MedicineNet.com
About Us | Privacy Policy | Site Map
November 8, 2009
MedicineNet home Picture Slideshows Diseases and conditions Symptoms and signs Procedures and tests Medications Health and Living Health news and views MedTerms medical dictionary
Font Size
A
A
A

Irritable Bowel Syndrome (cont.)

What are IBS symptoms?

The primary purpose of the gastrointestinal tract is to digest (break down) and absorb (take into the blood stream) food. In order to fulfill this purpose, food must be ground, mixed, and transported through the intestines, where it is digested and absorbed. In addition, undigested and unabsorbed portions of the food must be eliminated from the body.

In functional diseases of the gastrointestinal tract, the grinding, mixing, digestion, and absorption functions are disturbed to only a minor degree. These functions are essentially maintained, perhaps because of a built-in over-capacity of the gastrointestinal tract to perform these functions. The most commonly affected function in these diseases is transportation. In the stomach and small intestine, the symptoms of slowed transportation are nausea, vomiting, abdominal bloating (the sensation of abdominal fullness), and abdominal distention (enlargement). The symptom of rapid transportation usually is diarrhea. The interpretation of symptoms, however, may be more complicated than this. For example, let's say that a person has abnormally rapid emptying of the stomach. The sensing of this rapid emptying by the intestinal sensory nerves normally brings about a motor nerve response to slow emptying of the stomach and transportation through the small intestine. Thus, rapid emptying of the stomach may give rise to symptoms of slowed transportation.

In the colon, abnormally slowed or rapid transportation results in constipation or diarrhea, respectively. In addition, there may be increased amounts of mucus coating the stool or a sense of incomplete evacuation after a bowel movement.

As discussed previously, normal sensations may be abnormally processed and perceived. Such an abnormality could result in abdominal bloating and pain. Abnormally processed sensations from the gastrointestinal organs also might lead to motor responses that cause symptoms of slowed or rapid transportation.

Slowed transportation of digesting food through the small intestine may be complicated, for example, by bacterial overgrowth. In bacterial overgrowth, gas-producing bacteria that are normally restricted to the colon move up into the small intestine. There, they are exposed to greater amounts of undigested food than in the colon, which they turn into gas. This formation of gas can aggravate bloating and/or abdominal distention and result in increased amounts of flatus (passing gas, or flatulence) and diarrhea.

The gastrointestinal tract has only a few ways of responding to diseases. Therefore, the symptoms often are similar regardless of whether the diseases are functional or non-functional. Thus, the symptoms of both functional and non-functional gastrointestinal diseases are nausea, vomiting, bloating, abdominal distention, diarrhea, constipation, and pain. For this reason, when functional disease is being considered as a cause of symptoms, it is important that the presence of non-functional diseases be excluded (ruled out). In fact, the exclusion of non-functional diseases usually is more important in evaluating patients who are suspected of having functional disease. This is so, in large part, because the tests for diagnosing functional disease are complex, not readily available, and often not very reliable. In contrast, the tests for diagnosing non-functional diseases are widely available and sensitive (able to diagnose most cases).



Next: What are the complications of IBS? »

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.