Chapter 3-15: Diverticulitis

TEXTBOOK PRESENTATION

Patients typically complain of a constant gradually increasing left lower quadrant abdominal pain, usually present for several days. Diarrhea or constipation and fever are often present. Guarding and rebound may be seen.

DISEASE HIGHLIGHTS

1. Diverticula are outpouchings of the colonic wall that may be asymptomatic (diverticulosis), become inflamed (diverticulitis), or hemorrhage.

2. Diverticulosis

   1. Develops in 5–10% of patients aged > 45 years, 50% in persons aged > 60 years, and 80% in those aged > 85 years.

   2. Low-fiber diets are believed to cause diverticula by decreasing stool bulk, resulting in increased intraluminal pressure causing the mucosa and submucosa to herniate through weakness in the colonic wall created by penetrating vessels.

3. Diverticulitis

   1. Develops secondary to microscopic or frank perforation of diverticula.

   2. 85–95% of diverticulitis occurs in sigmoid or descending colon

   3. Mean age of onset is 63 years.

   4. Complications of diverticulitis

      1. Abscess

      2. Peritonitis

      3. Sepsis

      4. Colonic obstruction

      5. Fistula formation (colovesicular fistula most common)

   5. Simultaneous diverticular hemorrhage and diverticulitis are unusual; diverticular hemorrhage is discussed in Diverticular Bleed.

EVIDENCE-BASED DIAGNOSIS

1. Left lower quadrant tenderness increases the likelihood of diverticulitis; LR+, 3.4; LR–, 0.41.

2. Neither fever nor leukocytosis is very sensitive for diverticulitis or diverticular abscess.

   1. In patients with uncomplicated diverticulitis, only 45% had temperature of ≥ 38.0°C or WBC > 11,000/mcL.

   2. In patients with diverticular abscess, only 64% of patients had temperature of ≥ 38.0°C and 62% had WBC > 11,000/mcL.

3. Plain radiographs may demonstrate free air or obstruction.

4. CT scan

   1. Test of choice in men and nonpregnant women

   2. Can confirm diverticulitis (diverticula with thickened bowel wall or pericolonic fat stranding); evaluate the extent, severity, and complications (abscess formation and perforation); and diagnose other conditions.

   3. 93–97% sensitive

5. Colonoscopy

   1. Colon cancer can be mistaken for diverticulitis on CT.

   2. All patients with diverticulitis should have follow-up colonoscopy (unless one has recently been performed) delayed 4–6 weeks until there is a resolution of acute inflammation.

TREATMENT

1. Outpatient management is appropriate for patients with a mild attack (ie, patients without marked fever or marked leukocytosis, pain manageable with oral analgesics, tolerating oral intake) and without significant comorbidities, immunocompromise, or advanced age.

   1. Antibiotics

      1. Antibiotics have routinely been administered to all patients with diverticulitis.

      2. Recent guidelines have questioned the utility of this approach.

      3. A recent randomized controlled trial of antibiotic therapy in mild diverticulitis proven by CT failed to demonstrate statistically significant improvement with antibiotics over observation.

      4. However, every outcome measured favored antibiotic use over observation; days to recovery 12 versus 14, readmission rate within 6 months 12% vs. 17.6%, total number of readmissions 13.2% vs. 25%, complicated diverticulitis 2.6% vs. 3.8%, ongoing diverticulitis 4.1% vs. 7.3%, sigmoid resection 2.3% vs. 3.8%.

      5. Until further data is available, antibiotic therapy is recommended.

   2. Clear liquid diet

   3. High-fiber diet after attack resolves

   4. Follow-up colonoscopy

2. Moderate to severe attack (unable to tolerate oral intake, more severe pain) necessitates inpatient treatment.

   1. Broad-spectrum antibiotics

   2. No oral intake

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