Management and Evolution of Acute Diverticulitis With Pericolic Free Gas
Management and Evolution of Acute Diverticulitis With Pericolic Free Gas
The severity of diverticulitis is usually graded with the use of modified Hinchey Criteria.
 However, there is a condition often seen in the CT scan that is not included in this
 classification itself; 1-2 pericolic bubbles but no free air or fluid into the abdomen or
 above the liver. Outcome in these patients remains unknown. We aim to analyse the treatment
 that these patients and their evolution over the first year after the diagnosis in order to
 predict the disease related outcome.

 The study is set up as a retrospective multicentre observational study. Inclusion criteria
 are Patients over 18 years old, Diagnosed of acute diverticulitis with a CT scan reported as
 1-2 pericolic bubbles with or without free fluid. Exclusion criteria: 1) CT scan showing free
 distant bubbles in the abdomen. 2) CT scan showing abscess.

 Accepting an alpha risk of 0.05 and a beta risk of 0.2 in a two-sided test, 137 subjects are
 necessary in the observed group to recognize a difference in morbidity greater than or equal
 to 10%. A proportion in the reference group has been estimated to be 20%. It has been
 anticipated a drop-out rate of 0%.

 Primary outcome is 30-day morbidity and mortality. Secondary outcomes include malignancy and
 1 year morbidity including recurrences and ongoing disease. Data will be collected in an
 online repository. The CT scans will be reviewed by 2 experienced independent radiologists.
 The management of these patients at the moment of the diagnosis will be recorded, as well as
 their evolution over the first year during the outpatient clinics. Figure 1 represents the
 study flow chart.

 Data will be collected in an online secure and protected repository (Castor edc). The planned
 study period is 2 years (01/06/2020 - 31/12/2021).

 CT scans will be reviewed by 2 experienced radiologists. Every other CT scan performed during
 the follow-up will be reviewed by the same radiologists.

 The management of these patients at the moment of the diagnosis will be recorded, as well as
 their evolution over the first year during the outpatient clinics.

 This study protocol is a new approach to an unknown entity in diverticulitis. We are convince
 that the outcomes are clinically relevant to patients and interesting for all physicians
 treating diverticulitis.
Diverticular disease of the colon is a common disease that includes diverticulosis and
 diverticulitis. Most patients who have diverticulosis remain asymptomatic; however an
 estimated 15-20% will develop acute diverticulitis (AD).(1) AD is an inflammatory condition
 affecting at least one colonic diverticula, often associated with pericolonic
 inflammation.(2) Diverticulitis can range form mild to severe. Severe, complicated cases with
 perforation may be associated with intra-abdominal abscess, generalized, purulent
 peritonitis, fistula formation, bleeding or obstruction. The extent of the perforation
 determines the clinical behavior. Microperforations remain localised because they are
 contained by pericolic fat and mesentery, leading to the formation of small pericolic
 abscesses.

 The gold standard for the diagnosis of diverticulitis is the Computed Tomography (CT). It has
 a sensitivity ranging form 85% to 97% (3,4) and it is very accurate identifying colonic
 perforation, which can have a direct impact on the management of the patient. The severity of
 diverticulitis is usually graded with the use of modified Hinchey's Criteria, based on CT
 imaging and on preoperative findings.(5) It distinguishes four stages of acute complicated
 diverticulitis. Several modifications to the Hinchey classification have been proposed due to
 the advancements in imaging modalities. New subcategories have been added that take
 radiological findings into consideration.(6) However, there is a condition often seen in the
 CT scan that is not included in this classification itself; a single pericolic bubble.

 The management of AD depends on its severity and complexity, and it requires hospitalization,
 bowel rest and surgery in selected cases. Antibiotic therapy is part of the management of
 complicated diverticulitis and recent guidelines are in accordance at recommending
 broad-spectrum antibiotics. Biondo and colleagues evaluated 92 papers in a systematic review,
 concluding that patients with severe AD without need of emergency surgery, should be treated
 with hospitalization, parenteral fluids and a single intravenous antibiotic active against
 aerobic and anaerobic bacteria.(7) Approximately 15-20% of patients admitted with AD have an
 abscess on CT scan.(8) The size of 3-6 cm has been generally accepted to be treated with
 antibiotics vs. percutaneous drainage.(8-10) However, clinical monitoring is mandatory and a
 CT scan should be repeated if the patient does not show clinical and laboratory improvement.

 In the 1990s laparoscopic lavage (LL) was proposed to treat patients affected by peritonitis
 due to perforated AD.(11) Initial results encouraged surgeons to perform LL;(12-14) however,
 in the 2000s three Randomized Control Trials (RCT) were published with mixed results.(15-17)
 Two of them suggested that the traditional surgical treatment (segmental resection and stoma
 formation) achieves more successful results.(16,17) In summary, there are several guidelines
 for the treatment of AD regarding its severity; however, there is no consensus in the
 management of those patients with 1-2 pericolic bubbles but no free air into the abdomen. The
 treatment that these patients receive is widely variable.

 For this reason, patients admitted in the emergency unit and diagnosed of acute
 diverticulitis with a free pericolic bubble of air, regardless the Hinchey's criteria
 assigned and the treatment received, would be included in this study. We aim to analyse the
 treatment that they underwent and the evolution of these patients over the first year after
 the diagnosis. The patients will not undergo any treatment or test that would not be
 necessary during their follow-up out of this observational and retrospective study.
Inclusion Criteria:

 -  Patients over 18 years old

 -  Informed consent

 -  Diagnosed of acute diverticulitis

 -  CT scan reported as 1-2 pericolic bubbles with or without free fluid.

 Exclusion Criteria:

 -  CT scan showing free distant bubbles in the abdomen

 -  CT scan showing abscess