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American Gastroenterological Association guideline advises against routine antibiotic use in uncompl


-Acute diverticulitis: clinically evident macroscopic inflammation of a diverticulum or diverticula,

-Rate of acute diverticulitis~4% of patients with diverticulosis;

of these~15% of those patients will have complicated disease, ---complicated disease-defined as an abscess, perforation, fistula, or colonic obstruction,

Of those with complicated disease-Approx~15% to 30% will experience recurrence.


  1. Guideline does not address other manifestations of diverticular disease, such as:

  • Symptomatic uncomplicated diverticular disea

  • Diverticular bleeding,

  • Segmental colitis associated with diverticulosis,

  1. Guideline does not examine the prevention of incident diverticulitis or the management of complicated disease.

  2. The definition requires a CT scan that documents the lack of abscesses or fistulas. Patients with clinical findings of severe infection or sepsis have complicated diverticulitis.

  3. Patients with risk factors for more severe disease, such as immunosuppression, or significant comorbidities do not fit the definition. This guideline does not apply to those more complicated patients.

Some questions in guideline has direct impact on the use of inpatient and outpatient antibiotics these include

Question 1. Should Antibiotics Be Routinely Used in Patients With Acute Uncomplicated Diverticulitis?

AGA suggests that antibiotics should be used selectively, rather than routinely, in patients with acute uncomplicated diverticulitis. This is based on emerging belief that acute diverticulitis may be more inflammatory than infectious.

Caveats-again exercise caution in the immune compromised and complicated patients –those that are hemodynamically unstable with febrile or septic pictures and markedly abnormal abdominal exams

Two recent randomized trials and 2 systematic reviews have reported no clear benefit and questioned the routine use of antibiotics, as does this guideline, suggesting selective and individualized use.


  1. Current data are of low quality, and recommendations could change as further studies are performed.

  2. Patients studied were inpatients with uncomplicated disease confirmed by computed tomography (CT);

  3. Results should not be generalized to complicated patients defined as those with

  • abscesses or fistulas

  • signs of severe infection or sepsis

  • immunosuppression

  • other significant comorbidities.

  1. Additionally, outpatient management without antibiotics has not been studied, although these presumably have generally milder disease and logically equal or better outcomes.

In addition to above

Question 9: AGA suggests against the use of rifaximin after acute uncomplicated diverticulitis.

Question 10: AGA suggests against the use of probiotics after acute uncomplicated diverticulitis.

Per Dr Centor Commenting on these Guidelines in the Annals of Internal medicine:

"Uncomplicated diverticulitis prompts most internists almost reflexively to prescribe antibiotics, either outpatient or inpatient, depending on a subjective assessment of the patient's condition. Recent articles have challenged this concept, suggesting that most acute uncomplicated diverticulitis is an inflammatory reaction rather than an acute infection."

Isacson M et al: 155 patients with acute uncomplicated diverticulitis received conservative outpatient management without antibiotics (3). Only 4 (2.6%) patients required admission: 3 for complications and 1 for deterioration. All 4 had successful inpatient treatment without the need for surgery.

A randomized, controlled trial published in 2012 studied 623 patients with acute uncomplicated diverticulitis confirmed via computed tomography: 314 patients received antibiotics and 309 patients did not. (4)The investigators found no statistical difference in length of hospitalization (3 days), perforation or abscess formation, or recurrent diverticulitis within 1 year (16%).



  1. Stollman N, Smalley W, Hirano I. AGA Institute Clinical Guidelines Committee. American Gastroenterological Association Institute Guideline on the Management of Acute Diverticulitis.Gastroenterology.2015.

Dr Centor's Comments in Annals:

  1. Centor RM. Acute Uncomplicated Diverticulitis: What to Do Until We Have Better Data. Ann Intern Med. 2016;164:120-121. doi: 10.7326/M15-2499

These studies suggest other than antibiotic treatment:

  1. Isacson D, Thorisson A, Andreasson K, Nikberg M, Smedh K, Chabok A: Outpatient, Non-antibiotic management in acute uncomplicated diverticulitis: a prospective study.Int J Colorectal Dis 2015;30:1229-34.

  2. Chabok A, Påhlman L, Hjern F, Haapaniemi S, Smedh K, AVOD Study Group Randomized clinical trial of antibiotics in acute uncomplicated diverticulitis.Br J Surg 2012;99:532-9

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