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Irritable Bowel Syndrome vs. Inflammatory Bowel Disease

Author:

I am a board-certified anesthesiologist in Lake Tahoe, California. I write from the perspective of both a doctor and a patient.

It is easy to confuse IBS (irritable bowels syndrome) with IBD (inflammatory bowel disease) since the names are so similar and the initials even more so. And, make no mistake, both are distressing illnesses to those who suffer from them.

The differences, however, are significant. While they both affect the gastrointestinal (GI) tract, there are distinct factors that differentiate these conditions.

Diagram of the Digestive System

Irritable bowel syndrome causes spasms of the intestines. Ulcerative colitis affects the large intestine which includes the colon and rectum. Crohn's disease affects the small and large intestine, as well as other parts of the digestive system.

Irritable bowel syndrome causes spasms of the intestines. Ulcerative colitis affects the large intestine which includes the colon and rectum. Crohn's disease affects the small and large intestine, as well as other parts of the digestive system.

Irritable Bowel Syndrome vs. Inflammatory Bowel Diseases

 Irritable Bowel SyndromeInflammatory Bowel Disease- Ulcerative ColitisInflammatory Bowel Disease- Crohn's Disease

Symptoms

gas, abdominal pain, urgency, diarrhea and/or constipation, food sensitivities

Bloody diarrhea, mucous in stool, abdominal pain, urgency, fatigue, fever,

Bloody diarrhea, mucous in stool, abdominal pain, fatigue, fever, urgency

Affected Part of GI System

colon, maybe small intestine

colon/rectum only

large and small intestine, as well as other parts of the digestive system sometimes

Tests for Diagnosis

rule out other conditions, no specific test

colonoscopy with biopsy, specialized blood tests

colonoscopy with biopsy, specialized blood tests

Causes

Unknown- may be a combo of inherent and environmental factors

autoimmune/genetic and likely environmental trigger

autoimmune/genetic and likely environmental triggers

Treatments

Behavioral and dietary modifications, some medications to relax the spastic intestine

Dietary changes of benefit in some people to alleviate symptoms, medication, surgery to remove colon

Dietary change of benefit to some people, medications, surgery only in emergencies or as last resort

Irritable Bowel Syndrome (IBS)

IBS affects more people than does inflammatory bowel disease. Some estimates claim that 20 percent of Americans are bothered by irritable bowel syndrome. Because many people who have symptoms of the disease don't seek medical care, the exact number is hard to pinpoint.

Irritable bowel syndrome is characterized by abdominal gas, pain or cramping, diarrhea (without blood) and/or constipation. On examination with colonoscopy, there are no structural changes in the bowel. Since there are not distinctive findings, other diagnoses must be ruled out. Your doctor will make sure you don't have food allergies or enzyme problems (like lactose intolerance), inflammatory bowel disease, infectious processes, celiac disease, and so on.

IBS is sometimes called spastic colon due to the finding that the colon is more active with stronger and more frequent contractions in people with active IBS.

Treatments for Irritable Bowel Syndrome

Treatments for IBS are aimed at eliminating triggers and slowing the contractions of the intestines.

Because psychological factors such as stress and fatigue can be triggers for attacks, behavioral therapy or modification can be helpful. Relaxation techniques, exercise and learning new methods of stress management are great ways to start getting this condition under control.

Medications can be effective for a large number of patients. Medical therapy is aimed at relieving the most prevalent symptoms. Anti-diarrheals, anti-spasmodics, anti-anxiety medicines, pain medicines, laxatives, anti-depressants and others have been used in various patients.

Ulcerative Colitis

During colonoscopy, ulcers can be seen lining the large intestine in ulcerative colitis. The yellow discoloration represents inflammation and ulceration. The lining should be smooth, uniform and pink.

During colonoscopy, ulcers can be seen lining the large intestine in ulcerative colitis. The yellow discoloration represents inflammation and ulceration. The lining should be smooth, uniform and pink.

Inflammatory Bowel Disease (IBD)

Inflammatory bowel disease is actually a term used to refer to ulcerative colitis (UC) and Crohn's disease (CD), collectively. Both of these entities cause ulcers in the lining of the digestive tract leading to abdominal pain and bloody diarrhea with mucous. In severe cases, bleeding can cause anemia, and other complications can occasionally lead to death. Chronic cases can be life-threatening—either because of the disease or the medications used to treat it.

Both UC and CD are considered to be autoimmune diseases. That means that for some reason, the body's immune system mistakes the lining of the digestive tract as a foreign substance and tries to attack and eliminate it.

No one knows why some people get autoimmune diseases like those of IBD. Most likely, it is a complicated interaction involving genetic and environmental factors. For example, it is possible that someone has a gene that makes them vulnerable to the disease, and then an outside factor like a virus or toxin activates the immune system.

The immune system forms antibodies against the digestive system. Unfortunately, the immune system has memory and once the antibodies are formed, they can be activated continuously or repeatedly.

Treatments for Inflammatory Bowel Disease

Both ulcerative colitis and Crohn's diseases have variable presentations. In other words, either can be infrequent and very mild, or chronic, debilitating, and life-threatening.

The first medicines used are often those with the least side effects. It makes sense to try less toxic medications first.

  • Anti-inflammatory drugs: Sulfasalazine and mesalamine are used to try to decrease the inflammation in the bowel.
  • Pain relievers: Corticosteroids are used to suppress inflammation as well. They also inhibit normal function of the immune system. It is best to use steroids for short-term control of symptoms only since they have significant side effects when used in the long-term. Unfortunately, many people with severe disease end up on steroids (such as prednisone) as a maintenance medicine.
  • Immunosuppressants: Immunosuppressants and immunomodulators are reserved for patients who don't respond to other medicines. Some of these medicines are the same ones given to organ transplant patients to suppress the immune system, so are quite potent. Others, such as Remicade and Humira, are newer medicines that also interfere with immune function and require very close monitoring by a doctor while they are being used.
  • Surgery: Surgery can be used for severe ulcerative colitis. Removing the colon and rectum can 'cure' the disease (although manifestations such as joint pain and other associated symptoms may still occur). Either an ileostomy is placed (and usually is, at least temporarily), or the small intestine is connected to the anus after the colon and rectum are surgically excised. Bowel movements will be frequent, soft and often urgent, but should be very improved compared to before surgery.

Because the large and small intestines are affected in Crohn's, there is no curative surgery. If part of the intestine is removed, the Crohn's can still reappear in the remaining sections.

This content is for informational purposes only and does not substitute for formal and individualized diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed medical professional. Do not stop or alter your current course of treatment. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

Comments

Maria Eyles on March 31, 2015:

Thank you, Tahoe Doc! My beautiful dog Raphael has suffered from IBD since he was a puppy. (Please see my article on Hubpages "Living with Canine IBD.") I have chronic IBS. You do a GREAT job of explaining the difference. I will refer all my friends here (the lucky ones, heh, heh...)

Both disorders are heart-breaking but my dog has it so much worse than I do. Both his colonoscopy and endoscopy revealed terrible ulceration, but thank God he has been in remission (on prednisone) the past three years. Thank you again. Great writing! Maria V Eyles

Jason Poquette from Whitinsville, MA on November 30, 2012:

Great article. I'm tweeting it to my friends...right around lunch time. LOL. Loved it.

Nettlemere from Burnley, Lancashire, UK on November 29, 2012:

This is very useful information and clears up a bit of confusion for me in that I'd heard of Crohns disease in humans and inflammatory bowel disease in animals, but didn't know there was a cross over with the names.