Gas in the portomesenteric vessels from nonocclusive ischemic bowel disease
===========================================================================

* Isabelle Nault
* Claude Lauzon

*   © 2007 Canadian Medical Association or its licensors

**What's your call?** 

![Figure1](http://www.cmaj.ca/https://www.cmaj.ca/content/cmaj/176/3/321.3/F1.medium.gif)

[Figure1](http://www.cmaj.ca/content/176/3/321.3/F1)

Figure. Plain film radiograph of a 52-year-old woman with known Crohn's disease who presented with acute abdominal pain and hypotension.

A woman with known Crohn's disease and a previous partial resection of her small intestine presented with a poor appetite, weight loss, diarrhea and malnutrition. She was an ex-smoker and was taking antihypertensive therapy. Results of an upper gastrointestinal series showed stenotic areas in the ileum. The patient was admitted to hospital with a presumed exacerbation of inflammatory bowel disease. However, acute abdominal pain and distension developed despite treatment, and she became hypotensive and nonresponsive. Resuscitation efforts were initiated, and a nasogastric tube was inserted which drained bloody fluid. A plain abdominal radiograph (Fig. 1) showed air in the portomesenteric vascular system. Gastroscopy was performed and showed extensive mucosal ulcerations. An emergency laparotomy revealed zones of necrosis throughout the small intestine and bowel; however, no curative treatment could be done, and the woman died shortly after withdrawal of life support. Autopsy revealed extensive nontransmural gastric ulcers, necrotic areas in the small and large intestines, and nonocclusive atheromatous plaques in the aorta and at the origin of the inferior mesenteric artery. The final diagnosis was ischemic en-terocolitis due to nonocclusive arterial stenosis and diffuse atheromatosis.

![Figure2](http://www.cmaj.ca/https://www.cmaj.ca/content/cmaj/176/3/321.3/F2.medium.gif)

[Figure2](http://www.cmaj.ca/content/176/3/321.3/F2)

**Fig. 1:** Plain film radiograph showing air in the portomesenteric circulation (arrows).

The presence of gas in the porto-mesenteric circulation is an uncommon sign of ischemic enterocolitis, but its significance should not be overlooked. Gas is thought to enter the portomesenteric circulation following an injury to the gastrointestinal tract. This is most often due to mesenteric ischemia but may also occur following ulceration of the mucosa or abdominal sepsis. Portomesenteric venous gas can be differentiated from biliary gas by its location: portomesenteric gas is peripheral and extends near or out of the hepatic capsula, whereas biliary gas is more central because of the centripetal flow of bile.1

Nonocclusive, or nongangrenous, ischemic colitis occurs when blood flow through small watershed vessels is altered by a variety of conditions, including severely low blood flow due to nonobstructive stenosis, shock, small-vessel disease, vasospasm, hypercoagulable states and use of certain medication, such as cocaine, ergotamine, amphetamine, pseudoephedrine, vasopressin, sumatriptan, oral contraceptive (venous thrombosis) and digitalis. The cause of ischemic enterocolitis in this patient was partial obstruction of the inferior mesenteric artery and diffuse small-artery disease throughout the distal mesenteric microcirculation. Non-occlusive ischemic colitis can present similarly to Crohn's disease with a subacute pattern of mild repeated injury (chronic enteritis). However, it is more commonly heralded by the sudden onset of severe crampy abdominal pain and diarrhea mixed with bright red blood and occasionally melena. The abdomen is often distended, and bowel sounds are usually present. Peritoneal signs are absent unless necrosis becomes transmural. The diagnosis can be confirmed by imaging (urgent doppler ultrasonography of mesenteric vessels, CT scanning, conventional or magnetic resonance angiography). In the absence of spontaneous resolution with supportive measures, treatment of strictures and ulceration is often surgical and has mixed results.

## Footnotes

*   **Competing interests:** None declared.

## REFERENCE

1.  1. Sebastia C, Quiroga S, Espin E, et al. Portomesenteric vein gas: pathologic mechanisms, CT findings and prognosis. Radiographics 2000;20:1213-24.
    
    [CrossRef](http://www.cmaj.ca/lookup/external-ref?access_num=10.1148/radiographics.20.5.g00se011213&link_type=DOI) 
    
    [PubMed](http://www.cmaj.ca/lookup/external-ref?access_num=10992012&link_type=MED&atom=%2Fcmaj%2F176%2F3%2F321.3.atom) 
    
    [Web of Science](http://www.cmaj.ca/lookup/external-ref?access_num=000171509700002&link_type=ISI)