Section 9. Digestive Disorders

Chapter 119. Symptoms and Diagnosis of Digestive Disorders

Topics: Introduction | Symptoms | Diagnosis

Diagnosis

Usually, a doctor can determine whether a person has a digestive disorder on the basis of a medical history and a physical examination. The doctor can then select appropriate diagnostic 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. The person is encouraged to describe symptoms in his own terms. The doctor can then ask specific questions to gain additional information. For example, in speaking with a person with abdominal pain, the doctor might first ask, "What is the pain like?" This question might be followed by questions like, "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 (distension) of the abdominal wall that might accompany abnormal growth or enlargement of a particular part of the digestive tract. 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.

Psychologic Evaluation

Because the digestive system and the brain are so highly interactive (see Section 9, Chapter 118), psychologic evaluation is sometimes needed in the evaluation of digestive problems. In such cases, doctors are not implying that the digestive problems are imagined or made up. Rather, they may be the result of anxiety, depression, or other treatable mental disorders, as appears to be true for as many as 50% of people with a digestive disorder.

Diagnostic Procedures

On the basis of the findings of the medical history, physical examination, and, if applicable, psychologic evaluation, doctors choose the appropriate diagnostic 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, 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 do not require any preparation at all.

Although diagnostic tests can be very accurate, they can also be quite expensive and, in rare cases, can pierce (perforate) the digestive tract or cause bleeding or injury.

Endoscopy

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 most 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 medication intravenously to prevent discomfort.

See the figure Viewing the Digestive Tract With an Endoscope.

Endoscopes range in diameter from about ¼ inch to about ½ inch and range in length from about 1 foot to about 5 feet. 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 lining of the digestive tract. 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. These samples can then be evaluated for evidence of 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 of the endoscope can be used to inject drugs into dilated veins in the esophagus and stop their bleeding.

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 before the procedure 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 only irritation of the digestive tract lining and a little bleeding.

Laparoscopy

Laparoscopy is an examination of the abdominal cavity using an endoscope. Laparoscopy is usually performed 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 reparative surgery. Complications include bleeding, infection, and perforation of the digestive tract.

X-ray Studies

X-rays often are used to evaluate digestive problems. Standard x-rays of the abdomen do not require any special preparation. These x-rays generally are used to 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. Or, 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 if their contractions are normal, and tell whether food is getting blocked in the digestive tract. 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 given as an enema is eventually excreted in the stool, making the stool chalky white. Because barium can cause significant constipation, the doctor tries to make sure the barium is eliminated quickly after the studies. A gentle laxative can speed up the elimination of barium.

Ultrasound Scanning

Ultrasound scanning uses sound waves to produce pictures of internal organs. The examiner (a doctor or technician) usually performs an ultrasound scan by pressing a small probe against the person's abdominal wall. Sound waves are directed to various parts of the abdomen by moving the probe. The pictures are then displayed on a video screen and recorded on video film. 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. It can show the presence of fluid as well. Ultrasound scanning with a probe on the abdominal wall is not a good method for examining the lining of the digestive tract, so it is less commonly used to look for tumors and causes of bleeding in the stomach, small intestine, or large intestine. Endoscopic ultrasound, a newer procedure, shows the lining of the digestive tract 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) and magnetic resonance imaging (MRI) allow the doctor to view the abdomen at many different levels (cross-sections).

For either CT or MRI, the person is usually required to fast on the morning of the test. A radiopaque dye, which is visible on x-rays, is given intravenously before CT scanning; a paramagnetic contrast agent is given intravenously before an MRI. The person lies either on a table or in a tube-shaped device, and the machine slowly passes over the areas of interest.

In a CT scan, the machine gives off x-rays. In an MRI scan, the responses of the body's tissues to being in a magnetic field allow the machine to develop images of the underlying organs. Both of these tests require the person to lie still during the imaging process and may involve lying in a tube-like structure. People with fear of being in enclosed spaces (claustrophobia) may have difficulty with the test, although open scanners are becoming increasingly available. Also, some people may have a reaction to the dye used for the scan, including hives, shortness of breath, and rarely, dangerous lowering of the blood pressure.

CT and MRI scans are good for looking at 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 the path or size of blood vessels can be detected as well. Inflammation, such as of the appendix (appendicitis) or diverticula (diverticulitis), is usually evident. Sometimes, these tests are used to help guide radiologic or surgical procedures.

Paracentesis

Paracentesis is the insertion of a needle into the abdominal cavity and the removal of fluid. Normally, the abdominal cavity outside of the digestive tract 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 diagnosing a condition (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, generally 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. When bleeding is profuse, a person can vomit blood (hematemesis), pass bright red blood in the stool (hematochezia), or pass black, tarry stool (melena). Amounts of blood too small to be seen or to change the appearance of stool can be detected chemically, and 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 obtains 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 color of the sample will change if blood is present. Alternatively, the person can take home a kit containing the impregnated 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 through the nose or mouth into the stomach or small intestine. This procedure may be used for diagnostic or treatment purposes. Intubation may cause gagging and nausea in some people. The tube size varies according to the purpose.

Nasogastric intubation (passage of a tube through the nose into the stomach) 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 by this route. Also, passage of a tube through the nose is less irritating and is less likely to trigger coughing. By inserting a nasogastric tube, doctors can determine whether the stomach contains blood, or they can analyze the stomach's secretions for acidity, enzymes, and other characteristics. In poisoning victims, samples of the stomach fluid can be analyzed to identify the poison. In some cases, the tube is left in place, so that more 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 administered 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 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

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 large intestine to determine the adequacy of muscle contractions, which are needed to move stool forward and to eventually result in a bowel movement.

An esophageal pH test (a test that measures acidity in the esophagus) can be performed during esophageal manometry. The test is used to determine if a person has backflow of stomach acid into the esophagus (gastroesophageal reflux). One or more measurements may be taken.