Acute Diverticulitis
Executive Summary
Acute diverticulitis (AD) is a common complication of diverticular disease, affecting approximately 15–25% of individuals with diverticulosis. Traditionally a condition associated with Western nations, its global prevalence is rising due to shifting lifestyle factors. Computed Tomography (CT) with intravenous contrast has emerged as the definitive "gold standard" for diagnosis, offering sensitivity and specificity rates as high as 98% and 99%, respectively.
The clinical management of AD has evolved significantly through various classification systems—most notably the Neff, Sher, Ambrosetti, and Kaiser modifications of the Hinchey classification. Currently, the 2015 World Society of Emergency Surgery (WSES) classification provides a streamlined framework that categorizes AD into "uncomplicated" and "complicated" stages. A critical shift in recent clinical consensus suggests that uncomplicated AD (Stage 0) may be a self-limiting condition, potentially manageable without antibiotics in immunocompetent patients and suitable for outpatient care in the absence of comorbidities.
Disease Overview and Epidemiology
Diverticular disease remains highly prevalent in Western countries, with an increasing global footprint attributed to lifestyle changes. Acute diverticulitis represents a spectrum of clinical severity, ranging from localized, uncomplicated inflammation of the colonic wall to life-threatening fecal peritonitis.
Prevalence: 15–25% of patients with diverticulosis will develop acute diverticulitis.
Pathology: The condition encompasses a variety of inflammatory states, from confined pericolic inflammation to the presence of distant abscesses and generalized peritonitis.
The Role of Computed Tomography (CT)
CT imaging is essential not only for the accurate diagnosis of AD but also for staging and treatment planning.
Diagnostic Efficacy
Gold Standard: CT with intravenous contrast is the preferred imaging modality.
Accuracy: Reported sensitivity of 98% and specificity of 99%.
Clinical Utility
Beyond simple diagnosis, CT scans allow clinicians to:
Assess the grade of severity.
Drive treatment planning (e.g., identifying cases suitable for percutaneous drainage).
Identify specific radiological markers such as wall thickening, pericolic fat stranding, extraluminal air, or contrast leaks.
Evolution of Classification Systems
Over the last several decades, the detailed information provided by CT scans has led to several modifications of the original Hinchey classification system.
WSES Classification System (2015)
The World Society of Emergency Surgery introduced a simplified classification system to guide clinical decision-making. This system bifurcates the disease based on whether the infectious process is confined to the colon.
Uncomplicated Diverticulitis
Stage 0: Inflammation is confined to the colon. CT markers include diverticula, colonic wall thickening, and increased density of the pericolic fat.
Complicated Diverticulitis
The infectious process extends beyond the colon, categorized into four primary stages:
Management Trends and Clinical Conclusions
The integration of CT staging into clinical practice has led to a more nuanced approach to treatment, particularly regarding the use of antibiotics and hospitalization.
Self-Limiting Nature: Recent international literature suggests that in immunocompetent patients, local host defenses may be sufficient to manage the bacterial inflammation of uncomplicated AD (Stage 0).
Antibiotic Stewardship: Evidence indicates that antibiotics may not be strictly necessary for the treatment of uncomplicated disease.
Outpatient Management: For patients diagnosed with uncomplicated AD (Stage 0) who present with no significant comorbidities, outpatient management is now a suggested clinical pathway.
Interventional Radiology: Modern classifications (such as Sher et al.) specifically account for the u se of CT-guided percutaneous drainage as a primary treatment strategy for certain abscess stages, reducing the immediate need for invasive surgery.
