Acute Diverticulitis – Expanding Utility of Abdominal Ultrasound

June 28, 2021

Written by Drew Clare, SAEM AEUS

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In patients with suspected uncomplicated acute diverticulitis, consider ultrasound as a first approach.

Why does this matter?
Acute diverticulitis recurs in up to 22% of patients. This paper highlights an opportunity to avoid accumulating radiation doses in the patients who present to the Emergency Department with recurrent left lower quadrant pain for the third time this year.

Don’t be tempted to click “CT scan entire body” for your next patient with LLQ pain. 
As time goes on, Emergency Physicians are getting more comfortable with the utilization of POCUS in the diagnosis of abdominal pain.  This is becoming particularly important to those that work in hospitals where the CT scanners never seem to be working (or properly staffed).  This review article has a series of cases that suggest it might be time to start treating diverticulitis like ureteral colic; avoid reflexively clicking “CT scan entire body,” and get that ultrasound out.

The scanning protocol: begin scanning with a linear probe or an abdominal probe (on patients with a generous body habitus) to evaluate the sigmoid colon. Starting with the lower end of the probe over the left anterior superior iliac spine, scan in a circular motion evaluating the colon as it descends toward the midline attempting to visualize the distal portion of the sigmoid behind the bladder.  Typical diverticulitis looks like a small sac-like outpouching of bowel with a peripheral hypoechoic ring and central echogenicity (the pseudokidney sign, see figure below).  The sensitivity and specificity have been reported to be as high as 94% and 99% respectively.

It is important to note the target population of “mild diverticulitis” is a patient with LLQ pain, normal vital signs, no significant lab abnormalities and no peritoneal signs. POCUS for left lower quadrant pain is not perfect, and this protocol should not be applied to patients that are acutely ill or immunosuppressed.  When looking for acute diverticulitis you could miss important alternate etiologies such as epiploic appendagitis, malignancy, or other rare abdominal disorders; therefore, this may limit its utility to those with a previous history of acute diverticulitis.

Source
Utility of point-of-care ultrasound in patients with suspected diverticulitis in the emergency department. J Clin Ultrasound. 2020 Jul;48(6):337-342. doi: 10.1002/jcu.22857. Epub 2020 May 1.