The association of bleeding with combined ERCP and sphincterotomy has been reported to occur in up to 2% of patients with a prevalence of severe bleeding being 0.1-0.5% [7,8].

Vascular arterial aneurysms include true aneurysms stemming from the intrinsic vessel wall defect or a pseudoaneurysm arising from the manipulation of the pancreaticobiliary duct with duodenoscope during sphincterotomy or post-inflammation due to pancreatitis [9,10].

Pancreaticoduodenal and gastroduodenal artery aneurysms together account for only 3.5% of all aneurysms, while pancreatitis has been reported to be associated with aneurysms in almost half of the cases [11,12]. Pseudoaneurysm due to pancreatitis could stem from the direct enzymatic degradation of the vascular walls [13]. Another risk factor for the formation of pseudoaneurysm is cholangitis in patients who underwent cholecystectomy [14]. Li et al. have reported a patient who had undergone open cholecystectomy and developed cholangitis and pancreatitis which they suggest as precipitant towards the formation of pseudoaneurysm post-ERCP [15]. In our patient, there was no preceding cholecystectomy, and although he did have cholangitis that was managed with intravenous antibiotics, he did not develop pancreatitis. Li et al. concluded following the endoscopic and angiographic reviews that perhaps it was the guidewire-related injury within the left hepatic duct penetration that may have led to the ERCP-related formation of pseudoaneurysm and bleeding, as CT and magnetic resonance cholangiopancreatography (MRCP) imaging performed before ERCP did not disclose any hematoma or pseudoaneurysm [15]. 

Briefly, another reported reason for bleeding following ERCP in literature (although not in the case of our patient here) is the phenomenon of post-sphincterotomy bleeding managed with options including balloon tamponade, injection of diluted adrenaline of strength of 1:10,000, or spray irrigation [16]. The application of monopolar electrocautery in the vicinity of the duodenal papilla while avoiding the opening of the pancreatic duct at the 5 o'clock position is another mode for the management of post-ERCP bleeding [17]. The application of endoscopic clips with a duodenoscope is yet another mode of securing hemostasis. However, it is reported to be associated with technical difficulties with clip deployment as the plastic sheath may bend or get kinked while passing over the elevator located at the bottom of the instrument channel [16]. Although in some patients spontaneous thrombotic obstruction of the pseudoaneurysm has been reported [6], the interventional radiology-guided angiogram followed by the embolization of the pseudoaneurysm bleeding remains the choice of treatment due to the diagnostic precision and instant deliverance of the therapeutics [18]. The availability of less traumatic guidewires has now improved the avoidance of duodenoscope-related haemobilia [19], although in patients with persistent bleeding, surgery remains the last viable option [20]. Other recommendations to avoid pseudoaneurysm bleeding are to avoid going too far in the biliary tree with the guidewire during biliary cannulation [15].

Although there remains a limited possibility that our patient who did not have prior cholecystectomy may have suffered from the bleeding from the segmental branch of the hepatic artery pseudoaneurysm following biliary cannulation, it may have also resulted from cholangitis itself. Lastly, it could also be argued that perhaps the pseudoaneurysm may have been present beforehand as clots were seen during ERCP, although this is excluded from the CT done before ERCP that did not show any pseudoaneurysms.

It would be interesting to see more case reports to understand the phenomenon more decisively.