At a Glance
  • Often the diagnosis of a functional GI disorder can be made with few or no tests.
  • Sometimes tests are needed to rule out another disease.
  • Usually some preparation is needed before the test may be done.
  • Correct preparation for a test helps make it easier and more effective.
  • Knowing what to expect will help you feel more at ease.

In many cases, doctors can make a diagnosis of a functional gastrointestinal disorder after a careful history and examination. Often, however, there is a structural disease that must be excluded by tests that probe the gastrointestinal tract.

In dyspepsia, for example, upper abdominal distress may be due to a peptic ulcer in the stomach or duodenum, and an endoscopy may be required to rule out such lesions. In the case of irritable bowel syndrome (IBS) or constipation, there may be an alarm feature, such as blood in the stool or a family history of colorectal cancer that prompts a doctor to order a colonoscopy, sigmoidoscopy, or barium enema.

For these and other gastrointestinal investigations, some preparation is required. If you have to have one of these tests, it may help to know why the preparation is necessary and how to make it effective and less stressful.

General principles

When preparing yourself for an invasive gut procedure, it is well to keep in mind that the cleanliness and emptiness of the part to be examined is vital to success. If the examiner cannot see the colon wall because of a residue of stool, or the stomach because of a last-minute snack, there is a risk that he or she may fail to identify an important abnormality. Perforation of the colon is very rare, but will contaminate the abdominal cavity less if the organ is empty.

Often, during such a procedure, it is necessary to biopsy, cauterize, or remove a lesion, and that risks bleeding. It is therefore important to tell the doctors and nurses involved in the procedure what drugs you are taking, especially blood thinners (anticoagulants) and aspirin. The doctor may suspend these blood thinning drugs for the procedure. If your doctor agrees, aspirin (ASA, acetylsalicylic acid) should be stopped a week prior to the procedure in order to ensure that the blood platelets (small cells important in blood clotting) have returned to normal.

Iron may blacken the stool, reducing visibility. Therefore, iron-containing medication or diet supplements should be stopped 72 hours prior to a colonoscopy.

Sedation – Since some procedures require sedation, you must inform your doctor of any drug sensitivities, cardiovascular disease, or previous bad experiences with sedation. If sedation is to be given, or even possibly given, you should not drive from the clinic, but arrange to be picked up by a responsible party. Most facilities do not permit a cab trip home without a companion.

If you have diabetes, kidney failure, or other chronic disease, the doctor should be asked for special instructions regarding diet and medication.

There are many local variations in how, when, and what sedation is employed. For an endoscopy (a procedure that involves insertion, through the mouth or anus, of a thin, flexible tube used to look into the esophagus, stomach, duodenum, small intestine, colon, or rectum) an intravenous line usually is set up by the nurse after you arrive at the clinic.

The drugs are administered by injection into that line immediately before the test. There are many sedatives and relaxants available for this purpose. For the most part, the medications are safe and effective, but they require a period of recovery after their administration. You are not put to sleep since you need to be conscious and cooperative throughout. (This is called conscious sedation.) Tests of gut motility or function often require even more cooperation, and sedation is neither required nor advisable.

Sedation lessens any anxiety associated with the test. It may be given with a pain killer. The nurse or doctor will explain the possible adverse reactions particular to the drug or drugs used. Tolerances differ and too your reaction will be monitored. A device clipped to a finger permits the nurse to monitor your heart rate and blood oxygen saturation during the test.

The medications cause temporary forgetfulness; sometimes, examinees even forget having had the test. You may not even be able to remember or fully understand the test results if they are presented to you after the test. It is wise to arrange a follow-up meeting with the doctor to be sure that all the implications of these results are clearly addressed.

Local Anesthesia – Before starting a procedure that involves the insertion of an instrument into the esophagus and beyond, the nurse may apply a topical anesthetic to your throat. This is to help you swallow the instrument without gagging. The drug used is usually xylocaine and it may be applied as a spray, or as a gel that you swallow. It has a bad taste, and attempts to flavor it have had little success.

Consent – As with all medical procedures, you will be asked to sign a consent form that certifies that you understand the risks and benefits of the procedure, and that your doctor has explained them to you.

The consent procedure is an opportunity for you to ask questions. Normally, intestinal examinations are very safe. However, perforations of the organ may occur, especially when the area being examined is diseased, or if removal of a tissue sample (biopsy), cauterization, or removal of a polyp or foreign body is involved. This rare complication may require emergency surgery.

Before leaving the doctor’s office where the procedure has been arranged, be certain you understand everything about the procedure and its preparation. Failure to do this invites fear and misunderstanding, and it is often difficult and less satisfactory to correct these later by phone. As you sign the consent form you should understand with what, when, where, and why the procedure is being done, and if not satisfied, you should decline the test or seek a second opinion.

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