Ultrasound accurately diagnoses midgut volvulus

July 8, 2020

A retrospective study examines whether limited abdominal ultrasound is a safe and e­ffective way to assess for intestinal malrotation with or without midgut volvulus.

A limited abdominal ultrasound (US) is a safe and e­ffective way to assess for intestinal malrotation (IM) with or without midgut volvulus (MGV), according to a retrospective study. An upper gastrointestinal (UGI) series has long been considered the imaging gold standard for making this assessment.

Investigators searched radiology reports at a children’s hospital for patients who were evaluated for MGV using US during 2016 and 2017 and examined the relevant charts for any events that happened in the month following the US. Of the 195 patients who received a US evaluation, the most common presentations were vomiting (44%) followed by abdominal pain and suspected malrotation. Median age was 77 days, with 91% of patients aged younger than 1 year, half of whom were aged younger than 1 month.

The US studies were evaluated for 2 abnormalities: twisting of the small bowel and vasculature around the superior mesenteric artery (SMA), indicative of IM; and occlusion of the SMA, indicating MGV. Of the 195 US studies, 179 were diagnostic; that is, they could include or exclude MGV. (Sixteen studies were not diagnostic because of overlying bowel gas.) Of the diagnostic studies, 14 were found to be positive for MGV, which was confirmed at surgery. For the 164 patients with a negative US who did not have surgery, no negative outcomes were reported. In other words, US was diagnostic in 92% of patients, and in those individuals, it had a sensitivity and specificity of 100%.

Seven of the 16 patients with nondiagnostic US studies were evaluated further with UGI exams, and all tested negative for MGV or malrotation, although 1 patient later was confirmed surgically to have malrotation without volvulus. The remaining 6 patients did not receive further imaging, and either were followed clinically (their symptoms resolved) or underwent surgical exploration that revealed other causes of abdominal pain.

The authors noted that unlike UGI, US does not expose the child to radiation or fill his or her stomach with contrast. In addition, US offers portability and repeatability (Wong K, et al. J Pediatr Surg. 2020;S0022- 3468(20)30295-5. Online ahead of print.).

Thoughts from Dr. Farber

Anything that can be done noninvasively at the bedside is a tremendous boon, both in terms of minimizing risk and getting a child to the operating room sooner when needed. The ultrasound is taking on more of the functions of a Star Trek tricorder every day.

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