World Journal of Colorectal Surgery

: 2020  |  Volume : 9  |  Issue : 1  |  Page : 1--6

The need for routine colonoscopy after acute diverticulitis revisited

Michelle L Cooper1, Cu Tai Lu1, Harald Puhalla1, Hajir Nabi2, Michael Von Papen1,  
1 Department of General Surgery, Gold Coast University Hospital, Griffith University, Queensland, Australia
2 University of Queensland, Queensland, Australia

Correspondence Address:
Dr. Michelle L Cooper
Department of surgery, Gold Coast University Hospital, Hospital Boulevard, Southport, Queensland - 4215


Background: The utility of routine outpatient colonoscopy after the conservative management of complicated and uncomplicated colonic diverticulitis has become questionable. Recent literature suggests this time-honored practice after uncomplicated diverticulitis is to be of little benefit, although uncertainty still persists regarding complicated diverticulitis. Objective: We analysed the rates of benign and malignant pathology identified on colonoscopy after conservatively managed uncomplicated and complicated diverticulitis in a hospital where such colonoscopies have been routine practice. Design: A retrospective cohort study was conducted. Setting: Gold Coast Hospital, Southport, Queensland, Australia. Patients and Methods: All patients who were admitted to the Gold Coast Hospital, Southport, Queensland, Australia, between June 2007 and June 2010 diagnosed with acute uncomplicated and complicated diverticulitis were included in the study. The patients were followed up and colonoscopy reports and histology results obtained. Main Outcome Measures: Benign and malignant pathology post uncomplicated and complicated diverticulitis. Sample Size: 144 patients were eligible for inclusion. Results: Between June 2007 and June 2010, 1073 patients were hospitalized with an admission diagnosis coding for diverticulitis. Of these, 144 patients had a computed tomography (CT) which confirmed the diagnosis of acute diverticulitis. Complete colonoscopy and histology data were obtained for 107 of these patients. Of these, 32 patients (29.91%) had pathology found at colonoscopy. One patient (0.9%) was found to have adenocarcinoma of the colon. Conclusion: Colonoscopy follow-up for acute diverticulitis has remained acceptable in many units to exclude alternate colonic pathology. However, recent literature has questioned the utility of this practice. This study – in keeping with this growing body of international literature – found the rate of synchronous/alternative pathology to be comparable to that of asymptomatic patient populations. Routine colonoscopies after uncomplicated colonic diverticulitis confidently diagnosed with a CT scan, therefore, cannot be justified. Limitations: Retrospective nature and sample size. Conflict of Interest: None.

How to cite this article:
Cooper ML, Lu CT, Puhalla H, Nabi H, Papen MV. The need for routine colonoscopy after acute diverticulitis revisited.World J Colorectal Surg 2020;9:1-6

How to cite this URL:
Cooper ML, Lu CT, Puhalla H, Nabi H, Papen MV. The need for routine colonoscopy after acute diverticulitis revisited. World J Colorectal Surg [serial online] 2020 [cited 2020 Jul 12 ];9:1-6
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Full Text


In recent decades, the reported prevalence of diverticular disease in western countries has increased.[1] Between 2% and 25% of patients with diverticulosis will experience diverticulitis and its complications over their lifetime.[2] Computed tomography (CT) is the safest and most cost-effective method for diagnosing diverticulitis demonstrating false-negative rates of 2%–21%.[3],[4] In western populations, the sigmoid colon remains the predominant site for diverticular disease. This is also true for the most common location of colonic polyps and carcinomas.[5] Some authors have suggested the diverticular disease is a risk factor for colon cancer, with colon cancers even having been described within diverticulum.[6]

Colonoscopy is recognized as the gold standard for definitive colorectal cancer diagnosis.[7],[8] Historically, colonoscopy has been used to examine the colon following an episode of acute colonic diverticulitis to evaluate the extent of diverticular disease and to exclude other benign and malignant pathology.[9] With the advent of more accurate CT imaging, some argue that a routine outpatient colonoscopy is no longer necessary following acute uncomplicated diverticulitis.[10],[11]

Significant variability exists in clinical practice regarding the use of routine outpatient colonoscopy in the follow-up of acute uncomplicated diverticulitis despite a growing body of evidence against its benefit. In contrast, the evidence of benefit for follow-up colonoscopies after complicated diverticulitis is comparatively sparse, and thus most clinicians still offer routine outpatient colonoscopy in this setting.

This study highlights that the discrepancy between recent literature and clinical practice is justified and investigates the rates of benign and malignant pathology associated with the use of routine outpatient colonoscopies to follow-up episodes of both uncomplicated and complicated diverticulitis.

 Patients and Methods

A retrospective single-center cohort study was conducted using medical records from all patients who were admitted to the Gold Coast Hospital (GCH), Southport, Queensland, Australia, from June 2007 to June 2010 with a CT diagnosis of acute diverticulitis. The diagnosis was made clinically and confirmed by an abdominal CT scan with intravenous and oral contrast. The CT reports, images, and clinical notes were reviewed, and patients with both uncomplicated and complicated acute diverticulitis were included in the study. Acute diverticulitis was defined in accordance with previous studies of CT imaging.[2],[11],[12],[13] All patients who matched these clinical and radiological criteria were included in the study. Eleven patients who went on to have immediate inpatient operative management were excluded from the study.

Routine outpatient colonoscopies were the favored method of follow-up used by all of the surgeons included in this study during the review period. The findings from all colonoscopy reports were reviewed. All biopsies or polypectomies were assessed by histopathology and categorized as follows: hyperplastic, tubular adenoma, tubulovillous adenoma, and adenocarcinoma. The presence of low-grade dysplasia and high-grade dysplasia associated with these adenomas was also classified [Table 1].{Table 1}

Uncomplicated colonic diverticulitis was defined as the presence of localized colonic wall thickening and/or fat stranding of pericolonic fat, with the exclusion of local and distant infective collections. A modified Hinchey classification [Table 2] was used for grading complicated cases of diverticulitis.{Table 2}

The primary outcome being investigated was the incidence of benign and malignant colonic pathology identified at colonoscopy postacute diverticulitis admission.


A total of 1073 CT scans of patients where diverticulitis was one of the differential diagnoses at presentation were reviewed from Synapse and Impax imaging databases from the 3-year study from June 29, 2007, to June 30, 2010, at the GCH. A total of 144 patients were identified with a CT confirmed diagnosis of acute diverticulitis and included in the study [Figure 1]. The 144 patients consisted of 69 (47.9%) males and 75 (52.1%) females. Ninety-one (63.2%) cases were classified as uncomplicated diverticulitis, while 53 (36.8%) patients were classified as complicated [Table 2]. The mean age in the uncomplicated group was 56.86 years (age 28–91) and 53.11 years (age 30–89) in the complicated group [Table 3].{Figure 1}{Table 3}

Chi-square tests were used to assess the difference between uncomplicated and complicated diverticulitis groups. P < 0.05 was considered statistically significant.

The sigmoid colon was found to be the most common location for diverticulitis [Table 4]. Of the 144 patients, 107 had available colonoscopy reports with histology, 36 (25.0%) patients had no colonoscopy (reasons explained in [Figure 1], and one patient underwent a private colonoscopy and results were unavailable. Hence, 107/144 (74.3%) patients fulfilled the criteria to be included in the colonoscopy group. Colonoscopy completion rates (to caecum or terminal ileum) were 100% [Table 3]. The colonoscopies were performed by a variety of gastroenterologists and surgeons.{Table 4}

Seventy-five patients (70.1%) had no polyps identified at colonoscopy. Colonic polyps were present in 32 (29.91%) patients and polypectomy performed in 31 (28.04%). One patient was on warfarin at the time of colonoscopy, and the polyp was not removed as it macroscopically appeared hyperplastic on visual inspection. This patient was referred for follow-up colonoscopy in 5 years. The polyps identified are represented in [Table 1].

One patient (0.9%) – a 49-year-old female – had an adenocarcinoma and went on to have a surgical resection. Histopathology was a moderately differentiated adenocarcinoma - T3 N1 M0. This patient's colonic adenocarcinoma was in the same location as her diverticulitis in the descending colon.

It is important to note that while the primary outcome being investigated was the incidence of benign and malignant colonic pathology identified at colonoscopy postacute diverticulitis admission, no other significant colonic pathologies were identified, such as inflammatory bowel disease, ischemic colitis, or infectious colitis.

[Table 5] displays our results alongside other large comparable patient studies.{Table 5}


Eleven (7.6%) patients required operative intervention during their acute admission [Table 6]. These patients were excluded from the study. Three (2.1%) patients had CT guided percutaneous drainage of intra-abdominal collections. Five (3.47%) patients experienced complications during their acute admission. One (0.7%) patient had a cerebrovascular accident. One (0.7%) patient experienced a lower respiratory tract infection [Table 6].{Table 6}

Three (2.1%) patients had allergic reactions to antibiotics, and hence, their antibiotic regime was changed. One of these patients with uncomplicated diverticulitis had an anaphylactic reaction to the antibiotics administered. The most common in-patient antibiotic regime for acute diverticulitis was ampicillin, metronidazole, and gentamicin. Patients were most commonly discharged home on amoxicillin with clavulanic acid. There were no recorded complications from colonoscopy in this cohort of patients.


We have the seventh largest patient cohort published to date – of which we are aware-investigating this important clinical question. The diagnosis of diverticulitis in the era before CT was largely clinically based, and many would argue likely inaccurate.[12] Many clinicians still advocate for utilizing routine colonoscopy to confirm the presence of diverticular disease and exclude other benign and malignant colonic pathology after acute diverticulitis.[14] Colonoscopy is generally performed after a minimum of 6–8 weeks after an episode,[15],[16] to avoid complications associated with insufflation of the colon.[10],[17]

A recent meta-analysis with 68,324 participants showed that the detection rate of advanced colonic neoplasia from colonoscopic screening of average and high-risk asymptomatic individuals was 5.8% with invasive cancers accounting for 0.8%. They also reported a nonmalignant polyp rate of 19.5%.[18] Another study of 269,144 asymptomatic screening colonoscopies found advanced colonic neoplasia in 7.9% and colorectal cancer in 0.8%.[19] A systematic review in 2013 showed a pooled proportion of nonmalignant polyps in 16.5% of 1125 patients and malignancy in 1.6% of 1970 asymptomatic population screening patients.[20]

Nearly half of the all colonic carcinomas and a similar proportion of colonic polyps are situated in the sigmoid colon. This is also the principal site of colonic diverticula in 65% of patients.[21]

Although early twentieth century investigators suggested a causal relationship between diverticulitis and cancer of the colon, most contemporary clinicians agree such a connection does not exist.[22] We discovered the rate of colonic neoplasia was similar/less than that of general screened populations – as per similar recent studies.[23]

Colonoscopy has been shown to be accurate in 83% of patients referred for a radiological suspicion of malignancy in a diverticula bearing sigmoid colon.[24] Colonoscopy may be required to correctly differentiate acute diverticulitis from a segmental colonic abnormality caused by Crohn's disease, bacterial infection, ischemia, cancer, or clostridium difficile colitis occurring in association with diverticulosis.[20],[25],[26] Other than polyps and malignancy, we did not see alternative pathology within our cohort.

Previous studies in patients with diverticulosis have found conflicting results. Some papers have found an increase, a decrease, and others still have found no difference in the incidence of colorectal polyps/carcinoma.[14],[26]

Where uncertainty regarding synchronous or alternate pathology to diverticulitis exists on CT imaging, the diagnostic importance of a follow-up colonoscopy remains unchallenged and dogmatic.[10],[11],[27]

Our findings are similar to a recent meta-analysis suggesting patients with a confident CT diagnosis of acute uncomplicated diverticulitis have a similar or reduced risk of advanced colorectal neoplasia compared with the general population. These results suggest that patients with acute diverticulitis need not be prioritized above those eligible for general population-based screening.[13],[20],[23],[28]

With increasing pressures on healthcare resource distribution, it is important not to weigh down endoscopy services with nonevidence-based practices such as those of routine colonoscopies after acute uncomplicated diverticulitis diagnosed with accurate CT imaging. With the increased prevalence of diverticulitis, the utilization of outpatient colonoscopies should be limited to those with additional risk factors or uncertain imaging findings.[29],[30]

The authors recognize that the weaknesses of this study are its retrospective nature and sample size. However, our findings are in keeping with those of recent studies and further add to the current body of evidence against routine colonoscopy in uncomplicated diverticulitis. Questions regarding the role of routine outpatient colonoscopies to follow-up conservatively managed complicated colonic diverticulitis remains to be definitively answered. A follow-up study with a larger cohort of patients would be recommended before making definitive conclusions about whether to change practice with respect to referring patients for routine colonoscopy after complicated acute diverticulitis managed conservatively.


Shu Kay Ng, Associate Professor in Biostatistics, Griffith University.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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