Diagnosing Diverticulitis

Clinical Presentation and Initial Assessment

The American Gastroenterological Association suggests that the most common presenting symptom of diverticulitis is abdominal pain, usually acute or subacute in onset and located in the left lower quadrant 4, 5
The American Gastroenterological Association recommends that other presenting signs and symptoms of diverticulitis include fever 6, change in bowel habits 4, 5, nausea without vomiting 4, 5, and elevated white blood cell count and/or C-reactive protein (CRP) [4, 5] [4, 5]
Clinical diagnosis alone is correct in only 40-65% of patients, highlighting the need for imaging in many cases, according to the American Gastroenterological Association 4, 5

The American College of Radiology states that CT scan of the abdomen and pelvis with oral and intravenous contrast is highly accurate for diagnosing diverticulitis with sensitivity/specificity of 95% 4, 5
The American College of Radiology recommends CT imaging when patient has no prior imaging-confirmed diagnosis of diverticulitis 1, 2, 3, 4, severe presentation suggesting complications 4, 7, failure to improve with therapy 4, 5, patient is immunocompromised 4, 5, multiple recurrences, especially if contemplating prophylactic surgery 4, 5, symptom duration before clinical presentation longer than 5 days 1, 7, or signs of perforation, bleeding, obstruction, or abscess [1, 3, 7] [1, 2, 3, 4]
Alternative imaging options when CT cannot be obtained include abdominal ultrasonography and abdominal MRI, as suggested by the American College of Radiology 1, 4

The American College of Radiology notes that colorectal cancer can mimic both clinical and radiographic findings of diverticulitis 8, 9
The American College of Radiology states that CT findings suggesting colon cancer rather than diverticulitis include pericolonic lymphadenopathy (>1 cm in short axis) with or without pericolonic edema 8, 9
The American College of Radiology recommends that CT findings suggesting diverticulitis include inflammatory changes 4, edema in the root of the sigmoid mesentery 9, and no pericolonic lymphadenopathy adjacent to a segment of thickened colon wall 8, 9

The American Gastroenterological Association advises that colonoscopy is recommended after an episode of complicated diverticulitis and after a first episode of uncomplicated diverticulitis 4, 5
The American Gastroenterological Association suggests that colonoscopy may be deferred if a recent (within 1 year) high-quality colonoscopy was performed 4, 5
The American Gastroenterological Association recommends that colonoscopy should be delayed by 6-8 weeks or until complete resolution of the acute symptoms, whichever is longer 4, 5
The American Gastroenterological Association notes that the risk of colon cancer is higher in patients with complicated diverticulitis (7.9%) compared with patients with uncomplicated diverticulitis (1.3%) 4, 6