Predisposing Factors

• Right-sided diverticula is predominant in Asian populations, while left-sided disease is more common in Western populations
• A diet that is low in fiber & high in fat & red meat
• Incidence increases with age
  • The disease is rare in individuals <40 years old

• Disease frequency is similar in both genders
• Other factors which may predispose to diverticulitis are colonic motility disorders, colonic wall defects, ingestion of nonsteroidal anti-inflammatory drugs (NSAIDs) & ingestion of corticosteroids

• A thorough clinical history must be obtained to help rule out other causes of abdominal pain

• A complete directed physical exam must be conducted including abdominal, rectal & pelvic exams
• Abdominal findings:
  • Direct & rebound tenderness over the involved area is noted in cases of localized peritonitis
  • Generalized tenderness, involuntary guarding & decreased or absent bowel sounds are seen in generalized peritonitis
  • A mass is occasionally palpated at the site of inflammation & may be apparent on abdominal palpation, rectal or pelvic exam
  • Abdomen may be distended & tympanic on percussion

• A rectal exam may help elicit tenderness, establish stool color & check for gastrointestinal bleeding

• Complete blood count (CBC)
  • Leukocytosis with or without a left shift indicates infection
  • Immunocompromised & elderly patients may have normal results

• Liver function tests (LFTs), lipase, amylase
  • May help establish other causes of abdominal pain

• Blood cultures
  • Perform prior to giving empiric antibiotic therapy

• Urinalysis & urine cultures
  • Demonstrate urinary tract infection (UTI), which is most likely due to a colovesicular fistula

If the clinical picture is clear, some experts suggest that a diagnosis of diverticulitis can be made on the basis of clinical criteria alone

Abdominal Computed Tomography (CT) Scan

• There is an increasing trend toward using the CT scan as the imaging test of choice for the evaluation of acute diverticulitis
  • Sensitivity is reported at 79-99% with specificity at 72%

• Criteria for diagnosis of diverticulitis include the following:
  • Colonic wall thickening
  • Pericolic fat infiltration
  • Pericolic or distant abscesses
  • Extraluminal air

• Able to determine disease extent ie presence of abscesses, thus facilitating the decision of administering medical vs surgical therapy
• May be employed in performing percutaneous drainage of abscesses
• Able to show extracolonic diseases which may present with symptoms similar to those of diverticulitis eg tubo-ovarian abscess, aortic leakage
• Not useful in differentiating cancer from diverticulitis

• Able to detect abscesses & other colonic diseases eg ischemic colitis, inflammatory bowel disease (IBD) that may present in a similar manner
  • Not an imaging test of choice during an acute episode of abdominal pain

• May underestimate the severity of the disease because it cannot demonstrate the extramural nature of diverticulitis
• Cost of the test is low & test is available in most centers
• Use of water-soluble contrast media is advisable
  • Barium contrast is generally not recommended because of the risk of colonic perforation & subsequent peritonitis

• Criteria for diagnosis of diverticulitis include the following:
  • Presence of diverticula, intramural mass, mass effect or sinus tract
  • Extravasation of contrast suggests perforation

Transabdominal Ultrasound

• Safe noninvasive test but is examiner-dependent
• Criteria for the diagnosis of diverticulitis include wall thickening, abscess & rigid hyperechogenicity of the colon
• The test is valuable in women of childbearing age who present with left lower abdominal quadrant pain & fever
  • More sensitive than computed tomography (CT) or contrast enema in detecting gynecologic abnormalities eg ectopic pregnancy & pelvic inflammatory disease (PID)

Abdominal X-ray

• Provides limited information except in cases where perforation or obstruction are suspected
• Plain & upright films may show ileus, free air (pneumoperitoneum) or obstruction

The management of diverticulitis depends on the clinical presentation, severity of inflammation, location of the lesion & presence of concomitant diseases

Uncomplicated Diverticulitis

• Refers to diverticulitis without associated abscess, obstruction, fistula, perforation, or peritonitis

Complicated Diverticulitis

• Refers to diverticulitis with complications including abscess, obstruction, fistula, perforation, stricture, or peritonitis
• Divided into stages by the Hinchey classification