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Diverticular Disease [Sabiston]

Background

  • Diverticular disease: A spectrum of manifestations associated with colonic diverticulosis.
  • Diverticula: Saccular outpouchings of the bowel wall.
    • True diverticula: Contain all layers of the bowel wall (rare, usually congenital).
    • False diverticula (pseudodiverticula): Contain only the mucosa and muscularis mucosa; these are the vast majority in the colon.
  • Modern Disease: Linked to dietary changes post-industrial revolution.

Pathophysiology and Epidemiology

Pathophysiology

  • Muscular Hypertrophy: Thickening of muscular layers of the colon wall.
  • Narrowed Lumen and Disordered Motility: Leads to localized high-pressure zones.
  • Herniation Sites: Occur where vasa recta penetrate the muscular layer on the mesenteric side.
  • Common Locations:
    • Sigmoid and descending colon are typically affected.
    • Rectum is generally spared due to an extra muscle layer.
    • Surgical Implication: Distal anastomosis in surgery should be within the rectum to prevent recurrence.

Epidemiology

  • Age-Related Prevalence:
    • 40% in individuals aged 50-60 years.
    • Over 60% in individuals over 80 years.
  • Diverticulitis Development:
    • Less than 5% of patients with diverticulosis develop diverticulitis.
  • Pathogenesis of Diverticulitis:
    • Obstruction of diverticulum orifice leads to:
      • Stasis and bacterial overgrowth
      • Inflammation and increased pressure
      • Ischemia and microperforation

Diet and Lifestyle Factors

  • Increased Risk:
    • Diet high in red meat, fat, and refined grains.
    • Central obesity.
    • Smoking.
  • Decreased Risk:
    • High fiber intake: Fruits, vegetables, whole grains.
    • Physical activity: Running and vigorous exercise.
    • Nuts, seeds, and popcorn: Do not increase risk.
  • Preventive Lifestyle:
    • Adherence to a low-risk lifestyle may prevent 50% of incident diverticulitis.

Clinical Evaluation

Presentation

  • Abdominal Pain: Localized to the left lower quadrant.
  • Associated Symptoms:
    • Fever
    • Change in bowel habits
    • Anorexia
    • Urinary urgency (if bladder is involved)
  • Physical Examination:
    • Localized tenderness
    • Possible tender mass (phlegmon)
    • Moderate abdominal distension
  • Laboratory Findings:
    • Leukocytosis is common.
  • Rectal Bleeding:
    • Rare in diverticulitis; suggests other diagnoses like ischemic colitis or inflammatory bowel disease (IBD).

Imaging Studies

  • Computed Tomography (CT) Scan:

    • Most useful diagnostic tool.
    • Identifies:
      • Diverticula
      • Colonic wall thickening
      • Pericolic fat stranding
      • Abscess formation
    • Helps classify severity using the Modified Hinchey Classification.

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  • Other Modalities:

    • Plain films: Detect obstruction or free air but are nonspecific.
    • Ultrasound and MRI: Alternative options.

  • Flexible Endoscopy:

    • Should be used with caution during acute diverticulitis due to risk of perforation.

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Modified Hinchey Classification

  • Stage 0: Mild clinical diverticulitis.
  • Stage Ia: Confined pericolic inflammation (phlegmon).
  • Stage Ib: Confined pericolic or mesocolic abscess.
  • Stage II: Pelvic, distant intraabdominal, or retroperitoneal abscesses.
  • Stage III: Generalized purulent peritonitis.
  • Stage IV: Fecal peritonitis.

Management

Complicated Diverticulitis

Defined by the presence of an abscess, fistula, obstruction, or free perforation.

Abscess

  • Diagnosis: Typically via imaging (CT scan).
  • Management:
    • Small Abscesses (<4 cm):
      • May be treated successfully with antibiotics alone.
    • Larger Abscesses:
      • Require percutaneous drainage.
      • Elective surgery is generally recommended after recovery.
    • Unresponsive Abscesses:
      • Require urgent surgery if not amenable to drainage or if patient deteriorates.

Fistula

  • Definition: Abnormal connection between the colon and another epithelial-lined organ.
  • Common Types:
    • Colovesical Fistula:
      • More common in men.
      • Symptoms: Recurrent urinary tract infections (UTIs), pneumaturia, fecaluria.
      • Diagnosis: CT scan showing air or contrast in bladder; cystoscopy.
    • Colovaginal Fistula:
      • Occurs in women, typically post-hysterectomy.
      • Symptoms: Vaginal discharge, passage of air via vagina.
    • Colocutaneous Fistula:
      • Presents at previous drain sites.
  • Management:
    • Initial Treatment:
      • Broad-spectrum antibiotics to reduce inflammation.
    • Investigations:
      • Colonoscopy to exclude malignancy and Crohn's disease.
      • Appropriate imaging (e.g., cystoscopy).
    • Surgical Intervention:
      • Resection of involved colon segment and fistula tract.
      • Primary anastomosis of healthy bowel.
      • Repair of fistula opening in secondary organ when feasible.
      • Bladder Fistulas:
        • Foley catheter drainage postoperatively to aid healing.

Obstruction

  • Cause: Fibrosis and stricture formation from recurrent inflammation.
  • Presentation:
    • Partial Obstruction: Gradual onset, partial blockage of colon.
    • Small Bowel Obstruction: Due to adhesions from inflamed colon.
  • Management:
    • Partial Obstruction:
      • Conservative treatment: Nasogastric decompression, antibiotics, fluids, bowel rest.
      • Elective surgery planned after resolution.
      • Colonoscopy prior to surgery to rule out malignancy.
    • Complete Obstruction:
      • Emergency surgery if unresponsive to conservative therapy.

Perforation

  • Presentation:
    • Diffuse peritonitis: Rebound tenderness, guarding.
    • Signs of Sepsis: Fever, tachycardia, hemodynamic instability.
  • Imaging:
    • CT scan showing free air, fluid, signs of peritonitis.
  • Management:
    • Emergency Surgery:
      • Hartmann Procedure:
        • Resection of diseased segment with creation of an end colostomy.
        • Reversal rates are low due to morbidity of second surgery.
      • Resection with Primary Anastomosis and Diverting Ileostomy:
        • Safe alternative with higher rates of stoma reversal (94%–96%).
      • Laparoscopic Lavage:
        • Considered for Hinchey Stage III (purulent peritonitis).
        • Controversial due to higher rates of recurrent sepsis and reoperations.

Uncomplicated Diverticulitis

  • Management:
    • Outpatient Treatment for most patients.
    • Pain Management and diet modification:
      • Start with clear liquids, progress to low-residue diet.
    • Antibiotics:
      • Traditionally used, but recent evidence suggests they may not be necessary in all cases.
  • Follow-Up:
    • Colonoscopy after 4–8 weeks to exclude malignancy (risk of misdiagnosis is 1%–3%).
  • Elective Surgery:
    • Decision is individualized based on:
      • Frequency and severity of attacks.
      • Impact on quality of life.
      • Patient's age and comorbidities.
    • Surgical Aim:
      • Resection of affected segment (usually sigmoid colon).
      • Primary anastomosis to healthy bowel.
      • Proximal margin: In soft, pliable bowel (not necessary to remove all diverticula).
      • Distal margin: Should be within the upper rectum to prevent recurrence.
    • Surgical Approaches:
      • Open surgery
      • Laparoscopic or robotic surgery (MIS preferred due to faster recovery).

Special Populations

Right-Sided Diverticulitis

  • Epidemiology:
    • Common in Asian countries; rare in the West.
    • Affects younger patients.
  • Clinical Challenge:
    • Symptoms mimic acute appendicitis.
  • Differential Diagnoses:
    • Meckel's diverticulitis
    • Cholecystitis
    • Ischemic colitis
    • Pelvic inflammatory disease
  • Management:
    • Similar to diverticulitis elsewhere in the colon.
    • Surgery:
      • Right hemicolectomy may be necessary for recurrent or complicated cases.

Immunocompromised Patients

  • Includes:
    • Transplant recipients
    • Patients with diabetes mellitus, renal failure, cirrhosis
    • Patients on systemic steroids or chemotherapy
  • Characteristics:
    • Similar prevalence of diverticulitis as general population.
    • Higher risk of free perforation and complicated disease.
  • Management:
    • Lower threshold for surgery after a single attack.
    • Emergency Surgery:
      • Avoid primary anastomosis due to impaired healing.

Young Patients

  • Previous Beliefs:
    • Thought to have a more aggressive disease course.
    • Recommended surgery after a single episode.
  • Current Evidence:
    • Higher recurrence rates but not higher rates of emergency surgery.
  • Management:
    • No special treatment solely based on age.
    • Follow standard guidelines with individual assessment.

Summary

  • Diverticular disease is common, especially in older adults, and can lead to diverticulitis.
  • Lifestyle modifications can reduce the risk.
  • Diagnosis relies on clinical evaluation and imaging, primarily CT scans.
  • Management depends on the severity:
    • Uncomplicated cases often managed conservatively.
    • Complicated cases may require surgical intervention.
  • Special populations may need tailored management strategies.

Key Takeaways

  • Preventive Measures: High-fiber diet, physical activity, and avoiding red meat and smoking.
  • Clinical Signs: Left lower quadrant pain, fever, and leukocytosis suggest diverticulitis.
  • Imaging: CT scan is essential for diagnosis and staging.
  • Surgical Principles:
    • Remove affected colon segment.
    • Ensure distal margin is within the rectum.
    • Consider minimally invasive techniques.
  • Individualized Care: Treatment decisions should be personalized based on patient factors and disease severity.