Rectal arterio-portal fistula: An unusual cause of persistent bleeding per rectum following a proximal spleno-renal shunt

Abstract

Gastrointestinal arterio-venous malformations are a known cause of gastrointestinal bleeding. We present a rare case of persistent rectal bleeding due to a rectal arterio-portal venous fistula in the setting of portal hypertension secondary to portal vein thrombosis. The portal hypertension was initially surgically treated with splenectomy and a proximal splenorenal shunt. However, rectal bleeding persisted even after surgery, presenting us with a diagnostic dilemma. The patient was re-evaluated with a computed tomography mesenteric angiogram which revealed a rectal arterio-portal fistula. Arterio-portal fistulas are a known but rare cause of portal hypertension, and possibly the underlying cause of continued rectal bleeding in this case. This was successfully treated using angiographic localization and super-selective embolization of the rectal arterio-portal venous fistula via the right internal iliac artery.The patient subsequently went on to have a full term pregnancy. Through this case report, we hope to highlight awareness of this unusual condition, discuss the diagnostic workup and our management approach.

Keywords: Portal hypertension, Esophageal varices, Splenorenal shunt, Arteriovenous malformations, Portal vein thrombosis

Core tip: We present a rare case of persistent rectal bleeding due to a rectal arterio-portal venous fistula, in the setting of portal hypertension. Through this case report, we hope to highlight awareness of this unusual condition, and discuss the diagnostic workup and our subsequent management. We believe that this is the first of such cases reported in the literature.