Epidemiology, Pathophysiology, and Treatment of Diverticulitis

Abstract

Diverticulitis is a prevalent gastrointestinal disorder that is associated with significant morbidity and health care costs. Approximately 20% of patients with incident diverticulitis have at least 1 recurrence. Complications of diverticulitis, such as abdominal sepsis, are less likely to occur with subsequent events. Several risk factors, many of which are modifiable, have been identified including obesity, diet, and physical inactivity. Diet and lifestyle factors could affect risk of diverticulitis through their effects on the intestinal microbiome and inflammation. Preliminary studies have found that the composition and function of the gut microbiome differ between individuals with vs without diverticulitis. Genetic factors, as well as alterations in colonic neuromusculature, can also contribute to the development of diverticulitis. Less-aggressive and more-nuanced treatment strategies have been developed. Two multicenter, randomized trials of patients with uncomplicated diverticulitis found that antibiotics did not speed recovery or prevent subsequent complications. Elective surgical resection is no longer recommended solely based on number of recurrent events or young patient age and might not be necessary for some patients with diverticulitis complicated by abscess. Randomized trials of hemodynamically stable patients who require urgent surgery for acute, complicated diverticulitis that has not improved with antibiotics provide evidence to support primary anastomosis vs sigmoid colectomy with end colostomy. Despite these advances, more research is needed to increase our understanding of the pathogenesis of diverticulitis and to clarify treatment algorithms.

Keywords: Chronic Manifestations; Functional Symptoms; Immunosuppression; Laparoscopic Lavage; Smoldering Diverticulitis.

Figure 1.

Natural history of diverticulosis and diverticulitis. aThe majority of complications occur during the first or second episode of diverticulitis.^, bEstimates of recurrence are for all patients with diverticulitis regardless of the presence of complications and in the absence of prophylactic surgery. Of note, patients with complicated diverticulitis treated medically do not appear to be at increased risk of recurrent diverticulitis compared with uncomplicated diverticulitis. However, the risk of recurrence is significantly lower in those who undergo surgery for complicated diverticulitis.

Figure 2.

Proposed pathophysiology of acute colonic diverticulitis. Diverticulitis is hypothesized to arise from the complex interaction of diet and lifestyle factors, medications, genetics, and the gut microbiome. Alterations in the gut microbiome composition (eg, ↓short chain fatty acid, SCFA, producers, ↑invasive pathogens) and function (↓SCFAs, altered bile acids) result in defects in the mucosal barrier and immune function leading to an inflammatory cascade and mucosal inflammation.

Figure 3.

Management algorithm for acute diverticulitis. Evaluation and treatment approach depends on the severity of presentation, presence of complications (peritonitis, abscess), and comorbid conditions. aLow-risk presentation includes no markedly elevated WBC, CRP, or temperature, no signs of sepsis or peritonitis, no immunocompromise or significant comorbid disease. bSuch as a pelvic abscess. cRecommended by current guidelines, but some evidence to suggest good outcomes without resection in selected patients. CRP, C-reactive protein; IV, intravenous; PO, per os; WBC, white blood cell count.