What is sigmoid diverticulitis?

Sigmoid Diverticulitis: Definition, Diagnosis, and Management

Sigmoid diverticulitis is an inflammatory condition affecting diverticula in the sigmoid colon, characterized by localized inflammation, potential perforation, and varying degrees of severity that may require medical or surgical intervention depending on the clinical presentation. 1

Definition and Pathophysiology

• Sigmoid diverticulitis occurs when diverticula (small pouches that form in the wall of the sigmoid colon) become inflamed or infected 1
• It is a common condition in Western populations, with the sigmoid colon being the most commonly affected segment of the colon 1
• The condition represents a complication of diverticulosis, with approximately 4% of patients with diverticulosis developing diverticulitis during their lifetime 1
• Pathogenesis involves inflammation of diverticula, which can lead to microperforation, abscess formation, or frank perforation in more severe cases 1

Epidemiology

• Sigmoid diverticulitis is predominantly a disease of Western societies, strongly related to lifestyle habits, particularly high-fat diet and alcohol consumption 1
• Up to one-fifth of patients with acute diverticulitis in Western populations are under 50 years of age 1
• The prevalence of diverticulosis increases with age, from 32.6% in patients aged 50-59 years to 71.4% in patients aged 80 years 1
• The prevalence is historically lower in Africa and parts of Asia but appears to be increasing with the adoption of Western dietary habits 1

Clinical Presentation

• Typical symptoms include acute pain or tenderness in the left lower quadrant 1
• May be associated with increased inflammatory markers including C-reactive protein (CRP) and elevated white blood cell count 1
• Fever, nausea, vomiting, and changes in bowel habits may also be present 1
• Clinical diagnosis alone lacks accuracy, with positive predictive value of only 0.65 1

Diagnosis

• CT scanning is considered the best overall imaging modality for diagnosing sigmoid diverticulitis, with sensitivity of 99% and specificity of 84% 1
• Ultrasound is a reasonable alternative, especially in resource-limited settings, with sensitivity of 90% and specificity of 90% 1
• Ultrasound features include diverticular wall thickening, surrounding echogenic fat, and intra-diverticular echogenic material 1
• Ambiguous ultrasound findings should be complemented with contrast-enhanced CT 1

Classification

• Diverticulitis is generally divided into uncomplicated and complicated forms 1
• Complicated diverticulitis includes abscess formation, perforation, fistula, or stricture 1
• The Hinchey classification system is commonly used to grade the severity of perforated diverticulitis:
  • Hinchey I: Confined pericolic abscess
  • Hinchey II: Pelvic abscess
  • Hinchey III: Purulent peritonitis
  • Hinchey IV: Fecal peritonitis 1

Management

Uncomplicated Diverticulitis

• Antibiotics can be avoided in patients with CT findings of uncomplicated diverticulitis who do not have significant comorbidities or signs of sepsis 1
• Clinical monitoring is essential to assess resolution of the inflammatory process 1
• When antibiotics are used, they should cover Gram-positive, Gram-negative, and anaerobic bacteria 1
• Discontinuation of antibiotic treatment should occur at 4 days from source control, as this has been demonstrated as non-inferior to longer therapy 1

Complicated Diverticulitis

• For localized abscesses, percutaneous drainage may be appropriate 1
• For perforated diverticulitis with generalized peritonitis (Hinchey III or IV), emergency surgery is typically required 1
• Surgical options include:
  • Hartmann procedure (sigmoid resection with end colostomy)
  • Primary anastomosis with or without diverting ileostomy 1
• Recent evidence suggests primary anastomosis may have better outcomes for stoma-free survival compared to Hartmann procedure (94.6% vs. 71.7%) 1
• Laparoscopic approaches may be feasible in stable patients with purulent or fecal peritonitis 1
• Damage control surgery with staged laparotomies may be appropriate in unstable patients with diffuse peritonitis 1

Recurrent Diverticulitis and Elective Surgery

• Elective sigmoid resection is indicated for recurrent diverticulitis, manifest stenosis, fistula formation, or in patients under 50 years after the first episode 2
• Elective surgery is typically performed laparoscopically when possible 2
• Quality of life appears improved by elective surgery in patients with recurrent episodes 3
• Following Hinchey I/II sigmoid diverticulitis, elective surgery may improve quality of life despite a 10% risk of postoperative complications 3

Segmental Colitis Associated with Diverticulosis (SCAD)

• SCAD is defined as a chronic inflammatory process confined to a diverticular segment, almost exclusively affecting the sigmoid colon 1
• It presents with Crohn's colitis-like changes (fissuring ulcers, granulomas, transmural lymphoid aggregates) 1
• By definition, both the rectum and proximal colon are endoscopically and histologically normal in SCAD 1
• The pathogenesis is unclear, but an idiosyncratic inflammatory response to diverticular disease has been suggested 1

Prognosis

• Following uncomplicated sigmoid diverticulitis, long-term quality of life does not substantially differ between patients treated with antibiotics versus those receiving only symptomatic treatment 3
• Properly performed elective sigmoid resection can effect a definitive cure with low morbidity and mortality 2
• Emergency surgery carries higher risks but appears not to have a greater impact on quality of life than elective surgery 3