II. Causes: Pneumobilia (Biliary Ductal Gas)
- Background
- Bile duct does not typically fill with IV contrast (as opposed to Portal Vein)
- Pneumobilia is typically limited to the central liver near the hilum (sparing the peripheral ducts)
- In-situ gas production within biliary ducts
- Communication between biliary ducts and bowel
- Cholecystectomy
- ERCP
- Sphincter of Oddi incompetence
- Enteric-biliary fistula (spontaneous or surgical)
- Gas introduction from other iatrogenic site
- Liver biopsy
- Biliary duct percutaneous procedure
III. Causes: Hepatic Portal Venous Gas (HPVG)
- Precautions
- HPVG is an ominous finding, implying a acutely life-threatening condition
- HPVG is associated with <25% survival rate
- Portal Vein normally fills with contrast
- Most common
- Intestinal Ischemia or infarction (75%)
- Less common
- Abdominal or retroperitoneal abscess
- Ascending Cholangitis (or other biliary infection)
- Blunt Abdominal Trauma
- Gastric or Duodenal Ulcer
- Iatrogenic (e.g. Jejunostomy tube placement)
- Inflammatory Bowel Disease
- Necrotizing peritonitis
IV. Imaging
-
CT Abdomen with contrast
- Although contrast does not augment gas identification, contrast highlights surrounding vessels and organs
- Gas acts as a Contrast Material on CT, differentiating body fat (-100 HU) and water (0 HU)
- Gas has a very low density on CT (-1000 HU)
V. References
- Broder (2026) Crit Dec Emerg Med 40(8): 27-9
- Sheikh (2021) Cureus 13(4):e14486 +PMID: 34007742 [PubMed]