MedicineNet.com
About Us | Privacy Policy | Site Map
November 22, 2009
MedicineNet home Picture Slideshows Diseases and conditions Symptoms and signs Procedures and tests Medications Health and Living Picture Image Collection MedTerms medical dictionary
Font Size
A
A
A

Irritable Bowel Syndrome (cont.)

What are the complications of IBS?

The complications of functional diseases of the gastrointestinal tract are relatively limited. Since symptoms are most often provoked by eating, patients who alter their diets and reduce their intake of calories may lose weight. Fortunately, loss of weight is unusual in functional diseases, and it should suggest the presence of a non-functional disease. Symptoms that awaken patients from sleep also are more likely to be due to non-functional than functional diseases.

Most commonly, functional diseases interfere with the patients' comfort and their daily activities. For example, patients who suffer from morning diarrhea may not leave their home until the diarrhea stops. If the diarrhea is constant, they may go only to places where they know that a toilet is readily available. Patients who develop pain after eating may skip lunch. Very commonly, patients associate symptoms with specific foods, such as milk, fat, vegetables, etc. Whether or not these associations are real, these patients will restrict their diets accordingly. Milk is the food that is most commonly eliminated, often unnecessarily and to the detriment of adequate calcium intake. The interference with daily activities also can lead to problems with interpersonal relationships, especially with spouses. However, most patients with functional disease tend to just live with their symptoms and infrequently visit physicians for diagnosis and treatment.

How is IBS diagnosed?

The Rome Criteria

The symptoms of IBS are varied and inconsistent among patients. Moreover, there are no characteristically abnormal tests that can be used to diagnose IBS. All of this has made it difficult to define IBS and identify patients, especially for research studies. In 1999, a group of international investigators met in Rome for a second time (Rome II). There, they developed a set of criteria for symptoms to be used for diagnosing IBS.

The Rome II Criteria state that in order to be diagnosed with IBS, a patient should have suffered abdominal pain or discomfort for 12 weeks or more (not necessarily consecutive weeks) in the previous 12 months. The pain or discomfort should have two out of the three following features:

  • Relief with defecation
  • Onset associated with a change in the frequency of stool
  • Onset associated with a change in the form of stool

Other symptoms that are not essential, but support a diagnosis of IBS, are: (1) abnormal frequency of stools (more than 3/day or less than 3/week); (2) abnormal stool form (lumpy and hard, or loose and watery); (3) abnormal stool passage (straining, urgency, or feeling of incomplete evacuation); (4) passage of mucus; and (5) bloating (feeling of abdominal distention, or enlargement).

The Rome II criteria are rather specific for a diagnosis of IBS. In essence, they require the presence of prolonged abdominal pain or discomfort that is in some way related to an alteration in the pattern of bowel movements. Symptoms of dyspepsia (nausea or abdominal discomfort following meals), abdominal distention, and increased flatus (passing gas, or flatulence) alone do not fall within this definition. Nevertheless, many patients have these symptoms along with the symptoms of IBS. It is not clear if these patients have one problem (IBS) or more than one problem.

In 2006, the group of international investigators met for the third time in Rome and developed the Rome III criteria. A system of classification of gastrointestinal functional disorders came out of this meeting that was much more comprehensive and detailed than prior classifications. The definition of the subcategory, IBS, remained essentially unchanged, however, except for a requirement that the abdominal pain occur at a frequency of at least three times per month. The classification also clearly set apart from IBS three other functional bowel disorders - functional bloating, functional constipation, functional diarrhea, and unspecified functional bowel disorder.

Exclusion of non-functional gastrointestinal disease

As mentioned previously, the exclusion of non-functional disease in patients with suspected IBS is an important concern. There are many tests to exclude non-functional diseases. The primary issue, however, is to decide which tests are reasonable to perform. Since each case is individual, different tests may be reasonable for different patients. Nevertheless, there are some basic tests that are often performed to exclude non-functional gastrointestinal disease. These tests identify anatomic (structural) and histological (microscopic) diseases of the intestines. As always, a detailed history from the patient and a physical examination frequently will suggest the cause of symptoms. Routine screening blood tests often are performed looking for clues to unsuspected diseases. Examinations of stool also are a part of the evaluation since they may reveal infection, signs of inflammation, or blood and direct further diagnostic testing. Sensitive stool testing (antigen/antibody) for Giardia lamblia would be reasonable because this parasitic infection is common and can be acute or chronic. Some physicians do blood testing for celiac disease (sprue), but the value of doing this is unclear. Moreover, if an EGD is planned, biopsies of the duodenum usually will make the diagnosis of celiac disease. Both X-rays and endoscopies can identify anatomic diseases. Only endoscopies, however, can diagnose histological diseases because biopsies (taking samples of tissue) can be taken during the procedure. The X-ray tests include:

  • The esophagram and video-fluoroscopic swallowing study for examining the esophagus
  • The upper gastrointestinal series for examining the stomach and duodenum
  • The small bowel series for examining the small intestine
  • The barium enema for examining the colon and terminal ileum.

The endoscopic tests include:

  • Upper gastrointestinal endoscopy (esophago-gastro-duodenoscopy, or EGD) to examine the esophagus, stomach, and duodenum
  • Colonoscopy to examine the colon and terminal ileum
  • Endoscopy also is available to examine the small intestine, but this type of endoscopy is complex, not widely available, and of unproven value in suspected IBS.

For examination of the small intestine, there is also a capsule containing a tiny camera that can be swallowed. As the capsule travels through the intestines, it sends pictures of the inside of the intestines to an external recorder for later review. However, the capsule is not widely available and its value in IBS has not yet been proven.

X-rays are easier to perform and are less costly than endoscopies. The skills necessary to perform X-rays, however, are becoming rarer among radiologists because they are doing them less often. Therefore, the quality of the X-rays often is not as high as it used to be. As noted above, endoscopies have an advantage over X-rays because at the time of endoscopies, biopsies can be taken to diagnose or exclude histological diseases, something that X-rays cannot do.

Exclusion of non-intestinal disease

Patients with suspected IBS often undergo abdominal ultrasonography (US), computerized tomography (CT or CAT scans), or magnetic resonance imaging (MRI). These tests are used primarily to diagnose non-intestinal diseases. (Although these tests also may diagnose intestinal diseases, their value for this purpose is limited. As described above, X-ray and endoscopy are better tests.) It also is important to realize that US, CT, and MRI are powerful tests and will uncover abnormalities that are unrelated to IBS. The most common example is the finding of gallstones that, in fact, often cause no symptoms. This finding can cause a problem if the gallstones are assumed to be the source of the IBS symptoms. The problem is that surgical removal of the gallbladder with its gallstones (cholecystectomy) is unlikely to relieve the symptoms of IBS. (Cholecystectomy would be expected to relieve only the characteristic symptoms that gallstones sometimes can cause.) Tests to exclude non-intestinal diseases may be appropriate in specific situations, although certainly not in most patients.

Evaluation of intestinal transportation

If abnormal function of the muscles of the small intestine is suspected, tests to evaluate transportation through the small intestine or the colon (small intestinal and colonic transit studies, respectively) are available. These studies are done with either radioactive compounds or markers that can be seen on X-rays of the abdomen. It also is possible to pass catheters into the stomach and small intestine or the colon to determine if the muscles of these organs are working normally (antro-duodenal and colonic motility studies, respectively). Finally, constipation due to malfunction of the anal muscles can be diagnosed by ano-rectal motility studies.

Psychiatric illness

The possibility of psychiatric (psychosomatic) illness often arises in patients with IBS because the symptoms frequently are subjective, and no objective abnormalities can be identified. Psychiatric illness may complicate IBS, but it is unclear if psychiatric illness causes IBS. If there is a possibility of psychiatric illness, a psychiatric evaluation is appropriate.



Next: How is IBS treated? »

Irritable Bowel Syndrome - How Was Diagnosis Established

The MedicineNet physician editors ask:

How was the diagnosis of your irritable bowel syndrome established?

Comment submissions for this question have ended. Patient Discussions FAQs
See 20 Viewer Comments

View Comments


Printer-Friendly Format  |  Email to a Friend


Suggested Reading by Our Doctors
MedicineNet Doctors
  • amitriptyline. Elavil, Endep - Learn about amitriptyline ((Elavil, Endep) an antidepressant drug used to treat depression. Drug interactions and side effects are also included in the information.
  • CT Scan (Computerized Axial Tomography) - CT Scan (Computerized Axial Tomography, CAT scan) is a procedure that assists in diagnosing tumors, fractures, bony structures, and infections in the organs and tissues of the body.
  • Abdominal Pain - Learn about abdominal pain (pain in the stomach / abdomen) including causes, symptoms, how abdominal pain is diagnosed, and how abdominal pain is treated.

Latest Medical News


GI Disorders

Get the latest treatment options.


Are you Depressed? Take the Quiz

Your Guide to Symptoms & Signs: Pinpoint Your Pain












Health categories:

Slideshows | Diseases & Conditions | Symptoms & Signs | Procedures & Tests | Medications | Health & Living | News & Views | Medical Dictionary

Popular health centers:

Allergies | Arthritis | Cancer | Diabetes | Digestion | Healthy Kids | Heart | Men's Health | Mental Health | Women's Health | More...

Publications:

ePublications (PDFs) | XML News via RSS | Audio Podcasts | Email Newsletters

MedicineNet.com:

About Us | Privacy Policy | Site Map | WebMD® | Medscape® | eMedicine® | eMedicineHealth® | RxList®

This website is certified by Health On the Net Foundation. Click to verify. This site complies to the HONcode standard for trustworthy health information:
verify here.

©1996-2009 MedicineNet, Inc. All rights reserved. Notices and Legal Disclaimer.
MedicineNet does not provide medical advice, diagnosis or treatment. See additional information.