Diverticular disease (DD) has long been considered a common disease in Western countries. Worldwide, the major incidence is found in the United States, Europe, and Australia, affecting 50% of the population over the age of 60 years, with a prevalence of 15% to 35% [1]. The lifetime risk of acute diverticulitis in someone with diverticulosis is 10% to 25% [2].

Diverticulitis is a heterogeneous disease in both presentation and prognosis. Uncomplicated diverticulitis is the most common presentation and is characterized by acute onset of diverticular inflammation without abscess or perforation [3]. Among gastrointestinal diseases, is a leading cause of ambulatory visits, hospital admissions, and colon surgery, accounting for substantial healthcare expenditures [4].

Besides the geographical variability in the prevalence of DD, there is significant variability in the location of colonic diverticula in different regions of the world [5]. According to reports in the West, it affects primarily the left side (90%) predominating in the sigmoid colon, whereas in Asia it mostly affects the right-sided colon (80%) with a prevalence of 8% to 25% [6, 7]. However, with increasing migration, it has recently been detected a major frequency of right-sided DD in the West [8]. These differences suggest that the pathophysiology of DD may differ between populations.

In the past decade, our understanding of diverticulitis has expanded substantially with the publication of multiple observational studies and clinical trials. Historically, diverticulitis was thought to be an aggressive disease, and the threshold for surgical intervention was low. With a better understanding of prognosis, a shift toward nonoperative approaches has occurred [3].

The purpose of this study was to describe our experience in right-sided acute diverticulitis, carried out in a Western university hospital.

The Western countries are characterized by having a heterogeneous population that has migrated from the East, so the incidence of DD might increase considerably in the future [5]. However, no studies have demonstrated an alignment in the incidence between the immigrants and the native population.

Argentina is considered as a “country of immigration,” in relation to the strong impact that various migratory flows have caused over the native composition of the population, especially of European origin, followed by American neighboring countries, and to a lesser extent Asian countries [9]. The 2010 census estimated that 3.4% of people of Asian descent lived in Córdoba [10] and this could explain why our study has no Asian patients.

Reports have indicated that RD incidence in Asian population is 55% to 70%, whereas in Caucasians is 1% to 2% [11]. In this series, the incidence in Caucasians was 3.2%, being above that reported in the literature. Besides, it is more frequent in males, with a male to female ratio of 2.0:1 to 3.2:1; and it affects mainly young population between 32 to 53.1 years old [11, 12]. Our findings were similar.

Pathologically, left-sided DD consists of pseudodiverticula and it has commonly been related to aging and a low dietary fiber intake, as risk factors [13]. On the other hand, the pathogenesis of DD is controversial and reports have indicated that they are congenital or “true” diverticula, with herniations that affect all the layers in the colonic wall and are not associated with aging [14]. In this cohort, the patients with RD were significantly younger than patients with LD, a fact that would support the theory that RD has a congenital nature.

The anatomic distribution of diverticula seems to vary according to race. In Caucasians, 75% are located in the sigmoid colon, 11% in the splenic flexure or descending colon, 6% in the transversal colon, and only 8% in ascending colon or hepatic flexure [15]. This study showed that 21.1% were located in splenic flexure or descending colon and 3.2% in the right-sided colon.

On a clinical basis, it is difficult to distinguish RD from appendicitis, due to the fact that signs and symptoms are similar at the moment of presentation, especially in young patients [16]; which requires a differential diagnosis between these 2 pathologies to determine a therapeutic plan and avoid unnecessary surgeries, due to a misdiagnosis of AA [17]. In this cohort, AA was suspected in 75% of the cases. However, only 3 patients required surgery.

Currently, few studies have reported differences between RD and appendicitis. It has been described that the prevalence of pain migration was significantly higher in AA (39.2%–82%) compared to that of RD (15.4%–54%) [18, 19]. In this cohort, 63% of patients with RD presented abdominal pain migration, similar to that reported. Also, it could be confused with other diseases such as cholecystitis, gastritis, or peptic ulcer, although less frequently [20, 21]. We found a patient with right hypochondrium pain who simulated cholecystitis, but without findings on biliary pathology ultrasound.

Among other differences existing with appendicitis, reports have indicated that the duration of abdominal pain is longer in RD (68.4±23.3 hours vs. 29.8±20.2 hours, P<0.01) [19]. In this work, the time interval from the onset of abdominal pain until admission was 47.3±10.2 hours, similar to the information reported in the literature.

On the other hand, reports indicate a low incidence of nausea and vomiting in RD (8%–16%) compared to AA (32%–72%) [18], which differs from our findings, since in this study 44% of patients with RD presented nausea and vomiting.

With regard to fever, it was reported that its prevalence is not significantly different between AA and RD (14.4% vs. 15.0%, P=0.87) [18], similar to our results.

From the analytical approach, reports show that leukocytosis in RD is in 58% to 69.2%; and in AA, it is presented in 68.5% to 90% [12, 22]. In this cohort, 94.0% of patients with RD presented a leukocyte count above 10.000×10⁹/L. However, the number of studies that have demonstrated its utility to differentiate both illnesses is limited, is this still a controversial topic.

In a recent study, we demonstrated the utility of NLR to predict complicated LD, with a cutoff point of ≥ 4.2 as the best value of diagnostic approximation [23]. Similarly, in this cohort we found that NLR showed statistical significance in relation to the severity of Hinchey stage, validating its applicability as a reliable, noninvasive, and cost-effective marker in the early diagnosis of complicated DD.

After the clinical and analytical evaluation, radiological images are required to continue the assessment of patients with right lower quadrant pain. Reports indicate that the ultrasound performed by an experienced radiologist for RD diagnosis shows a sensitivity of 91.3% and a specificity of 99.8% [24], but other studies have not confirmed this information. Our diagnosis rate using the ultrasound scan was very low (25.0%), similar to the results in other studies [12]. CT is another technique used in case of colonic diverticulitis suspicion, which presents a specificity of 90% to 95%, but in some cases, it may establish a wrong diagnosis and confuse RD with an appendicular abscess, Crohn disease, epiploic infarction, or colon cancer [21]. CT has been reported to presents a preoperative diagnosis rate in RD of 78.4% to 83.3% [25, 26]. According to our institutional protocol, we completed the tomographic evaluation in 87.5% of our patients, with a preoperative diagnosis rate of 93%.

There are no established guidelines for the treatment of RD, and current recommendations commonly refer to the left-sided colon. It was shown that RD patients are less likely to have serious complications and therefore more likely to respond to conservative treatment with less need for emergency surgery and shorter length of hospital stay [5]. In our study, we found that the rate of complicated diverticulitis was significantly lower in the group of patients with RD (6.3% vs. 12.5%, P=0.04). Furthermore, the conservative treatment was feasible in most patients due to the high rate of preoperative diagnosis.

The observed differences in disease severity between RD and LD may be explained by various factors. Inflammation in RD is more likely to be localized to a single diverticulum, while the inflammation in LD is commonly described as diffuse, involving multiple diverticula with wall thickening [27]. Anatomically most of the right colon is retroperitoneal which may limit the spread of inflammation, while the sigmoid colon, the most common site of LD, is intraperitoneal which may result in the easier spread of inflammation [28].

Although it varies by investigator, the recurrence rate in RD after conservative treatments is shown to be approximately 3% to 15% [22]. During the follow-up, only 1 patient was detected recurrence but had no complications and a presented good evolution with the conservative treatment.

There is controversy as to the surgical treatment for RD found at the moment of surgery. Mainly 4 surgical strategies can be considered; diverticulectomy with appendectomy, ileocecal resection, right hemicolectomy, and prophylactic appendectomy [16]. From the patients who required surgery, 1 underwent prophylactic appendectomy for severe local inflammation, while in the other 2 patients, the exploration laparoscopic detected diverticulitis of the ascending colon that did not require appendectomy. However, appendectomy, alone, could be associated with an increase in the rate of recurrence and the need for a new surgery since this approach does not offer a definite treatment for RD [12]. None of the 3 patients operated on did present recurrences, nor complications during the follow-up, but it is difficult to establish the true recurrence rate in patients operated, due to the fact that in our experience we had a predominance of cases treated conservatively.

The limitations of our study were its retrospective design and that a small number of patients with RD treated in a single center in Córdoba, Argentina were recruited. However, the RD is considered a rare pathology in our environment. In addition, risk factors for diverticulitis, including eating habits, physical activity, and defecation habits, were not included in our research. Therefore, the results of our study cannot be generalized to the entire population.

In our environment, the incidence and complication rate of RD are lower compared to LD. Conservative treatment predominated in RD. However, the evidence is very limited and further studies are required to provide robust data.