Irritable bowel syndrome, or IBS, is a functional disorder of the colon characterized by recurrent episodes of abdominal pain and abnormal bowel habits. Historically, patients with IBS were subjected to extensive diagnostic testing in order to exclude a metabolic or anatomic explanation for their symptoms. However, most of these work-ups produced nothing more than frustration and big bills. According to Dr. Chung Owyang, chief of Gastroenterology for the University of Michigan Health System, such work-ups are now reserved only for those patients who exhibit alarming symptoms of IBS.
Age
According to the American Academy of Family Physicians, patients usually develop IBS around the age of 20, although, in many cases, several years elapse before patients seek treatment. IBS rarely onsets in patients over 50; however, the risk of several other diseases, such as cancer, starts to increase at this age. Therefore, the American College of Gastroenterology defines age as a potential trigger for IBS, and recommends colonoscopies for African American patients over 45 and all other patients over 50.
Bleeding
Rectal bleeding or symptoms that suggest it, such as anemia, unintentional weight loss and black, tarry or sticky stools, also require further evaluation. Under normal circumstances, IBS does not produce damage or even inflammation in the colon. Therefore, bleeding would be an unexpected symptom. While patients could experience bleeding indirectly caused by IBS---such as that due to hemorrhoids or anal fissures triggered by severe constipation--the authors of a 2008 review published in the "Nature Clinical Practice: Gastroenterology and Hepatology" journal series say that rectal bleeding is considered alarming because of its high positive predictive value for colorectal cancers.
Family History
According to the American Gastroenterology Association, family history of colorectal cancer, inflammatory bowel disease and celiac sprue constitutes another cue for further diagnostic testing. A doctor will often ask about a family member's age at diagnosis. In the case of colorectal cancers, cancers that appear later in life are considered less diagnostically relevant than those that occur in younger patients. Colorectal cancers that appear in younger people, multiple family members or in conjunction with certain other cancers such as breast or endometrial cancers, may be taken more seriously because they strongly suggest a hereditary component.
Nocturnal Symptoms
According to "Harrison's Principles of Internal Medicine," unlike patients with bowel diseases, patients with bowel disorders such as IBS very rarely complain of sleep interruption due to pain or other symptoms. In fact, diarrhea due to IBS occurs almost exclusively during waking hours. The "Nature Clinical Practice: Gastroenterology and Hepatology" journal article describes conflicting evidence on the utility of nocturnal symptoms as a predictor for more serious disease. According to the article, most studies report no utility for the inclusion of nocturnal symptoms as an alarm feature. However, a few studies suggesting otherwise lead many doctors to prefer more evaluation rather than less for IBS patients who complain of nighttime symptoms.
References
- "Harrison's Principles of Internal Medicine"; A.S. Fauci, et al.; 2008
- "American Journal of Gastroenterology"; An Evidence-Based Systematic Review on the Management of Irritable Bowel Syndrome; American College of Gastroenterology Task Force on IBS; January 2009
- "Nature Clinical Practice: Gastroenterology and Hepatology"; Efficient Diagnosis of Suspected Functional Bowel Disorders; J. Gunnarsson and M. Simren; September 2008
- "Gastroenterology"; AGA Technical Review on Irritable Bowel Syndrome; D.A. Drossman et al.; Dec. 2002
- American Academy of Family Physicians: Irritable Bowel Syndrome
