What's the difference between IBD and IBS?
There are a lot of acronyms used in the medical field which can cause confusion for patients and practioners alike. A common question people have is, "What's the difference between IBD and IBS and is it possible to have both at the same time?"
First, a few definitions:
IBD = inflammatory bowel disease, encompasses a spectrum of disorders of the intestine including Crohn's disease, ulcerative colitis, and indeterminate colitis. The root of all of these disorders is a dysregulation of inflammation in the body, commonly targeted to the gut. The inflammation of IBD causes damage to the lining of the intestine resulting in an ulcerated appearance to the tissue on colonoscopy.
IBS = irritable bowel syndrome (popularly known as "spastic colon"), is a gastrointestinal disorder caused by hypersensitivity of the nerves which line the intestines. Our guts are always in motion, moving in waves of muscular contractions to help digest food (peristalsis). For most individuals, the normal movements of the gut are imperceptible. In IBS, there is a dysregulation of the how sensations are felt by the nerves in the gut causing people to feel uncomfortable even with normal peristalsis. In contrast to IBD, the lining of the intestine on colonoscopy looks normal. It is the abnormal nerves impulses that cause symptoms.
How are IBD and IBS similar?
The main similarity between IBD and IBS is that patients with either of these conditions can have very similar symptoms. Symptoms that are associated with both IBD and IBS include: abdominal pain, diarrhea, constipation, urgency, bowel frequency, bloating, nausea, and changes in appetite. Another similarity is that in a subset of patients, IBD or IBS can be triggered by a gastrointestinal infection.
How are IBD and IBS different?
IBD and IBS differ in terms of the underlying cause of the disease process, some symptomatology, laboratory tests, and treatment. As mentioned above, IBD is caused by inflammation in the intestine, whereas symptoms of IBS are cause by hypersensitivity of the nerves in the gut. Furthermore, there are some symptoms which are found in IBD that are not typically seen in IBS, including: bloody stool, weight loss, fever, oral ulcers, skin rashes, joint pains. In order to distinguish between the two, physicians rely on patient histories as well as lab tests and endoscopic results. In IBD, lab tests can indicate inflammation in the blood and stool; in IBS, these lab tests are usually normal. As noated above, inflammation of the lining of the intestine is typically seen on colonoscopy in IBD, whereas, the lining of the intestine looks normal in IBS. Finally, the treatments for the two conditions are vastly different.
Is it possible to have both IBD and IBS at the same time?
While the majority of IBD and IBS patients carry one diagnosis exclusively, it does appear that a small subset of individuals can have both. Often times this occurs in the setting of IBD when a patient has flare symptoms but turns out to have normal lab values and endoscopic tests. For these individuals, some of the medicines that treat spasms in IBS may be helpful.