Sigmoid Volvulus Showing a “Whirl Sign” in Coronal and Sagittal Views of Computed Tomography
Year: 2013
Type: article
Abstract: To the Editor: Sigmoid volvulus is a closed loop obstruction caused by a clockwise or counterclockwise twist and torsion of the sigmoid colon on its mesocolic axis.1 Life-threatening ischemia or perforation may develop when the torsion compromises the blood supply. Diagnosis of certain cases can be difficult. The finding of a “whirl sign” on computed tomography (CT) is virtually pathognomonic and should be immediately recognized.2 The detection of the whirl sign can obviate further radiographic studies.3 Herein, we present a case of surgically confirmed sigmoid colon volvulus in an elderly man and analyze the CT appearances of obstruction. A 75-year-old man with a history of chronic constipation presented to the emergency department with a 4-day history of progressive abdominal pain, distention, and failure to pass flatus for the last 2 days. Physical examination revealed diffuse abdominal tenderness with rebound and no signs of abdominal rigidity or guarding. Vital signs were unremarkable, and laboratory studies were within normal limits. A plain abdominal radiography revealed a distended sigmoid loop with an inverted U configuration. The coronal CT view, without oral or intravenous contrast medium, revealed dilated loops of colon with a central whirl sign (Figure 1A). The sagittal view also demonstrated a mesenteric whirl sign typical of a sigmoid volvulus (Figure 1B). The man was taken to the operating room for exploratory laparotomy, which confirmed the diagnosis of sigmoid volvulus. Intraoperative findings were remarkable for a redundant sigmoid colon with multiple mesenteric twists of sigmoid mesentery. The sigmoid resection was followed by a primary anastomosis. The postoperative course was uneventful, and the man was discharged on postoperative day 22. His constipation was treated with laxatives, and the volvulus has not recurred after 3 years. Sigmoid volvulus is the twisting of the sigmoid colon around its mesentery, causing partial or complete bowel obstruction.4 The exact pathogenesis of sigmoid volvulus is unknown. Whether it is associated with chronic constipation remains unclear. Risk factors for the development of sigmoid volvulus include advanced age, chronic constipation, congenitally redundant sigmoid colon, postoperative abdominal adhesions,5 and use of certain psychotropic medications.4 In approximately 30–40% of sigmoid volvulus, plain abdominal films can be equivocal.1 Plain abdominal radiographs usually demonstrate a dilated sigmoid colon. CT may be helpful because it can identify correctly the presence and level of the obstruction in suspected cases of volvulus.6 The whirl results from the rotation of afferent and efferent bowel loops around the point of obstruction, resulting in a tightly twisted mesentery.7 The definitive treatment of sigmoid volvulus is resection of the sigmoid colon because individuals treated using decompression procedures have a risk of recurrence of at least 40%.8 Factors associated with poor prognosis include advanced age, delay in diagnosis, presence of intestinal infarction, peritonitis, and shock at presentation.9 Prompt diagnosis and early decompression are vital for optimal management of acute sigmoid volvulus. Thus, physicians need to be aware of the whirl sign on CT scans when abdominal X-ray films reveal gross colonic dilatation of unknown etiology. Such a sign may indicate the presence of colonic volvulus. Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the authors and has determined that the authors have no financial or any other kind of personal conflicts with this paper. Author Contributions: Jinling Ma, Li Chen, and Yutang Wang: preparation of manuscript. Qingyi Meng and Yuanyu Qian: design, critical revisions. All authors read and approved the final manuscript. Jinling Ma and Li Chen contributed equally to this work. Sponsor's Role: There was no sponsor for this letter.
DOI: 10.1111/jgs.12373
Institution: Chinese PLA General Hospital
Language: English
Subfield: Surgery
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W1997408709