Acute Uncomplicated Diverticulitis: Updated Evidence for Same Old Questions : Diseases of the Colon & Rectum

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Commentaries and Educational Content: Resident’s Corner

Acute Uncomplicated Diverticulitis: Updated Evidence for Same Old Questions

Correa Bonito, Alba M.D.; Blanco Terés, Lara M.D.

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Diseases of the Colon & Rectum 66(4):p 493-496, April 2023. | DOI: 10.1097/DCR.0000000000002750
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  • Which patients are good candidates for outpatient management?
  • When is a nonantibiotics strategy advisable?
  • How can future episodes be avoided?
  • Is there a role for elective surgical treatment in cases of AUD?


Approximately 50% of the population aged >60 years have colic diverticula1 in occidental countries. Most cases are asymptomatic, and only a small minority will present with an episode of acute diverticulitis at some point in their lives. Seventy-five percent of the cases of diverticulitis are AUD, defined as those cases diagnosed without pneumoperitoneum, abscess, or peritonitis.2 AUD management has evolved as the understanding of the pathophysiology has changed from a clearly infectious process to a mixed infectious and inflammatory process. General rules applicable to all patents have been replaced by guidance that is meant to be applied on a case-by-case basis. Antiquated treatments of universal hospital admission, bowel rest, and antibiotics have been replaced by selective outpatient management and the omission of antibiotics in selected patients.3–6 Potential benefits of this new treatment strategy include lower utilization, lower costs, and avoiding antibiotic resistance and adverse effects. Appropriate selection of patients for different treatment options is mandatory and the cornerstone for successful management. Emerging data have allowed for postrecovery strategies to be used to prevent recurrence.

An abdominal CT confirmed the clinical suspicion of acute uncomplicated diverticulitis.


Patients typically present with several days of lower left quadrant abdominal pain, sometimes associated with fever, diarrhea, constipation, or tenesmus. The differential diagnosis includes neoplasia and colitis, including Crohn’s disease and ischemic and stercoral colitis. Evidence of complicated disease includes symptoms of obstruction or air or stool passage through the bladder or vagina that would suggest a fistula. Lower left quadrant tenderness is typically appreciated on examination. Sometimes, a palpable mass may be appreciated at this location. Blood tests usually show leukocytosis or an increase of C-reactive protein (CRP), although there are no pathognomonic values that accurately predict the presence of diverticulitis. The diagnosis is confirmed by a contrast-enhanced abdominopelvic CT scan. There are several classifications, and most of them are based on CT findings. Radiologic criteria for the diagnosis of an AUD are inflammation of the colic wall or pericolic fat without free air or abscesses. Unfortunately, there is no unanimity in the definition of AUD. Ultrasonography has also been described as a useful diagnostic alternative, although it has important limitations in detecting complicated diseases. Colonoscopy in the acute setting is contraindicated because of the high risk of complications.


Current management of this common disease has evolved to increasingly conservative measures and minimally invasive surgical interventions, with patient selection driving decision-making. Outpatient treatment is typical for those with good overall health without severe comorbidities and who can reliably follow instructions and return to the hospital if needed. It is important to highlight that age per se is not a limit, but elderly patients are treated by in-hospital admission more commonly as they may not manifest some of the common findings as readily as younger patients. Other factors that suggest that inpatient management would be preferred include fever, tachycardia, and the inability to tolerate oral intake or the need for intravenous analgesics. Patients with significant immunosuppression are also frequently hospitalized. Most patients continue to be managed with antibiotics; however, selected patients with an overall low-risk presentation and a lack of leukocytosis or fever (and, by some recommendations, a normal CRP level) can be managed without antibiotics. Omission of antibiotics is not appropriate for patients with complicated disease, such as abscess or free air observed on CT. A recent meta-analysis proved that, in these selected cases, outpatient management without oral antibiotic therapy is safe and successful, with an overall failure rate of 4.3% with only 0.19% of patients who needed surgery or percutaneous drainage.7 These studies had some differences in definitions but generally included patients without high-risk factors such as older age, immunosuppression, severe comorbidities, fever, tachycardia, leukocytosis, and elevated CRP. Recent randomized controlled trials like AVOD,3 DIABOLO,4 DINAMO,6 and the one by Jaung et al5 demonstrated that treatment of AUD without antibiotics is safe in selected patients. Rates of urgent surgery or percutaneous drainage and readmission rates were similar in both groups. Rates of recurrence after this treatment without antibiotic therapy have also been studied in the DIABOLO4 and AVOD3 trials, without differences from those patients treated with antibiotics.

Several strategies have emerged to prevent recurrences after the first AUD episodes, such as the use of rifaximin, mesalamine, or fiber supplementation. The largest meta-analysis published on the role of mesalamine did not demonstrate a role in reducing the recurrence of the episodes, but it did show improvement in symptom relief and prevention of secondary diverticulitis in symptomatic patients with diverticula.8 A Cochrane systematic review of 7 trials showed no benefit of mesalamine9 for the prevention of recurrent diverticulitis. More convincing data are available for the use of rifaximin plus fiber supplementation, which has been proven as a good tool for symptom control and prevention of complications after the first episode.10 Rifaximin is given at a dose of 400 mg twice per day for 7 days each month. The use of rifaximin and other manipulations of the microbiome in the secondary prevention of diverticulitis is the focus of considerable research, and the role of this treatment strategy will be better defined. Although strong evidence is lacking, increased fiber intake as a protective measure to prevent later episodes is largely recommended. A randomized controlled trial and systematic review demonstrated that a high-fiber diet significantly reduced pain and improved overall clinical symptoms by avoiding constipation.11

The decision of who should have elective sigmoid resection after an episode of AUD is also controversial. The practice of universal resection based on the number of episodes or age of the patient has been abandoned. Elective surgery must be individualized, as the rate of recurrence is incompletely understood, and recurrence requiring emergency surgery is lower than previously considered. Furthermore, up to 80% to 90% of patients who require emergency surgery are at the index episode.12 Considerations favoring elective surgery after resolution of AUD include several episodes, especially when requiring hospitalization; persistent residual symptoms; inconsistent access to health care; and patient preference. It is important to bear in mind the risk of surgical complications including anastomotic leak or stoma creation when considering the benefits of elective surgery.


Treatment of AUD is evolving toward more outpatient management and the omission of antibiotics in highly selected patients. After the resolution of AUD, emerging options are available to try to avoid persistent symptoms and recurrence. As our understanding of the disease continues to evolve, the management options will evolve as well. Although elective surgery is an effective treatment for diverticulitis, it should be offered on an individualized basis weighing risks and benefits in each specific patient.




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Acute diverticulitis; Uncomplicated diverticulitis; Outpatient management

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