Massive hemobilia from hepatic artery pseudoaneurysm

Clinical History

45 years old male presented to the ER with severe right hypochondrial pain and vomiting. Investigation revealed elevated total bilirubin and normal serum amylase. Abdominal ultrasound was performed and revealed distended gall bladder with turbid contents and mild ascites. The patient received blunt abdominal trauma 4 months ago.

Imaging Findings

The patient was referred to contrast enhanced CT abdomen. Figure 1 revealed distended gall bladder with thickened wall (curved arrow) and high density content (around 60 HU). Also there was smudged fat around its fundus (white arrowheads) and small amount of subhepatic fluid. Figure 2 revealed a small rounded enhanced structure representing the pseudo aneurysm related to the GB and measures 1.5 cm in diameter. It displayed less enhancement than the aorta in arterial phase and more than the portal vein in venous phase and turned isodense to vessels in delayed phase. Figure 3 illustrated the neck of the pseudo aneurysm (black arrow) and nearby right hepatic artery. Sets of images in Figure 4 of the arterial phase revealed an anomalous origin of the hepatic artery. The right hepatic artery arose directly from the abdominal aorta (replaced right hepatic artery) while the left hepatic artery arose from the coeliac trunk.

Discussion

Hemobilia is the presence of blood inside the biliary tree. Massive hemobilia is rare life threatening condition that is caused by rupture aneurysm or pseudo aneurysm, liver trauma or iatrogenic following cholecystectomy. [1]
The patient stated that he had blunt abdominal trauma due to motorcycle accident while driving his bike when a car hit him. He stayed for a day in hospital under observation and initial abdominal ultrasound was unremarkable.
Contrast enhanced CT is the imaging modality of choice for the diagnosis and follow up of post traumatic abdominal injuries. It can assess the liver parenchyma, its vascular supply and retroperitoneal structures. [2] One of the uncommon delayed complications of liver trauma is the development of pseudo aneurysm. Due to its high risk of rupture, and hence risk of mortality, hepatic pseudo aneurysm should be treated as early as possible. Trans-arterial embolization (TAE) via per cutaneous route using coils is the method of choice in treating such cases with a success rate of 70-100%.[2]
The narrow neck of the aneurysm in this case is responsible for its enhancement pattern which appears less than the aorta in arterial phase due to slower filling and more than the portal vein in venous phase due to delayed emptying.
Pathological specimen of the gall bladder confirmed the presence of abundant blood cells within the GB lumen and excluded the presence of inflammatory cells at its wall. The gall bladder wall also showed an adherent rounded thrombus which arose from focal laceration of wall of an adjacent small artery that confirmed the radiological diagnosis of pseudo aneurysm.
Variation of the coeliac axis and hepatic arteries occurs in up to 50% of patients for which Michel's classification classifies ten variant subtypes. [3] Replaced right hepatic artery originates directly from the aorta, as in this case, is a very rare variant that is not consistent with Michel's classification subtypes and hence is considered unclassified. Its frequency is estimated to be 1.8% according to Kobb et al. [4]
The patient deteriorated rapidly after admission and unfortunately died in few hours before planning for angiographic intervention, in this case showing the need of very acute workup and therapy.

Differential Diagnosis List

Final Diagnosis

Massive hemobilia due to rupture hepatic artery pseudo aneurysm

URL:	https://www.eurorad.org/case/11225
DOI:	10.1594/EURORAD/CASE.11225
ISSN:	1563-4086