The acronyms are similar, as are some of the symptoms, but contrary to common belief Inflammatory Bowel Disease (IBD) and Irritable Bowel Syndrome (IBS) are not the same thing. 

Irritable Bowel Syndrome affects approximately 55 million Americans (that’s about 1 in 5 people) and is second only to the common cold for missed days from school and work. IBS is said to be a functional disorder of the intestines – functional meaning that the normal muscular contractions of the digestive tract become irregular and uncoordinated making it difficult for the intestines to process and eliminate waste correctly. 

The improper functioning of the digestive tract can result in symptoms such as gas, bloating, abdominal distention, abdominal cramps, diarrhea and/or constipation, abdominal cramps. Other, less common symptoms of IBS include mucus in the stool, a feeling of incomplete evacuation after a bowel movement, and nausea. Blood tests, stool tests, colonoscopy, and small bowel series x-rays all come back normal. IBS is not a disease, but a functional disorder of the digestive tract that is diagnosed after all other possible disorders have been ruled out. Other disorders that can often be confused for IBS include, celiac disease, benign tumors, colon cancer, Crohn’s disease, ulcerative colitis, diverticulitis, endometriosis, food poisoning, or food intolerances such as lactose intolerance. 

In IBS there are no physical signs of damage or disease in the tissues of the bowel.  

However, in patients who have Inflammatory Bowel Disease (IBD) the tissues of the intestines are inflamed and/or ulcerated. Patients who have IBD are diagnosed either with Ulcerative Colitis or Crohn’s disease. And IBD is thought to be an auto-immune disorder. 

Symptoms indicative of IBD include diarrhea, blood in the stool, and weight loss. Blood tests often show IBD patients are low in iron, and an ESR, or Erythrocyte sedimentation rate which is a marker for inflammation, tends to be elevated. Stool studies in the patient with IBD will often show occult blood (not visible to the naked eye) as well as white blood cells. And a colonoscopy or small bowel series show abnormalities.  

Below are portions of the clinical descriptions of Ulcerative Colitis (UC) and Crohn’s Disease from the web site of the Crohn’s and Colitis Foundation of America. 

“Ulcerative colitis is a chronic (ongoing) disease of the colon, or large intestine. The disease is marked by inflammation and ulceration of the colon mucosa, or innermost lining. Tiny open sores, or ulcers, form on the surface of the lining, where they bleed and produce pus and mucus. Because the inflammation makes the colon empty frequently, symptoms typically include diarrhea (sometimes bloody) and often crampy abdominal pain.

The inflammation usually begins in the rectum and lower colon, but it may also involve the entire colon. When ulcerative colitis affects only the lowest part of the colon -- the rectum -- it is called ulcerative proctitis. If the disease affects only the left side of the colon, it is called limited or distal colitis. If it involves the entire colon, it is termed pancolitis.”