Outpatient Management of Acute Diverticulitis. Where is the Border?

Results: The failure rate was 22% (13 patients). 18,2% of the patients with pericolic air as sole finding on the initial CT-scan (grade IA WSES) needed surgical rescue, as well as 14,3% of the patients with small abscess (grade IB). On the former group failure of medical management was observed in 33,3% of pelvic abscesses. In the >4 cm abscess group (WSES IIA) the failure rate was 33,3%; 40% of them requiring percutaneous drainage. The mean time to surgical rescue was 7 days (IQR: 6-19,5 days).


Introduction
Colonic diverticulosis is primarily seen in the Western population with prevalence increasing with age. At 40 years of age, approximately 10% of the Western population has diverticulosis, while this number increases up to 70% in octogenarians [1][2][3].

Results
The 62,7% of the patients were women (37 patients) and the On the abscess > 4cm group (stage IIA) the failure rate was 33,3%, with no differences between pericolic abscesses or pelvic abscesses (30% vs 37,5% respectively; p=1). Of them, 40% needed percutaneous drainage. Both patients belonging to the stage IIB group (distant free gas), had a satisfactory response to medical treatment. The median time to surgical rescue was 7 days (IQR: 6-21 days). On the former group the median in-hospital stay was 22 days (IQR: 18 -33 days) versus 11,5 days on the group of patients who responded to medical management (p=0,045). There was no mortality associated to conservative management.

Discussion
Non-complicated acute diverticulitis episodes are usually satisfactorily medically managed. Classically, patients were hospitalized to receive intravenous antibiotherapy and fluid therapy.
Nevertheless, now a days, there is a tendency to opt for outpatient management, as it has been demonstrated in several randomized controlled trials in patients without major comorbidities [16][17][18][19][20][21][22]. In 2014 Biondo et al. [23] published the promising results of the DIVER trial, that demonstrated the efficacy of outpatient treatment of noncomplicated acute diverticulitis and its reduction of sanitary costs.
These findings were endorsed by several systematic reviews were a reduction of up to 80% on sanitary costs was observed, without influencing the results of this kind of therapy [24]. Nevertheless, we should not get carried away by optimism, because the success of this treatment relies on a careful patient selection. Thus, we should be cautious when prescribing an outpatient management for patients with extraluminal air o abscesses. Given the different modifications on the original Hinchey classification, the presence of extraluminal pericolic air or small (< 2-3cm) pericolic abscesses has been considered as non-complicated acute diverticulitis, being these forms suitable for ambulatory management depending on the authors [25,26].
The clinical relevance of the presence of extraluminal air on the diagnostic CT-scan without peritonism or signs of sepsis remains controversial [1]. Titos-García et al. [27] and Salinnen et al. [28] published their results regarding the medical treatment of patients with pericolic air, obtaining success rates of 90% and 99% respectively. In our study, both extraluminal air and pericolic abscess (independently from size) were considered complicated forms of acute diverticulitis, following the classification proposed by WSES on 2016 [29], excluding them from the current outpatient management protocol established in 2016, which has demonstrated to date an efficacy greater that 94%. The decision of maintaining such exclusion criteria is based on the results obtained on the present study. As previously said, we observed that patients with beforehand favorable clinical presentations finally required urgent surgery given the failure of conservative management in a significative percentage of cases. It is noteworthy that 1 out of 5 patients only with extraluminal air or that up to 10% of small pericolic abscesses needed surgical rescue, which were categories defined as "non-complicated" by some authors. Thus, even if the efficacy and safety of outpatient management of simple acute diverticulitis has been widely demonstrated, as well as its reduction of sanitary costs, it is not a therapeutic regimen that can be universally prescribed, being an adequate patient selection the main success factor. That is why we should be cautious when including on this treatment modality some cases which classification as noncomplicated could be controversial. Main limitations of this study are the small simple of patients and its retrospective character.
More prospective and randomized studies are needed to establish the best and safest treatment for these patients. Until we have consistent evidence and based on our own experience, given the high failure rates of medical treatment, to preserve our patients' security, we recommend limiting outpatient management to cases of simple acute diverticulitis, namely the absence of any sing of complication such as extraluminal air or abscesses, independently from size or location.