Utility of the Sonographic Whirlpool Sign in Diagnosing Midgut Volvulus in Patients With Atypical Clinical Presentations

Objective. To illustrate cases of midgut volvulus in 7 children, of whom only 2 were neonates, diagnosed initially by sonography using the whirlpool sign, and to emphasize the importance of considering malrotation and midgut volvulus in the differential diagnosis of acute or chronic abdominal pain in those beyond the neonatal period, the usual time of presentation for midgut volvulus. Methods. The sonography computer database of a large pediatric hospital was reviewed over a 26‐month period for sonographic reports that contained the key words midgut volvulus and whirlpool sign. From November 1999 until January 2002, 7 patients had a sonographic diagnosis of midgut volvulus on the basis of the whirlpool sign. Sonographic and surgical records of these patients were reviewed retrospectively. In addition, the department computer database of all contrast‐enhanced upper gastrointestinal examinations performed over the same period was searched using the key words midgut volvulus, and an additional 2 cases of midgut volvulus were found, neither of which had undergone a prior or subsequent sonographic study. Results. Seven patients, ranging in age from 1 day to 5½ years were found to have the whirlpool sign on sonography performed for acute abdominal symptoms, including projectile nonbilious emesis, colicky abdominal pain with suspicion of intussusception, palpable abdominal masses, right lower quadrant abdominal pain with suspected appendicitis, and chronic diarrhea. Six of the 7 cases of midgut volvulus were confirmed with upper gastrointestinal examinations. One patient was taken directly to surgery on the basis of the sonographic findings alone. One patient had subsequent computed tomography of the abdomen for continued suspicion of an abdominal mass. All 7 cases were confirmed as midgut volvulus at surgery. Conclusions. The sonographic whirlpool sign is a valid and highly sensitive sign for the diagnosis of midgut volvulus secondary to malrotation, and sonographers should be aware that it frequently occurs beyond the neonatal period with symptoms other than bilious emesis.