SBO Due to Umbilical Hernia

70F with abdominal pain • Xray of the Week

Figure 1. Describe the abdominal findings.

Figure 2.

A. Axial CT scan of the abdomen demonstrating small bowel obstruction secondary to umbilical hernia with collapsed small bowel distal to obstruction (yellow arrow).

B. Axial CT abdomen demonstrating dilated small bowel in C shape configuration (green arrow).

C. Sagittal CT abdomen demonstrating umbilical hernia outpouching from the abdominal wall. Outline of the hernia follows a C-configuration with small bowel contained within the hernial sac with inflammatory changes (blue arrow).

Discussion:

An abdominal wall hernia occurs when a portion of the bowel or peritoneum extends beyond the abdominal wall, resulting in a sac containing tissue or abdominal organs. Hernias can be classified as inguinal, femoral, incisional, umbilical, or epigastric (1). The most common ventral hernia is the umbilical hernia (3). An umbilical hernia occurs due to a defect in the anterior abdominal wall 3 cm above or below the umbilicus, as seen in Figure 1 (2). This abdominal defect is common among patients with increased intra-abdominal pressure due to pregnancy, ascites, or obesity, which weakens the abdominal musculature (2).

Common complications of abdominal wall hernias include small bowel obstruction (SBO) and bowel ischemia (3,4). An SBO is defined as a complete or partial blockage of the small intestine due to a functional or mechanical pathology as seen in Figure 1. This presents as abdominal pain, distension, nausea, vomiting, constipation, and high-pitched or absent bowel sounds. Further complications include hernia incarceration (irreducible sac) and strangulation (ischemia secondary to lack of blood supply) (3).

The use of CT imaging helps identify subtle signs of complications such as obstruction, incarceration, and strangulation (4). On CT imaging, key findings of an SBO include small bowel dilation, a transition point from dilated to nondilated small bowel, colon compression, and air-fluid levels (3, 5). In Figure 1, CT imaging demonstrates the umbilical hernia containing a portion of the small bowel in a C-shaped configuration. Narrowing of the hernial sac neck in addition to fat stranding on CT imaging also suggests hernia incarceration and inflammatory changes (3). Other associated findings of SBO secondary to a strangulated umbilical hernia include discrete mesenteric engorgement, ascitic fluid within the hernia sac, and dilation of herniated bowel loops (3).

If asymptomatic, abdominal wall hernias are typically not operated on. If complications arise, surgical treatment with laparoscopic repair or mesh is indicated (3, 4). ​​​​

References:

1. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-. Hernias: Overview. 2016 Sep 21 [Updated 2020 Jan 30]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK395554/

2. Coste AH, Jaafar S, Parmely JD. Umbilical Hernia. [Updated 2020 Jun 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2020 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459312/

3. Aguirre DA, Santosa AC, Casola G, Sirlin CB. Abdominal wall hernias: imaging features, complications, and diagnostic pitfalls at multi-detector row CT. Radiographics. 2005;25(6):1501-1520. doi:10.1148/rg.256055018

4. Baiu I, Hawn MT. Small Bowel Obstruction. JAMA. 2018;319(20):2146. doi:10.1001/jama.2018.5834

5. Paulson EK, Thompson WM. Review of small-bowel obstruction: the diagnosis and when to worry. Radiology. 2015;275(2):332-342. doi:10.1148/radiol.15131519

Rabab Zaidi is an aspiring radiologist and fourth year medical student at the Loyola University Chicago Stritch School of Medicine (SSOM). She currently serves as the Community Support Co-Lead for the Loyola University COVID-19 Response Team and Co-President of the Radiology Interest Group at SSOM. At the Stritch School of Medicine, she has also worked with the Department of Radiation Oncology to study prostate cancer imaging and adaptive radiotherapy techniques, where she learned about the intersection of patient care and radiology. Rabab graduated magna cum laude with a degree in Economics from Loyola University Chicago in 2016. She is further passionate about mentorship, advocacy, and photography.

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Kevin M. Rice, MD is the president of Global Radiology CME

Dr. Rice is a radiologist with Renaissance Imaging Medical Associates and is currently the Vice Chief of Staff at Valley Presbyterian Hospital in Los Angeles, California. Dr. Rice has made several media appearances as part of his ongoing commitment to public education. Dr. Rice's passion for state of the art radiology and teaching includes acting as a guest lecturer at UCLA. In 2015, Dr. Rice and Natalie Rice founded Global Radiology CME to provide innovative radiology education at exciting international destinations, with the world's foremost authorities in their field. In 2016, Dr. Rice was nominated and became a semifinalist for a "Minnie" Award for the Most Effective Radiology Educator.

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