound waves into the body that bounce off organs and return to the ultrasound machine, producing an image on the monitor. A picture or video tape of the test is also made so it can be reviewed in the future.
- Computed tomography scan (CT or CAT scan)
This diagnostic imaging procedure uses a combination of x-rays and computer technology to produce cross-sectional images (often called slices), both horizontally and vertically, of the body. A CT scan shows detailed images of any part of the body, including the bones, muscles, fat, and organs. CT scans are more detailed than general x-rays.
- Magnetic resonance imaging (MRI)
MRI is a diagnostic procedure that uses a combination of large magnets, radiofrequencies, and a computer to produce detailed images of organs and structures within the body. The patient lies on a bed that moves into the cylindrical MRI machine. The machine takes a series of pictures of the inside of the body using a magnetic field and radio waves. The computer enhances the pictures produced. The test is painless, and does not involve exposure to radiation. Because the MRI machine is like a tunnel, patients who are claustrophobic or unable to hold still during the test, may be given a sedative to help them relax. Metal objects cannot be present in the MRI room, so persons with pacemakers or metal clips or rods inside the body cannot have this test done. All jewelry must be removed before the procedure.
- Oropharyngeal motility (also called modified barium swallow) study
During this test, the patient is given small amounts of a liquid containing barium to drink using a bottle, spoon, or cup. Barium is a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray. A series of x-rays are taken to evaluate what happens as the liquid is swallowed.
- Upper GI (gastrointestinal) series and small bowel follow-through series
An upper GI series is a diagnostic test that examines the organs of the upper part of the digestive system: the esophagus, stomach, duodenum (the first section of the small intestine), and small bowel. A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray) is swallowed. X-rays are then taken to evaluate the digestive organs.
- Lower GI (gastrointestinal) series (also called barium enema)
A lower GI series is a procedure that examines the rectum, the large intestine, and the lower part of the small intestine. A fluid called barium (a metallic, chemical, chalky, liquid used to coat the inside of organs so that they will show up on an x-ray) is placed into the rectum as an enema. An x-ray of the abdomen shows strictures (narrowed areas), obstructions (blockages), and other problems.
- Radioisotope gastric-emptying scan
During this test, the patient eats food containing a radioisotope, which is a slightly radioactive substance that will show up on a scan that is done while the patient lies under a machine. The dosage of radiation from the radioisotope is very small and not harmful, but it allows the radiologist to see the food in the stomach and observe how quickly it leaves the stomach.
- Colorectal transit study
This test shows how well food moves through the colon. The patient swallows capsules containing small markers which are visible on x-ray. The patient follows a high-fiber diet during the course of the test, and the movement of the markers through the colon is monitored with abdominal x-rays taken several times three to seven days after the capsule is swallowed.
Defecography is an x-ray of the anorectal area that evaluates completeness of stool elimination, identifies anorectal abnormalities, and evaluates rectal muscle contractions and relaxation. During the examination, the patient's rectum is filled with a soft paste that is the same consistency as stool. The patient then sits on the toilet that has been positioned inside an x-ray machine, and squeezes and relaxes the anus to expel the solution. The physician studies the x-rays to determine if anorectal problems occurred while the patient was emptying the paste from the rectum.
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- Esophageal manometry
This test helps determine the function of the muscles in the esophagus. It is useful in evaluating swallowing abnormalities and other esophageal symptoms. It is frequently used to understand how the esophagus is performing before a patient undergoes antireflux surgery for gastroesophageal reflux disease. A small tube is guided into the nostril, then passed into the throat, and finally into the esophagus. The patient is asked to swallow sips of water to allow assessment of esophageal muscle function. The type of esophageal manometry performed (high resolution manometry) was designed and developed at our institution in the 1990s, and is the standard form of esophageal manometry in use today.
- 24-hour catheter-based pH monitoring
An esophageal pH monitor measures the levels of acid inside of the esophagus. It is helpful in evaluating gastroesophageal reflux disease (GERD). A thin, plastic tube is placed into a nostril, guided down the throat, and then into the esophagus. The tube stops just above the lower esophageal sphincter, which is at the connection between the esophagus and the stomach. The distance to the lower esophageal sphincter is measured with an esophageal manometry study as described above. At the end of the tube that has been placed inside the esophagus is a sensor that measures pH, or acidity. The other end of the tube outside the body is connected to a monitor that records the pH levels for a 24 - 48 hour period. Normal activity is encouraged during the study, and the patient keeps a diary of symptoms experienced, or activity that might be suspicious for reflux, such as gagging or coughing, and any food that is eaten. Patients are also often asked to keep a record of the time, type, and amount of food eaten. The patient presses buttons on the pH receiver to indicate symptoms. The pH readings are evaluated and compared to the patient's activity for that time period.
- 48-hour wireless pH monitoring
This test uses a tiny pH probe that is attached to the wall of the esophagus. The probe communicates with a receiver that patients wear on their belt. This test is like the 24-hour catheter-based test because the patient is asked to participate in normal activity and to keep a diary of symptoms. The patient is also asked to press buttons on a receiver to note symptoms, so that symptom-reflux correlation can be assessed when the study is analyzed. This technique is more comfortable for the patient than the catheter-based test, but only provides acid recordings from one site in the esophagus. An endoscopy is typically required to measure the distance to the junction between the esophagus and the stomach.
- 24-hour catheter-based pH-impedance monitoring
An esophageal pH-impedance monitor measures not just the acidity inside of the esophagus but can also determine all reflux events even if the reflux is not acidic. This test is similar to the 24 hour catheter-based pH monitoring test. This test is particularly useful in determining if symptoms that persist on medication therapy for reflux disease are related to ongoing reflux events. The patient is encouraged to maintain normal activity levels during the study and to keep a diary of symptoms of activity that might seem like reflux, such as gagging or coughing, and any food that is eaten. The patient may also be asked to keep a record of the time, type, and amount of food eaten. The patient presses buttons on a receiver to record symptoms. This test produces readings that are evaluated and compared to the patient's activity for that time period.
- Anorectal manometry
This test helps determine the strength of the muscles in the rectum and anus. These muscles normally tighten to hold in a bowel movement and relax when a bowel movement is passed. Anorectal manometry is helpful in evaluating anorectal sphincter dysfunction and obstructed defecation, among other problems. A small tube is placed into the rectum to measure the pressures exerted by the sphincter muscles that ring the canal. High-resolution anorectal manometry (similar to high-resolution esophageal manometry) was developed in our institution, and is consistently used for testing here.
- "Smart pill" test
This test measures the amount of time it takes for a number of gastrointestinal processes to occur, including stomach emptying time, small bowel transit time and colon transit time. The device used in this test is the size of a pill (smart pill). The device is swallowed by the patient. Once the pill is swallowed, it can measure pressures, acidity and temperature continuously, and transmits these measurements to a device that the patient wears on their belt. The combination of pressure and acidity can determine when the capsule moves out of the stomach into the small intestine and from the small intestine to the large intestine. A drop in temperature is seen when the patient passes the capsule with a bowel movement. This test is relatively new, and is useful to measure delayed gastric emptying and delayed intestinal transit.
- Urea breath test for Helicobacter pylori
This test is used to detect the bacteria called Helicobacter pylori, or H. pylori, which can cause ulcers in the stomach and the duodenum—the first part of the small intestine. During the test, the patient swallows a radio-labeled meal that reacts with the body. The patient’s breath is then measured for the amount of carbon dioxide that is exhaled. This measurement indicates the presence of H. pylori.
- Secretin stimulation study
This test is useful to determine if there is uncontrolled production of a hormone named gastrin. Gastrin levels are checked in patients with recurrent ulcers and sometimes in patients with severe diarrhea where no other cause is found. If gastrin is found to be elevated, levels are rechecked after another hormone called secretin is given intravenously. The gastrin level increases significantly if there is uncontrolled production of the hormone, but decreases or remains the same in other instances.
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To make an appointment with a Washington University gastroenterologist or hepatologist at Barnes-Jewish Hospital, call 314-TOP-DOCS (314-867-3627) or toll-free 866-867-3627.