Hinchey Classification for Acute Diverticulitis
The Hinchey classification is the most widely used staging system for acute colonic diverticulitis that stratifies disease severity from pericolic abscess to fecal peritonitis, directly guiding treatment decisions from conservative management to emergency surgery. 1
Original Hinchey Classification
The original system, developed over three decades ago, categorizes surgical findings into four progressive stages 1:
- Stage 1: Pericolic abscess
- Stage 2: Pelvic, intra-abdominal, or retroperitoneal abscess
- Stage 3: Generalized purulent peritonitis
- Stage 4: Fecal peritonitis
Modified Hinchey Classification (Kaiser 2005)
The modified version incorporates CT imaging findings for more precise preoperative diagnosis 1, 2:
- Stage 0: Mild clinical diverticulitis
- Stage 1a: Confined pericolic inflammation
- Stage 1b: Confined pericolic abscess
- Stage 2: Pelvic or distant intra-abdominal abscess
- Stage 3: Generalized purulent peritonitis
- Stage 4: Fecal peritonitis at presentation
Treatment Algorithm Based on Hinchey Stage
Hinchey 1b (Small Pericolic Abscess <4 cm)
- Non-operative management with bowel rest and antibiotics 3, 4, 5
- CT imaging is mandatory for accurate staging 4, 5
- Failure rate of conservative treatment is 6.8% for uncomplicated cases but increases to 22.2% when abscess is present 2
Hinchey 2 (Larger Abscess >4 cm)
- Percutaneous CT-guided drainage is the treatment of choice 3, 4, 5
- Success rate is high, with only one failure requiring two-stage operation in one series 2
- Recurrence rates after conservative treatment with or without drainage reach 41.2% for pelvic abscesses 2
Hinchey 3 (Purulent Peritonitis)
- Surgical intervention is required 5, 6
- Laparoscopic peritoneal lavage may be considered in select patients with similar mortality and major morbidity rates compared to resection, though higher postoperative abscess and early reintervention rates exist 6
- Resection with primary anastomosis achieved in 73.6% of surgical cases with 1.1% perioperative mortality and 2.1% leak rate 2
Hinchey 4 (Fecal Peritonitis)
- Emergency surgical resection is mandatory 5, 6
- High-associated morbidity and mortality 6
- Up to 35% of patients presenting with diverticulitis will have Hinchey III or IV disease 6
Critical Clinical Pitfalls
Never rely on clinical examination alone for diagnosis and staging 4, 5. CT imaging is essential for accurate classification and management planning, as clinical examination has poor accuracy 4.
Strongly consider elective surgery after treatment of CT-documented abscess 2. Patients with CT evidence of abscess have high risk of recurrence (41.2% for pelvic abscess) and failure of nonoperative management regardless of age 2.
Alternative Classification Systems
While multiple classification systems exist (Mora Lopez, Sallinen, WSES CT-guided), no system has been conclusively proven superior in predicting patient outcomes 1. The Hinchey classification remains the international standard due to its three-decade track record and widespread adoption 1.
The AAST grading scale has been shown equivalent to modified Hinchey in predicting procedural intervention (c-statistic 0.83 vs 0.80) and complications (c-statistic 0.83 vs 0.80), with the advantage of preoperative application 7.