Diverticular disease and diverticulitis

Introduction

Diverticular disease refers to the spectrum of clinical manifestations arising from the presence of diverticula—sac-like protrusions of the mucosa and submucosa through weak points in the muscular wall of the colon. These diverticula are most common in the sigmoid colon but can occur throughout the large intestine.

• Diverticulosis: Presence of colonic diverticula without symptoms.

• Diverticular disease: Diverticulosis with clinical symptoms (e.g., abdominal pain, bloating, changes in bowel habits).

• Diverticulitis: Inflammation or infection of one or more diverticula, leading to acute clinical manifestations.

Diverticular disease is one of the most common gastrointestinal conditions in Western populations and represents a significant cause of outpatient visits, hospital admissions, and healthcare expenditures.

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Epidemiology

• Prevalence increases with age:

  • <10% at age 40.

  • 50–60% at age 60.

  • 70% at age 80.

• More common in Western countries (associated with low-fiber diets).

• In Asia and Africa, diverticula are less frequent and tend to occur in the right colon.

• Complications (diverticulitis, bleeding) occur in 10–25% of patients with diverticulosis.

• Diverticulitis is the leading indication for elective colon resection in the United States.

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Pathophysiology

Diverticula form at points where vasa recta penetrate the circular muscle of the colon wall, creating structural weakness.

Contributing Factors

1. Dietary factors – Low fiber intake → harder stools → increased intraluminal pressure.

2. Aging – Loss of connective tissue strength and colonic wall elasticity.

3. Motility abnormalities – High-pressure contractions in sigmoid colon.

4. Microbiome alterations – Dysbiosis may contribute to inflammation.

5. Obesity and lifestyle – Physical inactivity, smoking, and NSAID use increase risk.

Pathogenesis of Diverticulitis

• Fecalith or food particle obstructs diverticular neck.

• Bacterial overgrowth and mucosal damage occur.

• Local inflammation progresses to microperforation.

• Can evolve into abscess, fistula, obstruction, or generalized peritonitis if untreated.

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Clinical Features

1. Diverticulosis

• Usually asymptomatic.

• May cause nonspecific symptoms: bloating, constipation, left lower quadrant discomfort.

2. Symptomatic Diverticular Disease

• Intermittent abdominal pain, often in the left lower quadrant (LLQ).

• Relief after defecation or passage of flatus.

• Changes in bowel habits: constipation or diarrhea.

3. Acute Diverticulitis

• LLQ pain and tenderness.

• Fever, leukocytosis.

• Anorexia, nausea, vomiting.

• Altered bowel habits (usually constipation, sometimes diarrhea).

4. Complicated Diverticulitis

• Abscess (pericolic, pelvic).

• Perforation with peritonitis.

• Fistula formation (colovesical, colovaginal).

• Obstruction due to chronic inflammation and scarring.

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Diagnosis

1. Laboratory Investigations

• CBC: Leukocytosis in acute diverticulitis.

• CRP: Elevated in acute inflammation.

• Blood cultures: If systemic infection suspected.

2. Imaging

• CT scan (contrast-enhanced) – gold standard. Findings:

  • Bowel wall thickening (>4 mm).

  • Pericolic fat stranding.

  • Presence of abscess or perforation.

• Ultrasound: Useful alternative, particularly in younger or pregnant patients.

• Plain abdominal X-ray: May show ileus or free air in perforation.

3. Endoscopy

• Colonoscopy is contraindicated in acute diverticulitis (risk of perforation).

• Performed after resolution (6–8 weeks later) to exclude colorectal cancer.

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Management

1. Uncomplicated Diverticulosis

• High-fiber diet (25–30 g/day).

• Adequate hydration.

• Lifestyle modification: exercise, weight management, smoking cessation.

• Avoid excessive NSAID use.

2. Symptomatic Diverticular Disease

• Dietary fiber supplementation (psyllium, methylcellulose).

• Antispasmodics (e.g., hyoscine butylbromide 10–20 mg orally up to 3 times daily) for cramp relief.

• Rifaximin (non-absorbable antibiotic) has been used intermittently (400 mg twice daily for 7 days each month) in Europe for symptom control.

3. Acute Uncomplicated Diverticulitis

a) Supportive Measures

• Bowel rest (clear liquid diet progressing as tolerated).

• Analgesia:

  • Paracetamol (acetaminophen): 500–1000 mg every 6 hours.

  • Avoid NSAIDs if possible due to risk of bleeding and perforation.

• Antiemetics as needed.

b) Antibiotic Therapy

Use is selective (not always required in mild cases), but indicated in moderate to severe cases or in immunocompromised patients.

First-line regimens (outpatient):

• Amoxicillin-clavulanate: 875/125 mg orally twice daily for 7–10 days.

• Ciprofloxacin + Metronidazole:

  • Ciprofloxacin 500 mg orally twice daily + Metronidazole 500 mg orally three times daily for 7–10 days.

Inpatient regimens (IV):

• Ceftriaxone + Metronidazole:

  • Ceftriaxone 1–2 g IV once daily + Metronidazole 500 mg IV every 8 hours.

• Piperacillin–tazobactam: 3.375–4.5 g IV every 6–8 hours.

• Meropenem: 1 g IV every 8 hours (reserved for resistant/critically ill cases).

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4. Complicated Diverticulitis

• Abscess <3 cm: Treated with IV antibiotics alone.

• Abscess ≥3 cm: Percutaneous drainage + IV antibiotics.

• Generalized peritonitis/perforation: Emergency surgery (Hartmann’s procedure or primary resection with anastomosis).

• Fistulae/obstruction: Elective surgical resection after stabilization.

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5. Chronic/Recurrent Diverticulitis

• Patients with recurrent attacks or complications may require elective sigmoid colectomy.

• Surgery reduces recurrence but does not completely eliminate risk.

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Long-term Management and Prevention

• High-fiber diet and supplementation.

• Regular physical activity.

• Weight management.

• Probiotics and cyclic antibiotics (rifaximin) under specialist guidance.

• Colonoscopy surveillance if indicated.

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Prognosis

• Majority of patients with diverticulosis remain asymptomatic.

• 20–25% develop diverticulitis over time.

• Among acute diverticulitis cases:

  • 75% uncomplicated.

  • 25% complicated (abscess, perforation, fistula, obstruction).

• Mortality is low in uncomplicated cases (<1%) but high in perforated diverticulitis with peritonitis (up to 20%).

• Recurrence risk: 15–30% after an initial episode.

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Future Directions

• Research into the role of gut microbiota modulation (via probiotics or antibiotics).

• Personalized prevention based on genetic susceptibility.

• Minimally invasive surgical techniques with better outcomes.

• Improved biomarkers for early detection of complicated diverticulitis.