- Clinical science
Diverticular disease is an umbrella term for a spectrum of intestinal pathologies characterized by abnormal outpouching of the colonic mucosa (diverticula). Diverticulosis refers to the presence of asymptomatic diverticula, while diverticulitis refers to symptomatic diverticular inflammation. The condition is considered a lifestyle disease, seen especially in industrialized nations with low fiber diets and slow fecal transit (e.g., from lack of exercise). Incidence increases with age and more than 50% of individuals are affected by the 7th decade of life. Diverticula are caused by increased intraluminal pressure in the distal colon, resulting in herniation of the inner colonic wall through areas of weakness in the outer muscular layer. This may occur in any part of the colon but is especially common in the sigmoid colon. Most patients are asymptomatic but may present with lower left abdominal pain, change in bowel habits, and fever in the event of diverticulitis. Diagnosis is based on the clinical features and elevation of inflammatory markers in blood tests. Abdominal CT scan is the imaging method of choice and indicated to assess the extent of the disease as well as potential complications. Colonoscopy is contraindicated during acute inflammation but is essential in ruling out malignancy in follow-ups. Uncomplicated diverticulitis may be managed conservatively with antibiotics and bowel rest, while complicated cases may require surgery with colonic resection. Further intervention may be indicated if complications such as diverticular bleeding, perforation, or abscesses arise. Elective surgery is recommended for patients with recurrent diverticulitis or associated conditions such as strictures and fistulae.
- Diverticula: pouches protruding from the colon wall
- Diverticulosis: merely describes the presence of asymptomatic diverticula
Diverticulitis: describes the inflammation of diverticula resulting in clinical symptoms
- Uncomplicated diverticulitis: acute localized inflammation of a colonic diverticulum with no evidence of complications
- Complicated diverticulitis: inflammation of a colonic diverticulum associated with complications, such as, perforation, abscess, fecal peritonitis, bowel obstruction, or fistula formation. 
- Common in Western countries and industrialized societies (∼ 50% of people > 60 years affected)
- Low prevalence in developing countries (estimated as low as < 0.5%)
- In Western societies left-sided diverticulosis, in Asia right-sided more common
Epidemiological data refers to the US, unless otherwise specified.
- Caused mainly by lifestyle and environmental factors
- Increasing age
- Genetic factors
- Diet (low-fiber, rich in fat and red meat)
- Obesity, low physical activity
|I||Diverticulitis with a confined pericolic abscess|
|II||Diverticulitis with distant abscess formation|
|III||Perforated diverticulitis with generalized purulent peritonitis|
|IV||Perforated diverticulitis, free communication with the peritoneum, generalized fecal peritonitis|
- Diverticulitis: stool gets lodged in diverticula → obstruction of intestinal lumen → increased intraluminal pressure and erosion of diverticula wall → inflammation
- Mostly asymptomatic
- Most common cause of lower GI bleeding in adults
- Can present with abdominal pain in patients with chronic constipation
- Low-grade fever
- Sigmoid colon most commonly affected → left lower quadrant pain
- Possibly tender, palpable mass (pericolonic inflammation)
- Change in bowel habits (∼ 50% constipation, 25–35% diarrhea)
- Nausea and vomiting; caused by bowel obstruction or ileus
- ↑ Urinary urgency and frequency (∼ 15%)
- peritonitis → indicates possible perforation and
In elderly or immunocompromised patients clinical symptoms may only be mild!
- Blood tests
- Stool test: rule out pathogens in patients with diarrhea
1st-line: abdominal CT with oral and IV contrast: :
- Diverticula, bowel wall thickening (> 4mm), inflammation of the pericolonic fat with fat stranding (visible traces of fluid in the fat)
- Assessment of complications
- Abscess: fluid collections, surrounding inflammatory changes
- Obstruction: dilated intestinal loops, visualization of air-fluid levels
- Perforation: free air in the abdominal cavity in the event of perforation
- Fistula: air in organs other than the bowel
- Abdominal ultrasound
- Not indicated during an acute episode → ↑ risk of perforation and exacerbating diverticulitis
- Performed once inflammation has subsided (after 6 weeks) to assess extent of diverticulitis and rule out malignancy
- Asymptomatic diverticulosis is often an incidental finding during routine endoscopy
Performing a colonoscopy during the acute phase of diverticulitis should be avoided due to risk of perforation!
- No treatment can reverse the growth of existing diverticula
Prevention of progression
- Regulation of bowel movements
- Increase physical activity
- High-fiber diet
- Plenty of fluids
(Acute) uncomplicated diverticulitis
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(Acute) complicated diverticulitis
- Clear liquid diet
- Consider indications for antibiotics (not routinely indicated) 
- Outpatient treatment with follow up in 2–3 days or earlier if symptoms worsen
- Stabilize the patient.
- Urgent GI and surgery consults
- Broad-spectrum IV antibiotics: See “severe infection” in .
- Manage complications, if present.
- Perforation with fecal peritonitis: See the .
- Bowel obstruction: See the .
- Peridiverticular abscess < 3–4 cm: Continue antibiotics.
- Peridiverticular abscess ≥ 4 cm: ultrasound- or CT-guided percutaneous drainage
- No signs of improvement in 48 hours: Repeat imaging and consider surgical intervention.
- Signs of improvement in 48–72 hours: Start enteral feeds and switch to oral antibiotics.
- Parenteral analgesics
- Parenteral antiemetics
- Inpatient treatment
- Serial abdominal examination
- Frequency: occurs in around 5% of cases of patients with diverticulosis
- Caused by erosions around the edge of diverticula
- Clinical findings
- Differential diagnosis: other causes of (e.g., hemorrhoidal bleeding)
- Perforation: symptoms of caused by
- Colovesical (most common)
- Other forms: colovaginal, coloenteric, colocutaneous
- Intestinal obstruction
We list the most important complications. The selection is not exhaustive.