Colonic Diverticula

Definition, Etiology, PathogenesisTop

Acquired colonic diverticula are small (usually 5-10 mm in diameter) hernias of the mucosa and submucosa through the muscular layer of the colon (pseudo-diverticula). They occur in ≥50% of people aged >60 years, most often in the sigmoid colon (>90%), less frequently in the proximal parts of the colon, never in the rectum.

Congenital diverticula are protrusions of all layers of the intestinal wall, usually single in the cecum. They occur rarely and have little clinical significance.

Risk factors for acquired diverticula include long-term smoking, adiposity, low dietary fiber or high dietary red meat intake, consumption of caffeine and alcohol, lack of physical activity, and possibly type 2 diabetes.

Clinical FeaturesTop

In most cases (up to 80%), there are no symptoms and diverticula are detected incidentally during diagnostic tests performed for a different indication. This asymptomatic clinical form of the disease is called colonic diverticulosis. In the symptomatic form (diverticular disease of the colon), pain in the lower left abdominal quadrant and an altered bowel habit are common.

DiagnosisTop

Diagnostic Tests

Diverticula are most often detected during colonoscopy performed for different indications. They are also visualized by barium enema (currently rarely performed). Both tests are contraindicated in acute diverticulitis (see below).

Computed tomography (CT) of the abdomen and pelvis is the most useful test for diagnosis of diverticulitis, which manifests as thickening of the colon wall and inflammatory infiltration of adipose tissue, and its complications (abscess, perforation, obstruction). Abdominal ultrasonography can also be used to detect both diverticula and abscesses.

Differential Diagnosis

Irritable bowel syndrome, colorectal cancer, Crohn disease, ischemic colitis, infectious enteritis, some gynecological diseases (ovarian cancer, pelvic inflammatory disease), cystitis.

TreatmentTop

1. Asymptomatic diverticulosis does not require treatment. A gradual increase in the consumption of soluble fiber is advised to achieve softer stool consistency and increased stool bulk. Contrary to previous suggestions, there are no contraindications to eating seeds or nuts.

2. Abdominal discomfort associated with diverticulosis can be managed with antispasmodics, anticholinergics, and acetaminophen, but their relative effectiveness has not been tested in clinical trials. Nonsteroidal anti-inflammatory drugs (NSAIDs) and opioids should be avoided.

3. The NICE guidelines advise informing patients about the potential benefits of exercise, weight loss (in the case of overweight or obesity), and smoking cessation in reducing the risk of developing symptomatic disease and its complications (acute diverticulitis).

ComplicationsTop

1. Acute diverticulitis affects ~5% of patients with diverticulosis. Inflammation begins in a single diverticulum and can progress to development of an abscess, accompanied by pain and fever. Microperforation and free perforation can occur, with findings of local or more extensive peritonitis. Patients with mild symptoms and without peritonitis can be treated with analgesics on an outpatient basis. For immunocompetent patients without serious comorbidities, antibiotics may not be necessary. Antibiotic therapy is indicated for complicated diverticulitis (defined as presence of perforation, abscess, fistula, or obstruction), as well as for uncomplicated diverticulitis with one of the following: immunosuppression, concomitant serious disease, vomiting, persistence of symptoms >5 days, baseline serum C-reactive protein (CRP) >140 mg/L, or leukocyte count >15×109/L. All patients require reassessment 2 to 3 days after starting treatment. Our usual pattern of practice is then to see them biweekly until symptoms resolve. Hospitalization is indicated for severe or complicated inflammation, in elderly patients with comorbidities, and i pregnant women. Hospital treatment involves diet restriction, hydration, parenteral analgesics, and parenteral antibiotics. Appropriate antibiotic regimens, such as amoxicillin with clavulanic acid or ciprofloxacin with metronidazole, would offer gram-negative and anaerobic bacteria coverage. After resolution of complicated diverticulitis and after the first episode of uncomplicated diverticulitis, colonoscopy is advised, if not performed in the last year (usually at least 6-8 weeks after resolution of acute illness; possibly earlier if alarming symptoms are present). A high-quality diet, physical activity, smoking cessation, and avoidance of NSAIDs other than acetylsalicylic acid (ASA) are recommended after acute uncomplicated or complicated diverticulitis. There are no restrictions on intake of nuts or seeds. Use of probiotics, antibiotics, or aminosalicylates is not recommended for secondary prevention. Elective segmental colectomy can be considered in patients with recurrent diverticulitis; however, the decision to proceed is based on disease severity, surgical risk, and patient preference rather than the number of episodes.

2. Perforation and obstruction complicating acute diverticulitis require urgent surgical intervention. This is most often a Hartmann procedure with subsequent restoration of bowel continuity.

3. Fistulas occur most often between the sigmoid colon and bladder (with recurrent urinary tract infection, pyuria, or pneumaturia), vagina (with leakage of air or feces from the vagina), or small intestine (with diarrhea and abdominal pain). Diagnosis is based on CT or magnetic resonance imaging (MRI), with the investigation site determined by location (eg, cystoscopy, gynecological examination). Colonoscopy should be performed to exclude colorectal cancer. Usually elective surgery is necessary.

4. Intra-abdominal abscesses are managed according to the location and size of the abscess and the general condition of the patient. Abscesses <3 cm adjacent to the intestinal wall in patients in good general condition can initially be treated medically. Larger abscesses or abscesses not associated with the intestinal wall should be treated with radiologic or surgical drainage, resection, or both.

5. Diverticular hemorrhage stops spontaneously in 80% of cases but can be life-threatening. Hemostasis can be attempted by endoscopic methods (cautery, injection, or clips) or by interventional radiology. Persistent or recurrent bleeding may require surgical intervention.