To the Editor:
Two articles published recently in Mayo Clinic Proceedings
1
, 2
are relevant to an important clinical issue: the misdiagnosis of acute colonic diverticulitis in patients with irritable bowel syndrome (IBS). As clearly described in these articles, abdominal pain and disordered bowel habits are common to both disorders, and symptom severity varies in both. Furthermore, patients with either of these disorders typically have tenderness on examination, most often in the lower abdomen. Computed tomography (CT) of the abdomen and pelvis, the most commonly used diagnostic test for diverticulitis,2
is often not urgently available for clinic patients, and some patients with CT-documented diverticulitis have no fever or leukocytosis.3
Therefore, similar clinical features and the inability to conclusively exclude diverticulitis underlie the potential for physicians to incorrectly attribute abdominal pain in outpatients to diverticulitis when it is actually caused by IBS.Most patients in whom diverticulitis is diagnosed and treated with antibiotics in the Kaiser Permanente Medical Care Program of Southern California are clinic patients,
4
as in other settings.5
A recent retrospective study of patients treated with antibiotics for diverticulitis at Kaiser Permanente compared outpatients managed without CT with emergency department/inpatients managed with CT. More outpatients had prior diagnoses of diverticulitis, including outpatient-managed episodes, and they had increases in 8 symptom-based somatic and 3 mental comorbidities as well as greater dispensing of antispasmodics, anxiolytics, and serotonin receptor agents. The somatic comorbidity that varied most between the groups was IBS, which had been diagnosed in 15.1% (2399/15,846) of outpatients vs 9.6% (361/3750) of emergency department/inpatients. Outpatients with a prior diagnosis of diverticulitis had 1.5-fold greater odds of having IBS than outpatients without this history. Although the investigators could not determine which patients had mild diverticulitis vs an exacerbation of IBS, these and other findings constitute multiple types of indirect and concordant evidence of the misattribution of IBS pain to diverticulitis.4
Extrapolation of the Kaiser Permanente data to the US population reveals that a misdiagnosis rate of only 10% in clinically diagnosed outpatients would approximate 40,000 patients a year.
4
Misdiagnosis causes much unnecessary antibiotic use and inherent cost and risk. Thus, in addition to the structural disorders discussed in the differential diagnosis of diverticulitis,2
practitioners should carefully consider IBS in outpatients with lower abdominal pain, bowel habit abnormality, and abdominal tenderness. Chronicity of symptoms may be a particularly helpful feature. Also, Bharucha et al1
described details of the physical examination that can help distinguish functional from structural disorders, but there may be uncertainty in some cases. In view of the overlap of clinical features of IBS and mild diverticulitis and recent authoritative advice that antibiotics be used selectively in patients with uncomplicated diverticulitis,2
management without systemic antibiotic should be considered when the diagnosis is uncertain.References
- Common functional gastroenterological disorders associated with abdominal pain.Mayo Clin Proc. 2016; 91: 1118-1132
- Diverticulosis and diverticulitis.Mayo Clin Proc. 2016; 91: 1094-1104
- Acute diverticulitis: demographic, clinical and laboratory features associated with computed tomography findings in 741 patients.Aliment Pharmacol Ther. 2012; 36: 886-894
- Clinically diagnosed acute diverticulitis in outpatients: misdiagnosis in patients with irritable bowel syndrome.Dig Dis Sci. 2016; 61: 578-588
- Practice parameters for the treatment of sigmoid diverticulitis.Dis Colon Rectum. 2014; 57: 284-294
Article Info
Footnotes
Editor's Note: When publishing a letter that comments on an article published previously in Mayo Clinic Proceedings, it is the journal's policy to invite the author(s) of the referenced article to publish a response. Drs Adil Bharucha and Joseph Feuerstein were invited to respond, and although they were supportive of this letter, they felt the content of the letter did not require a reply.
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© 2016 Mayo Foundation for Medical Education and Research
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- Common Functional Gastroenterological Disorders Associated With Abdominal PainMayo Clinic ProceedingsVol. 91Issue 8
- PreviewAlthough abdominal pain is a symptom of several structural gastrointestinal disorders (eg, peptic ulcer disease), this comprehensive review will focus on the 4 most common nonstructural, or functional, disorders associated with abdominal pain: functional dyspepsia, constipation-predominant and diarrhea-predominant irritable bowel syndrome, and functional abdominal pain syndrome. Together, these conditions affect approximately 1 in 4 people in the United States. They are associated with comorbid conditions (eg, fibromyalgia and depression), impaired quality of life, and increased health care utilization.
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- Diverticulosis and DiverticulitisMayo Clinic ProceedingsVol. 91Issue 8
- PreviewDiverticular disease is a common condition that is associated with variable presentations. For this review article, we performed a review of articles in PubMed through February 1, 2016, by using the following MeSH terms: colon diverticula, colonic diverticulitis, colonic diverticulosis, colonic diverticulum, colonic diverticula, and diverticula. Diverticula are structural alterations within the colonic wall that classically form “pockets” referred to as diverticula. Diverticula form from herniation of the colonic mucosa and submucosa through defects in the circular muscle layers within the colonic wall.
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