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Clinical Subject Page

Diverticulosis

Diverticulosis is the presence of small sac-like pouches called diverticula in the wall of the colon, most commonly in the sigmoid colon. Most patients have no symptoms, and the condition is often discovered incidentally during colonoscopy or abdominal imaging

Also called

Colonic diverticulosis

ICD-10

K57.30

Specialty

Gastroenterology

Onset

Chronic

Reviewed

July 2026

On This Page

Overview

Diverticulosis develops when the inner lining of the colon protrudes through weak areas in the muscular bowel wall. It becomes more common with increasing age and usually causes no symptoms. Some patients develop abdominal discomfort, bloating, constipation, diarrhea, or painless lower gastrointestinal bleeding. Diverticulosis may later become complicated by diverticulitis, diverticular bleeding, fistula, obstruction, or perforation.

Etiology & Risk Factors

Aetiology

The exact cause is multifactorial. Diverticula form when increased pressure inside the colon pushes the mucosa and submucosa through weak points in the muscular wall, usually where blood vessels enter the colon.

Risk Factors

  • Increasing age

  • Low dietary fiber intake

  • Chronic constipation

  • Obesity

  • Physical inactivity

  • Smoking

  • Diet high in red and processed meat

  • NSAID use

  • Corticosteroid use

  • Opioid use

  • Family history of diverticular disease

  • Connective tissue disorders

Pathophysiology

Repeated increased intraluminal pressure within the colon causes the mucosa and submucosa to herniate through weak points in the muscular bowel wall. This produces false diverticula, usually along the sigmoid colon. Most remain asymptomatic, but injury to nearby blood vessels may cause bleeding, while obstruction and microperforation of a diverticulum may lead to diverticulitis.

Clinical Presentation

  • Most Patients

    • Asymptomatic

    • Discovered incidentally during colonoscopy or imaging

    Possible Symptoms

    • Intermittent lower abdominal discomfort

    • Abdominal bloating

    • Constipation

    • Diarrhea

    • Altered bowel habits

    • Painless rectal bleeding

    Diverticular Bleeding

    • Sudden painless passage of bright-red or maroon blood

    • May be mild or significant

    • Usually stops spontaneously but may recur

History Taking

Ask about:

    • Abdominal discomfort or bloating
    • Constipation or diarrhea
    • Changes in bowel habits
    • Rectal bleeding
    • Stool color and amount of blood
    • Previous diverticulitis
    • Previous colonoscopy
    • Dietary fiber intake
    • NSAID or anticoagulant use
    • Family history of colorectal disease

Physical Examination

General Examination

Look for:

  • Pallor

  • Tachycardia

  • Hypotension if significant bleeding

  • Signs of dehydration

Abdominal Examination

Assess for:

  • Abdominal tenderness

  • Distension

  • Palpable masses

  • Bowel sounds

  • Guarding or rebound tenderness

Uncomplicated diverticulosis usually produces a normal abdominal examination.

Rectal Examination

Assess for:

  • Fresh or altered blood

  • Anorectal causes of bleeding

  • Rectal mass

Investigations

Asymptomatic Diverticulosis

No specific investigation is required if diverticulosis is found incidentally and the patient has no concerning symptoms.

Laboratory Tests

When symptoms or bleeding are present:

  • Complete blood count

  • Iron studies

  • Renal function and electrolytes

  • Coagulation profile

  • C-reactive protein if inflammation is suspected

  • Blood group and crossmatch for significant bleeding

Colonoscopy

May identify:

  • Number and location of diverticula

  • Active or recent bleeding

  • Polyps or colorectal cancer

  • Alternative causes of symptoms

Colonoscopy is often how incidental diverticulosis is detected.

CT Abdomen and Pelvis

May be used when:

  • Diverticulitis is suspected

  • Abdominal pain is significant

  • Complications are suspected

  • Another diagnosis needs to be excluded

Investigation of Active Bleeding

Depending on severity:

    • Urgent colonoscopy

    • CT angiography

    • Catheter angiography

Diagnosis

Diagnosis is usually made by identifying colonic diverticula during:

    • Colonoscopy
    • CT imaging
    • CT colonography
    • Contrast imaging performed for another indication

Management

Asymptomatic Diverticulosis

  • Reassurance

  • No antibiotics

  • No surgery

  • Encourage a balanced, fiber-rich diet

  • Maintain adequate hydration

  • Regular physical activity

  • Maintain a healthy body weight

  • Avoid smoking

A diet rich in fiber, fruit, and vegetables is generally advised for patients with diverticulosis.

Symptomatic Uncomplicated Diverticular Disease

Management may include:

  • Gradual increase in dietary fiber

  • Fiber supplements when dietary intake is insufficient

  • Adequate fluid intake

  • Simple analgesia

  • Management of constipation

  • Assessment for other causes of chronic symptoms

Diverticular Bleeding

    • Assess hemodynamic stability

    • Establish intravenous access

    • Check hemoglobin and crossmatch blood

    • Stop or reverse anticoagulation when clinically appropriate

    • Colonoscopy for diagnosis and endoscopic treatment

    • CT angiography or angiographic embolization for ongoing major bleeding

    • Surgery only for uncontrolled or recurrent severe bleeding

Complications

  • Acute diverticulitis
  • Diverticular bleeding
  • Colonic abscess
  • Perforation
  • Fistula
  • Colonic stricture
  • Bowel obstruction
  • Recurrent diverticular disease

Prognosis

  • Most patients with diverticulosis remain asymptomatic and never develop serious complications. Some may experience recurrent abdominal symptoms, diverticulitis, or diverticular bleeding. Prognosis is generally good with appropriate lifestyle measures and timely treatment of complications

Key Points / Clinical Pearls

  • Diverticulosis is the presence of diverticula without inflammation.
  • It most commonly affects the sigmoid colon.
  • Most patients are asymptomatic.
  • The condition is often found incidentally during colonoscopy or CT.
  • Diverticular bleeding is typically painless.
  • Fever and localized tenderness suggest diverticulitis.
  • Management mainly involves a healthy, fiber-rich diet and treatment of symptoms.
  • Antibiotics are not used for uncomplicated diverticulosis.
  • Nuts and seeds do not need to be routinely avoided.
  • Persistent bleeding or altered bowel habits should be evaluated for other conditions, including colorectal cancer.