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Strangulated transmesenteric small bowel internal hernia

Case contributed by Nolan Walker
Diagnosis certain

Presentation

Previous history of jejuno-ileal bypass for weight loss. Now has a painful, distended abdomen with vomiting. Bowel obstruction?

Patient Data

Age: 40 years
Gender: Female

The small bowel loops are seen lateral to the right colon and also anterior to the stomach. The appearances are likely to be due to an internal hernia probably through a defect in either the mesentery or transverse mesocolon.

Arterial supply to the small bowel appears normal.

The superior mesenteric vein is not enhancing. This is caused by the delayed venous return from the gut (venous congestion), again suggesting that the internal hernia is incarcerated and there is likely early strangulation. 

The correct position typically for jejuno-ileal anastomoses is the left upper quadrant and the fact that the anastomosis is in the right iliac fossa is concerning.

There is no small bowel dilatation. The stomach is not distended. The cecum is distended measuring 7.2 cm in maximum axial dimensions.

Note the stranding within the mesentery adjacent to the malpositioned cecum and the free fluid adjacent to this. In conjunction with the lack of enhancement of the portal vein, these findings are suggestive of incarceration of the internal hernia.

Single slice analysis

Annotated image

Analysis of key images.

  1. This is a key point in the imaging; the transverse colon is seen to project posteriorly and is strictured at the point marked.
  2. This image is taken further downstream and illustrates the strictured transverse colon.
  3. This image is taken further downstream and illustrates the strictured transverse colon. The transverse colon at this point is completely collapsed, anteriorly there is a mesenteric artery branch, which is seen to swirl as it is drawn in to opening of the internal mesenteric hernia.
  4. This image reveals the transition point of the transverse colon. 
    From the collapsed portion (red arrow) to the normally distend downstream segment (purple arrow), as the transverse colon exits the internal hernia's opening.
  5. This image shows the small bowel (blue arrow) situated lateral to the cecum (purple arrow) . This is abnormal and suggests an internal hernia.
  6. This image shows the small bowel (blue arrow) situated lateral to the cecum (purple arrow)  demonstrated more superiorly in the abdomen.
  7. The image reveals the collapsed fundus of the stomach (purple arrow), to be situated posterior to the small bowel (blue arrow). This is abnormal and suggests an internal hernia.
  8. This triangular configuration of the small bowel represents where the jejunum is bowel is drawn into the internal hernia.
  9. The strictured segment of transverse colon seen in a single coronal slice. This is the point where the cecum, small and large bowel pass through the internal hernial orifice.
  10. Coronal imaging depicting the abnormal positioning of the small and large bowel in the right iliac fossa. Which raises the possibility of a small bowel internal hernia.
  11. This is the suspected opening orifice for the small bowel internal hernia.

Case Discussion

As per the operation note (see below), the CT findings were confirmed on laparotomy.

The features on the CT demonstrate conclusively that this is an internal hernia, probably iatrogenic, secondary to the previous jejuno-ileal anastomosis.

The CT features cataloged above are all indicative of a mesenteric internal hernia which is incarcerated and has CT findings of early strangulation. These can occur spontaneously or secondary to surgery.

Surgical operation note (abridged):

Laparoscopic converted to open reduction of internal hernia and closure of the mesenteric defect.

Finding: Jejuno-ileal bypass, mesenteric defect open. All of common channel, right colon and mid transverse herniated through mesenteric defect of jejuno-ileal anastomosis with evidence of venous congestion and large bowel obstruction. Free purulent fluid in pelvis.

Procedure: attempt at lap reduction of hernia not possible - decision to convert. Common channel, right colon and mid transverse reduced. All pinked up once reduced. All viable. Mesenteric defect closed.

Case presented with:

Dr Tony Booth FRCR, Radiology Reporting Online  

Mr Marco Adamo MD, Laparoscopic Bariatric Surgeon

Ms Jihene El Kafsi FRCS, Bariatric Fellow

UCLH Bariatric Center for Weight Management and Metabolic Surgery

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