Spastic colon, spastic bowel, functional bowel disorder and irritable colon syndrome are all names for what doctors now refer to as irritable bowel syndrome, or IBS. According to Dr. Chung Owyang, director of gastroenterology at the University of Michigan Health System and author of the chapter on IBS in the 2009 edition of the medical reference book "Harrison's Principles of Internal Medicine," doctors define IBS as a disorder, rather than a disease, because it occurs in the absence of identifiable metabolic or anatomical phenomena.
Mechanism
IBS results from excessive contractions in the muscles lining the colon. Depending on which set of muscles---longitudinal or circular---is more affected, the result is either diarrhea or constipation.
Cause
Contractions are triggered by overactive nerves in the gastrointestinal tract, especially the colon. Other factors such as mild digestive enzyme deficiencies, overgrowth of bacteria in the small intestine and colon, hormonal imbalances and stressful life events probably contribute.
Clinical Features
People with IBS commonly complain of abdominal pain or discomfort, diarrhea, constipation, abdominal distention, flatulence, traces of blood in stool, feeling an urgent need to have a bowel movement, passing mucus and/or a sense of incomplete defecation. Only two symptoms---abdominal pain or discomfort and altered bowel habits---are required for diagnosis.
Diagnosis
Doctors use the 2006 Rome Criteria to diagnose IBS. According to the criteria, patients must experience abdominal pain or discomfort for at least six months, including at least three days per month for the preceding three months before the diagnosis is made. In addition, pain or discomfort must fulfill at least two out of the three following criteria: improvement with defecation, onset associated with alteration in the appearance of stools or onset associated with alteration in the frequency of stools.
Prevalence
According to Owyang, IBS affects 10 to 20 percent of people around the world and occurs two to three times more often in women than men. Most patients develop the disorder around the age of 20, advises the American Academy of Family Physicians, although they often avoid seeking help.
Progression
IBS rarely resolves itself, although patients sometimes experience asymptomatic intervals. Symptoms sometimes evolve. For example, patients who previously experienced constipation may later develop diarrhea.
Treatment
There is no cure for IBS. Lifestyle change represents the first line of treatment and typically involves eating more fiber, eliminating trigger foods, exercise and stress management. Medications used to treat IBS include antidepressants, antispasmodics, antidiarrheals, antibiotics, probiotics and a new class of medications known as chloride channel activators.
References
- MayoClinic.com: What Is Spastic Colon?
- MayoClinic.com: Irritable Bowel Syndrome
- American Academy of Family Physicians: Irritable Bowel Syndrome
- "Harrison's Principles of Internal Medicine (19th edition)"; Dr. A.S. Fauci et al (editors); 2008
