What are the causes, risk factors, preventive measures, signs, symptoms, and treatment options for Diverticulitis (inflammation of the diverticula)?

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Last updated: February 20, 2025View editorial policy

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From the Guidelines

Diverticulitis is an inflammation of small pouches (diverticula) that form in the digestive tract, typically in the colon, and its management involves a comprehensive approach to prevent complications and recurrence.

Cause and Risk Factors

Diverticulitis occurs when diverticula become inflamed or infected, often due to fecal matter getting trapped in these pouches. The risk factors for diverticulitis include:

  • Age (more common in people over 40)
  • Low-fiber diet
  • Obesity
  • Lack of exercise
  • Smoking
  • Certain medications (e.g., NSAIDs)
  • Genetic factors, with approximately 50% of the risk attributable to genetic factors 1

Preventive Measures

To reduce the risk of developing diverticulitis, the following preventive measures are recommended:

  1. Eat a high-fiber diet (25-30g daily)
  2. Stay hydrated
  3. Exercise regularly
  4. Maintain a healthy weight
  5. Quit smoking

Signs and Symptoms

The signs and symptoms of diverticulitis include:

  • Abdominal pain, usually on the lower left side
  • Fever
  • Nausea and vomiting
  • Constipation or diarrhea
  • Bloating
  • Rectal bleeding (in severe cases)

Treatment

The treatment of diverticulitis depends on the severity of the condition. For mild cases, the following approach is recommended:

  • Rest and clear liquid diet for a few days
  • Antibiotic treatment can be used selectively, rather than routinely, in immunocompetent patients with mild uncomplicated diverticulitis 1
  • Oral antibiotics (e.g., ciprofloxacin 500mg twice daily + metronidazole 500mg three times daily for 7-10 days) may be prescribed for patients with uncomplicated diverticulitis who have comorbidities or are frail, who present with refractory symptoms or vomiting, or who have a CRP >140 mg/L or baseline white blood cell count > 15 × 10^9 cells per liter 1
  • Gradually reintroduce low-fiber foods, then transition to a high-fiber diet For severe cases, hospitalization, intravenous antibiotics, bowel rest, and possible surgical intervention for complications like perforation or abscess may be necessary.

Management and Follow-up

After recovery, it is essential to maintain a high-fiber diet and healthy lifestyle to prevent recurrence. Patients should consult a doctor immediately if symptoms worsen or persist, as complications can be serious. The American College of Physicians (ACP) suggests that clinicians use abdominal CT imaging when there is diagnostic uncertainty in a patient with suspected acute left-sided colonic diverticulitis (conditional recommendation; low-certainty evidence) 1. Additionally, the ACP recommends managing most patients with acute uncomplicated left-sided colonic diverticulitis in an outpatient setting (conditional recommendation; low-certainty evidence) and initially managing select patients with acute uncomplicated left-sided colonic diverticulitis without antibiotics (conditional recommendation; low-certainty evidence) 1.

From the Research

Causes and Risk Factors

  • Diverticulitis is characterized by inflammation of the outpouchings of the bowel wall 2
  • The exact mechanism that leads to diverticulitis from diverticulosis is not definitively known 3
  • Risk factors for the development of diverticulitis include:
    • Obesity
    • Smoking
    • Nonsteroidal anti-inflammatory drugs
    • Corticosteroids
    • Opiates 4
    • Age, with the prevalence increasing with age 5
    • Diet, with a high fiber diet potentially decreasing the likelihood of symptomatic diverticulitis 3
    • Genetic factors, with a familial association and a specific gene, TNFSF 15, potentially predicting severity of disease 6

Preventive Measures

  • A high fiber diet may help prevent future attacks of diverticulitis 3, 4
  • Increasing fiber intake may help prevent future episodes of diverticulitis 4
  • Prophylaxis with probiotics, laxatives, anti-spasmotics, anticholinergic drugs, and salicylates are being studied as potential preventive measures 5
  • A healthy lifestyle and avoidance of smoking may also help prevent diverticulitis 5

Signs and Symptoms

  • The most common presenting complaint is left lower quadrant abdominal pain with symptoms of systemic unwellness, including fever and malaise 3
  • Symptoms may vary widely, and the presentation may be atypical 3
  • Diverticulitis can be asymptomatic, or patients may experience nonspecific abdominal pain, isolated or recurrent 4

Treatment Options

  • Uncomplicated acute diverticulitis may be safely managed as an out-patient in carefully selected patients 3
  • Hospitalization is usually necessary for patients with immunosuppression, intolerance to oral intake, signs of severe sepsis, lack of social support, and increased comorbidities 3
  • The role of antibiotics has been questioned, and it is likely that we will see more patients with uncomplicated disease treated with observation in the future 3
  • Surgical intervention may be necessary for complicated diverticulitis, and the decision to proceed with surgery should be made on an individualized basis 3
  • Elective surgery may be indicated in some cases, but the indications have changed over the past decades, and it may not suggest a reduction in morbidity and mortality 5

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Diverticulitis: An Update From the Age Old Paradigm.

Current problems in surgery, 2020

Research

Diverticulosis and Diverticulitis.

Mayo Clinic proceedings, 2016

Research

Pathogenesis of diverticulosis and diverticular disease.

Minerva gastroenterologica e dietologica, 2017

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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