Intrahepatic Air: Pneumobilia vs. Portal Venous Gas

Abstract

The finding of intrahepatic air on computed tomography scan is a potentially ominous radiographic sign that is usually attributed to either pneumobilia or portal venous gas. In this article, we present a case of each of the aforementioned conditions. Pneumobilia is typically visualized as a large confluence of air located within the central portion of the liver and is most commonly seen in patients following procedures involving the biliary tract. Management may be either surgical or non-operative, depending on the etiology and clinical presentation. Portal venous gas manifests as small air densities in the periphery of the liver located predominantly in the left lobe. This entity is most commonly caused by mesenteric ischemia and carries a mortality rate of 75-90%. Treatment entails emergent laparotomy with possible resection of the affected segment of bowel. In the absence of findings of bowel ischemia, portal venous gas may be managed non-operative. Early diagnosis and treatment is based on correlation of the clinical presentation and a high index of suspicion on radiographic evaluation. CT findings of intrahepatic air should be carefully evaluated to determine an appropriate course of clinical management.