Ultrasound Case 076

Image 1: Transverse mid abdomen.

Two distended loops of fluid filled bowel are seen. Fluid makes the “to-and-fro’ motion typical of obstruction. You can imagine frustrated bowel peristalsing its content forward only to encounter obstruction. It then relaxes and fluid flows back to its original position.

Image 2: Oblique RUQ, liver and hepatic portal vein.

The liver parenchyma looks very unusual. The patchy areas of multiple punctate echogenic foci is typical of portal venous gas. Focus on the portal vein itself to see bubbles passing up the portal vein into the liver.

Bowel obstruction with hepatic portal venous gas (HPVG)

Gas can get into the portal venous system when the intraluminal pressure of bowel increases, and/or when the mucosal surface is breached. Ultrasound is highly sensitive for portal venous gas, and in this case the CT scan did not demonstrate any intrahepatic gas.

Portal venous gas is never a normal appearance, and portal venous gas demonstrated on other imaging modalities is considered catastrophic – usually due to ischaemic gut with mucosal breach, and established or impending sepsis due to translocation of gas and bacteria into the circulation.

The use of ultrasound in clinician’s hands has found this appearance is more common than we’d realised and occasionally resolves without operative intervention.

The ultrasound appearance alone should not mandate surgical management. It should alert the clinician and surgeon, expedite optimal management directed at the underlying pathology. Decisions should be supported usually with CT to define the underlying issue, broad spectrum antibiotics, decompression of the bowel (this case settled with a nasogastric tube), and consideration for surgical management if required.