Diverticulitis Staging Systems
Multiple classification systems exist for acute diverticulitis, with no single system proven superior, but the WSES CT-guided classification and Modified Hinchey classification are the most practical for guiding contemporary management decisions. 1
Primary Classification Systems
WSES CT-Guided Classification (Recommended for Daily Practice)
The World Society of Emergency Surgery classification divides acute diverticulitis into two main categories based on CT findings: 1
Uncomplicated Diverticulitis:
- Stage 0: Diverticula, wall thickening, increased pericolic fat density (infection confined to colon, no peritoneal extension) 1
Complicated Diverticulitis:
- Stage 1A: Pericolic air bubbles or small pericolic fluid without abscess (within 5 cm of inflamed bowel) 1
- Stage 1B: Abscess ≤ 4 cm 1
- Stage 2A: Abscess > 4 cm 1
- Stage 2B: Distant gas (> 5 cm from inflamed bowel segment) 1
- Stage 3: Diffuse fluid without distant free gas 1
- Stage 4: Diffuse fluid with distant free gas 1
Modified Hinchey Classification (Traditional, Most Widely Used)
The Hinchey classification has been the international standard for three decades, modified by Kaiser et al. to incorporate CT findings: 1
- Stage 0: Mild clinical diverticulitis 1
- Stage 1a: Confined pericolic inflammation 1
- Stage 1b: Confined pericolic abscess 1
- Stage 2: Pelvic or distant intra-abdominal abscess 1
- Stage 3: Generalized purulent peritonitis 1
- Stage 4: Fecal peritonitis 1
Sallinen Classification (Incorporates Organ Dysfunction)
This system integrates clinical, radiologic, and physiologic parameters, uniquely accounting for organ dysfunction which significantly impacts mortality: 1, 2
- Stage 1: Uncomplicated diverticulitis 1
- Stage 2: Complicated diverticulitis with small abscess (< 6 cm) 1
- Stage 3: Complicated diverticulitis with large abscess (≥ 6 cm) or distant intraperitoneal/retroperitoneal gas 1
- Stage 4: Generalized peritonitis without organ dysfunction 1
- Stage 5: Generalized peritonitis with organ dysfunction 1
The Sallinen classification demonstrates superior predictive ability for mortality (0%, 1%, 3%, 4%, and 32% for stages 1-5 respectively) and need for surgery (1%, 5%, 46%, 98%, and 100% for stages 1-5 respectively). 2
Clinical Application and Management Implications
CT imaging is essential for accurate staging and should not be omitted—clinical examination alone is insufficient for diagnosis and classification. 3, 4, 5
Treatment Based on Staging:
- Small abscesses (< 4 cm, Hinchey 1b): Non-operative management with bowel rest and antibiotics 3, 4
- Larger abscesses (> 4 cm, Hinchey 2): Percutaneous drainage recommended 3, 4
- Abscesses ≥ 3-4 cm: Percutaneous drainage indicated 5
- Generalized peritonitis (Hinchey 3-4): Surgical intervention required 6
Important Caveats
No classification system has been conclusively proven superior in predicting patient outcomes, so the choice should be based on institutional familiarity and whether preoperative or intraoperative assessment is being performed. 1
The WSES classification is simpler and more practical for day-to-day emergency practice, while the Sallinen classification provides better prognostic information when organ dysfunction is present. 1, 2 The Modified Hinchey remains the most internationally recognized system for research and communication between institutions. 1
Avoid relying solely on clinical findings—the distinction between complicated and uncomplicated disease, and between Hinchey stages 3 and 4, requires CT imaging or laparoscopy/laparotomy. 1, 6