Re: Irritable Bowel Syndrome: A “Mesh” of a Situation

To the Editor:

We read with great interest Dr. Barnes'¹ brief report and literature review in the January/February 2012 issue of the Journal of the American Board of Family Medicine. He describes a fascinating case in which the symptoms of irritable bowel syndrome (IBS) result from a rare mechanical cause: mesh herniorrhaphy. He demonstrates the value of meticulous history taking, examination, and investigation in patients with IBS, particularly if medical management proves ineffective. Dr. Barnes' case acts as a reminder of the challenges that diagnoses of IBS (and other diagnoses of exclusion) pose, and we believe it is pertinent to briefly elaborate on this.

Well-known examples of diagnoses of exclusion (per exclusionem) include IBS, “fever of unknown origin,” chronic fatigue syndrome, and fibromyalgia. Although these conditions have well-researched questionnaires and assessment tools (eg, for bowel dysfunction),² there is a fundamental lack of understanding of both the underlying pathophysiology and the mechanism of action of their treatments. We do not imply that these conditions are without a pathologic process, nor do we suggest that they are fictitious or “psychological” (an anecdotal opinion of some physicians); rather, we believe that they represent heterogeneous clusters of unknown pathologic processes, grouped by symptoms. Forming these diagnoses occurs without objective verification, often after a crude process of elimination. In reality, we think this highlights an intrinsic desire of doctors to provide a diagnosis for patients. This diagnosis then acts as a basis on which to initiate treatment and provide, to the extent of the abilities of a modern physician, a form of reassurance to both doctor and patient. However, the use of a diagnosis of exclusion unfortunately can be tantamount to saying that a true diagnosis is not known. Herein lies the problem with modern medicine—we can image the functioning brain and examine the deepest recesses of the human body, but we remain uncomfortable uttering 3 words: “I don't know.”

To progress as a profession, we need to understand that a diagnosis of exclusion should be seen as a target for research. Individual pathologic processes must be elucidated carefully if we are to understand the myriad conditions that contribute to the aforementioned umbrella terms. Sunderji et al³ utilized electrocardiography in an attempt to elevate tako-tsubo cardiomyopathy from a diagnosis of exclusion. Ultimately, they failed, further highlighting the difficulty of these diagnoses. We must not be discouraged, but rather, continue the quest to find the best methods of discerning the constituent parts of these diagnoses. After identifying these problems we will be in a position to generate diagnoses of inclusion rather than exclusion. We will then be better able to diagnose and treat our patients, which, ultimately, is the raison d'être of a doctor.