Severe abdominal pain in an 85 year old womanBMJ 2016; 355 doi: https://doi.org/10.1136/bmj.i5749 (Published 16 November 2016) Cite this as: BMJ 2016;355:i5749
- Joseph Dalby Sinnott, core surgical trainee1,
- David C Howlett, 2 consultant radiologist
- 1Department of Surgery, East Sussex Hospitals NHS Trust, Eastbourne, UK
- 2Department of Radiology, East Sussex Hospitals NHS Trust
- Correspondence to: J D Sinnott
An 85 year old woman was admitted to hospital with a rigid, mildly distended, severely painful abdomen and absent bowel sounds. She was in atrial fibrillation and was hypotensive. A computed tomography (CT) scan was performed. What does it show (fig 1⇓)?
The CT scan shows widespread peripheral branching gas within the liver. This is consistent with a diagnosis of portal venous gas, and in this case was secondary to small bowel ischaemia.
The non-contrast CT scan (fig 2⇓) shows widespread branching gas that is peripherally distributed within the hepatic portal venous system (P). This is known as portal venous gas or hepatic portal venous gas. The CT scan also shows fluid around the liver (F) and spleen. A nasogastric tube can be seen on the image within the stomach.
The main causes of portal venous gas are ischaemia and sepsis. In this case, small bowel ischaemia was confirmed. Rarely, portal venous gas is caused by other pathology, such as gross bowel distension or inflammatory bowel disease.
At present, the mechanisms by which portal venous gas forms are not completely understood. The gas is thought to form through a combination of intraluminal gas escaping through the wall of the colon and organisms that form gas within the venous system.1 Alterations to the intestinal wall are believed to facilitate this process.2
When gas is seen within the liver, pneumobilia (gas within the biliary system) should be considered as a differential diagnosis. Pneumobilia is often seen after endoscopic retrograde cholangiopancreatography, or where the sphincter of Oddi is incompetent. It is important to distinguish pneumobilia from portal venous gas because they have different causes. Radiologists distinguish the two by identifying whether the gas within the liver is located centrally or peripherally. In pneumobilia, the gas is seen centrally as it is pushed towards the hilum with the flow of bile.By contrast, portal venous gas is seen peripherally as it travels by the flow of blood. In addition to the distribution of the gas, the clinical history and secondary CT findings such as bowel ischaemia, sepsis, or an abscess, help in making the appropriate diagnosis.
This patient was not fit for surgery.
Competing interests: We have read and understood BMJ policy on declaration of interests and declare the following: none.
Provenance and peer review: Not commissioned; externally peer reviewed.
Patient consent not required (patient died, with no next of kin)