Usually, a doctor can determine whether a person has a digestive disorder based on a medical history and a physical examination. The doctor can then select appropriate procedures that help to confirm the diagnosis, determine the extent and severity of the disorder, and aid in planning treatment.
Medical History and Physical Examination
A doctor identifies symptoms by interviewing a person to obtain the medical history. Doctors ask specific questions to gain additional information. For example, in speaking with a person who has abdominal pain, the doctor might first ask, “What is the pain like?” This question might be followed by questions such as, “Does the pain get better after you eat?” or “Does the pain get worse when you bend over?”
During the physical examination, the doctor notes the person's weight and overall appearance, which may be indicators of digestive disorders. Although the doctor may examine the entire body, emphasis is placed on examining the abdomen, anus, and rectum.
First, the doctor observes the abdomen from different angles, looking for expansion (distention) of the abdominal wall that might accompany abnormal growth or enlargement of an organ. A stethoscope is placed on the abdomen, through which the doctor listens for sounds that normally accompany the movement of material through the intestines and for any abnormal sounds. The doctor feels for tenderness and any abnormal masses or enlarged organs. Pain that is caused by gentle pressure on the abdomen and that is relieved when the pressure is released (rebound tenderness) usually indicates inflammation and sometimes infection of the lining of the abdominal cavity (peritonitis).
The anus and rectum are examined with a gloved finger, and a small sample of stool is sometimes tested for hidden (occult) blood. In women, a pelvic examination often helps distinguish digestive problems from gynecologic ones.
Because the digestive system and the brain are highly interactive, a psychologic evaluation is sometimes needed in the evaluation of digestive problems. In such cases, doctors are not implying that the digestive problems are made up or imagined. Rather, the digestive problems may be the result of anxiety, depression, or other treatable mental disorders, which seems to be true for as many as 50% of people with symptoms of a digestive disorder.
Based on the findings of the medical history, physical examination, and, if applicable, psychologic evaluation, doctors choose appropriate tests. Tests performed on the digestive system make use of endoscopes (flexible tubes that doctors use to view internal structures and to obtain tissue samples from inside the body), x-rays, ultrasound scans, tiny amounts of radioactive materials, capsule endoscopy, and chemical measurements. These tests can help a doctor locate, diagnose, and sometimes treat a problem. Some tests require the digestive system to be cleared of stool, some require 8 to 12 hours of fasting, and others require no preparation.
Although diagnostic tests can be very accurate, they can also be quite expensive and, in rare cases, can cause bleeding or injury.
Endoscopy is an examination of internal structures using a flexible viewing tube (endoscope). When passed through the mouth, an endoscope can be used to examine the esophagus (esophagoscopy), the stomach (gastroscopy), and part of the small intestine (upper gastrointestinal endoscopy). When passed through the anus, an endoscope can be used to examine the rectum (anoscopy); the lower portion of the large intestine, the rectum, and the anus (sigmoidoscopy); and the entire large intestine, the rectum, and the anus (colonoscopy). For procedures other than anoscopy and sigmoidoscopy, the person is given drugs intravenously to prevent discomfort.
Endoscopes range in diameter from about ¼ inch (a bit more than ½ centimeter) to about ½ inch (1¼ centimeters) and range in length from about 1 foot (about 30½ centimeters) to about 6 feet (almost 2 meters). The choice of endoscope depends on which part of the digestive tract is to be examined. The endoscope is flexible and provides both a lighting source and a small camera, which allows doctors to get a good view of the tract lining. The doctor can see areas of irritation, ulcers, inflammation, and abnormal tissue growth.
Many endoscopes are equipped with a small clipper with which tissue samples can be taken (endoscopic biopsy). These samples can then be evaluated for inflammation, infection, or cancer. Because the lining and the inner layers of the walls of the digestive tract do not have nerves that sense pain (with the exception of the lower part of the anus), this procedure is painless.
Endoscopes can also be used for treatment. A doctor can pass different types of instruments through a small channel in the endoscope. An electric probe at the tip of the endoscope can be used to destroy abnormal tissue, to remove small growths, or to close off a blood vessel. A needle at the tip can be used to inject drugs into dilated veins in the esophagus and stop their bleeding. A laser mounted at the end can be used to destroy abnormal tissue.
Before having an endoscope passed through the mouth, a person usually must avoid food for several hours. Food in the stomach can obstruct the doctor's view and might be vomited up during the procedure. Before having an endoscope passed into the rectum and colon, a person usually takes laxatives and is sometimes given enemas to clear out any stool. In addition, the person must avoid food for several hours because it might be vomited up and because it would reduce the effectiveness of the laxatives and enemas.
Complications from endoscopy are relatively rare. Although endoscopes can injure or even perforate the digestive tract, they more commonly cause irritation of the tract lining and a little bleeding.
Capsule endoscopy is a procedure in which the person swallows a battery-powered capsule. The capsule contains one or two small cameras, a light, and a transmitter. Images of the lining of the intestines are transmitted to a receiver worn on the person's belt or in a cloth pouch. Thousands of pictures are taken. This technology is especially good at finding problems on the inner surface of the small intestine, which is an area that is difficult to evaluate with an endoscope.
Laparoscopy is an examination of the abdominal cavity using an endoscope, usually with the person under general anesthesia. After the appropriate area of the skin is washed with an antiseptic, a small incision is made, usually in the navel. Then an endoscope is passed into the abdominal cavity. A doctor can look for tumors or other abnormalities, examine virtually any organ in the abdominal cavity, obtain tissue samples, and even do surgery. Complications include bleeding, infection, and perforation.
X-rays often are used to evaluate digestive problems. Standard x-rays do not require any special preparation (see Plain X-Rays). These x-rays usually can show an obstruction or paralysis of the digestive tract or abnormal air patterns in the abdominal cavity. Standard x-rays can also show enlargement of the liver, kidneys, and spleen.
Barium studies often provide more information. X-rays are taken after a person swallows barium in a flavored liquid mixture or as barium-coated food. The barium looks white on x-rays and outlines the digestive tract, showing the contours and lining of the esophagus, stomach, and small intestine. Barium collects in abnormal areas, showing ulcers, tumors, obstructions, erosions, and enlarged, dilated esophageal veins.
X-rays may be taken at intervals to determine where the barium is. In a continuous x-ray technique called fluoroscopy, the barium is observed as it moves through the digestive tract. With this technique, doctors can see how the esophagus and stomach function, determine whether their contractions are normal, and tell whether food is getting blocked. The doctor may film this process for later review.
Barium also can be given in an enema to outline the lower part of the large intestine. Then, x-rays can show polyps, tumors, or other structural abnormalities. This procedure may cause crampy pain, producing slight to moderate discomfort.
Barium taken by mouth or as an enema is eventually excreted in the stool, making the stool chalky white. Because barium can cause significant constipation, the doctor may give a gentle laxative to speed up the elimination of barium.
Ultrasound scanning uses sound waves to produce pictures of internal organs (see Ultrasonography). An ultrasound scan can show the size and shape of many organs, such as the liver and pancreas, and can also show abnormal areas within them, such as cysts and some tumors. It can also show fluid in the abdominal cavity (ascites). Ultrasound scanning with a probe on the abdominal wall is not a good method for examining the lining of the digestive tract. Endoscopic ultrasound, however, shows the lining more clearly because the probe is placed on the tip of an endoscope.
An ultrasound scan is painless and poses no risk of complications. Endoscopic ultrasound poses the same risk of complications as endoscopy.
Computed Tomography and Magnetic Resonance Imaging
Computed tomography (CT---see Computed Tomography) and magnetic resonance imaging (MRI---see Magnetic Resonance Imaging) scans are good tools for assessing the size and location of abdominal organs. Additionally, growths such as cancerous (malignant) or noncancerous (benign) tumors are often detected by these tests. Changes in blood vessels can be detected as well. Inflammation, such as that of the appendix (appendicitis) or diverticula (diverticulitis), is usually evident. Sometimes, these tests are used to help guide radiologic or surgical procedures.
Paracentesis is the insertion of a needle into the abdominal cavity for the removal of fluid. Normally, the abdominal cavity contains only a small amount of fluid. However, fluid can accumulate in certain circumstances, such as when a person has liver disease, heart failure, a ruptured stomach or intestine, cancer, or a ruptured spleen. A doctor may use paracentesis to aid in diagnosis (for example, to obtain a fluid sample for analysis) or as part of treatment (for example, to remove excess fluid).
Before paracentesis, a physical examination, sometimes accompanied by an ultrasound scan, is performed to confirm that the abdominal cavity contains excess fluid. Next, an area of the skin, usually just below the navel, is washed with an antiseptic solution and numbed with a small amount of anesthetic. A doctor then pushes a needle attached to a syringe through the skin and muscles of the abdominal wall and into the area of fluid accumulation. A small amount of fluid may be removed for laboratory testing, or up to several quarts may be removed to relieve distention. Complications include perforation of the digestive tract and bleeding.
Occult Blood Tests
Bleeding in the digestive system can be caused by something as insignificant as a little irritation or as serious as cancer. Amounts of blood too small to be seen or to change the appearance of stool can be detected chemically. The detection of such small amounts may provide early clues to the presence of ulcers, cancers, and other abnormalities.
During a rectal examination, the doctor may obtain a small amount of stool on a gloved finger. This sample is placed on a piece of filter paper impregnated with a chemical (guaiac). After another chemical is added, the sample will change color if blood is present. More preferably, the person can take home a kit containing the filter papers. The person places samples of stool from about three different bowel movements on the filter papers, which are then mailed in special containers back to the doctor for testing. If blood is detected, further examinations are needed to determine the source.
Intubation of the Digestive Tract
Intubation of the digestive tract is the process of passing a small, flexible plastic tube (nasogastric tube) through the nose or mouth into the stomach or small intestine. This procedure may be used for diagnostic or treatment purposes. Intubation typically causes gagging and nausea, so a numbing spray is usually applied into the nose and back of the throat. The tube size varies according to the purpose.
Nasogastric intubation can be used to obtain a sample of stomach fluid. The tube is passed through the nose rather than through the mouth, primarily because the tube can be more easily guided to the esophagus. Also, passage of a tube through the nose is less irritating and less likely to trigger coughing. Doctors can determine whether the stomach contains blood, or they can analyze the stomach's secretions for acidity, enzymes, and other characteristics. In people with poisoning, samples of the stomach fluid can be analyzed to identify the poison. In some cases, the tube is left in place so that samples can be obtained over several hours.
Nasogastric intubation may also be used to treat certain conditions. For example, poisons can be pumped out or neutralized with activated charcoal, or liquid food can be given to people who cannot swallow.
Sometimes nasogastric intubation is used to continuously remove the contents of the stomach. The end of the tube is usually attached to a suction device, which removes gas and fluid from the stomach. This helps relieve pressure when the digestive system is blocked or otherwise not functioning properly. This type of tube is often used after abdominal surgery until the digestive system can resume its normal function.
In a procedure called 24-hour pH testing, a tube is placed through the nose into the esophagus, where it sits for 24 hours. The tube frequently samples the fluid of the esophagus, allowing detection of stomach acid that comes up into the chest (esophageal reflux). This test allows the doctors to measure the severity and frequency of reflux.
In nasoenteric intubation, a longer tube is passed through the nose, through the stomach, and into the small intestine. This procedure can be used to remove a sample of intestinal contents, continuously remove fluids, or provide food.
Manometry is a test in which a tube with pressure gauges along its surface is placed in the esophagus. Using this device (manometer), a doctor can determine whether contractions of the esophagus can propel food normally. Sometimes a doctor uses a similar device to measure pressure in the anal sphincter to determine whether the muscle opens normally.
Last full review/revision May 2007 by Nicholas J. Shaheen, MD, MPH