Diverticulitis Diagnosis

• 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 and pelvic exams
• Abdominal findings:
  • Abdomen may be distended and tympanic on percussion 
  • Generalized tenderness, involuntary guarding and decreased or absent bowel sounds are seen in generalized peritonitis
  • Direct and rebound tenderness over the involved area is noted in cases of localized peritonitis
  • A mass is occasionally palpated at the site of inflammation and may be apparent on abdominal palpation, rectal or pelvic exam
• A rectal exam may help elicit tenderness, establish stool color and check for gastrointestinal bleeding

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

• Selective imaging is recommended in patients with a previous history of acute diverticulitis, absence of vomiting, pain localized to the left lower quadrant and/or a C-reactive protein (CRP) level of >50 mg/L 

Abdominal Computed Tomography (CT) Scan 

• The imaging test of choice for the evaluation of acute diverticulitis
  • Sensitivity is reported at 95% with specificity at 96%
• Able to determine disease extent ie presence of abscesses, thus facilitating the decision of administering medical versus 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
• Criteria for diagnosis of diverticulitis include the following:
  • Colonic wall thickening
  • Pericolic fat infiltration
  • Pericolic or distant abscesses
  • Extraluminal air
  • Presence of intra-abdominal free fluid
• Not useful in differentiating cancer from diverticulitis

Contrast Enema  

• Able to detect abscesses and 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 and 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 and 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
  • Avoids radiation but less accurate in detecting abscess
• An alternative to CT scan when it is not available or is contraindicated 
• The test is valuable in women of childbearing age who present with left lower abdominal quadrant pain and fever
  • More sensitive than CT or contrast enema in detecting gynecologic abnormalities eg ectopic pregnancy and pelvic inflammatory disease (PID)
• Criteria for the diagnosis of diverticulitis include wall thickening, abscess and rigid hyperechogenicity of the colon 

Magnetic Resonance Imaging (MRI)

• Has high sensitivity and specificity but time-consuming 
• An alternative to CT scan when it is not available or is contraindicated 
• May be used when ultrasound is found to be inconclusive in pregnant women
• May be more useful than CT in differentiating carcinoma from diverticulitis
  

Abdominal X-ray  

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

Complete Blood Count (CBC)

• Leukocytosis with or without a left shift indicates infection
• Immunocompromised and elderly patients may have normal results

Liver Function Tests (LFTs), Lipase, Amylase

• May help establish other causes of abdominal pain

C-reactive Protein (CRP)

• Correlates with disease severity and recurrence

Blood Cultures

• Perform prior to giving empiric antibiotic therapy

Urinalysis and Urine Cultures

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

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

Uncomplicated Diverticulitis

Acute Uncomplicated Diverticulitis 

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

Chronic Uncomplicated Diverticulitis 

• Refers to an incomplete resolution of an acute diverticulitis with absence of luminal stenosis

Complicated Diverticulitis

• Findings suggestive of complicated diverticulitis:
  • Severe, generalized abdominal pain with abdominal rigidity and guarding may be due to peritonitis
  • Abdominal mass on palpation or peri-rectal fullness on rectal exam with intra-abdominal abscess
  • Abdominal distention with colicky pain, constipation or vomiting in cases of intestinal obstruction
  • Purulent or fecaloid vaginal discharge in patients with colovaginal fistulas
  • Fecaluria or pneumaturia in patients with colovesicular fistulas
  • Back or lower extremity pain in cases of retroperitoneal gut perforation

Acute Complicated Diverticulitis

• Refers to diverticulitis with complications including abscess, obstruction, fistula, perforation, stricture, or peritonitis
• Divided into stages by the Hinchey classification
  • Hinchey I: Pericolic abscess
  • Hinchey II: Intra-abdominal/retroperitoneal/pelvic abscess
  • Hinchey III: Purulent peritonitis
  • Hinchey IV: Fecal peritonitis

 Chronic Complicated Diverticulitis

• Includes stenotic disease that can lead to fistula formation and acute bowel obstruction