Recommended Citation
Muench J, Falesch L, MacDonald W. Congenital Extrahepatic Portosystemic Shunt as a Possible Cause of Chronic Encephalopathy. Presented at Scientific Day; May 20, 2026; Milwaukee, WI.
Abstract
Introduction/Background:
Congenital extrahepatic portosystemic shunt, also termed Abernethy malformation, refers to abnormal drainage of the portal circulation into a systemic vein (e.g., inferior vena cava). Abernethy malformation remains a rare entity, with only a few hundred cases reported in the literature. Among many associated congenital malformations and acquired complications of Abernethy malformation, chronic encephalopathy may also develop as portal venous blood bypasses the liver and certain metabolites, namely ammonia, escape filtration. Vascular abnormalities are not often considered in the evaluation of chronic encephalopathy. However, we present here the case of a 31-year-old patient found to have Abernethy malformation and discuss the possible contribution of the vascular abnormality toward the patient’s longstanding developmental delay.
Description:
A 31-year-old female with history of developmental delay presented to the emergency department with several days of vague abdominal pain and hematemesis. Initial physical exam and vital signs were reassuring. Lab work was unremarkable, apart from elevated total bilirubin, AST, and alkaline phosphatase. An initial CT of the abdomen and pelvis was obtained, which demonstrated abnormal liver morphology with a poorly defined hepatic mass, sequelae of portal hypertension, and most notably a non-visualized portal vein. Over the course of the patient’s admission, robust imaging workup (including ultrasound, CT, and MRI) identified abnormal emptying of the portal venous system into the inferior vena cava, consistent with Abernethy malformation. The patient’s hematemesis was secondary to erosive portal hypertensive gastropathy diagnosed via EGD, which was subsequently treated. While admitted, Psychology was also consulted to further assess the possible contribution of newly diagnosed Abernethy malformation toward the patient’s developmental delay. The patient was discharged with Hepatology and Gastroenterology follow-up for further management of the identified vascular abnormality.
Discussion:
Through a multi-modal imaging approach, this patient was diagnosed with Abernethy malformation. Although rare, vascular anomalies should be considered as a potential cause of chronic encephalopathy and developmental delay, and imaging may play a role in their detection. Further understanding of the body’s adaptive mechanisms to congenital extrahepatic portosystemic shunt may lead to better recognition of chronic encephalopathy presenting as developmental delay.
Presentation Notes
Presented at Scientific Day; May 20, 2026; Milwaukee, WI.
Full Text of Presentation
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Document Type
Poster
Open Access
Available to all.
Congenital Extrahepatic Portosystemic Shunt as a Possible Cause of Chronic Encephalopathy
Introduction/Background:
Congenital extrahepatic portosystemic shunt, also termed Abernethy malformation, refers to abnormal drainage of the portal circulation into a systemic vein (e.g., inferior vena cava). Abernethy malformation remains a rare entity, with only a few hundred cases reported in the literature. Among many associated congenital malformations and acquired complications of Abernethy malformation, chronic encephalopathy may also develop as portal venous blood bypasses the liver and certain metabolites, namely ammonia, escape filtration. Vascular abnormalities are not often considered in the evaluation of chronic encephalopathy. However, we present here the case of a 31-year-old patient found to have Abernethy malformation and discuss the possible contribution of the vascular abnormality toward the patient’s longstanding developmental delay.
Description:
A 31-year-old female with history of developmental delay presented to the emergency department with several days of vague abdominal pain and hematemesis. Initial physical exam and vital signs were reassuring. Lab work was unremarkable, apart from elevated total bilirubin, AST, and alkaline phosphatase. An initial CT of the abdomen and pelvis was obtained, which demonstrated abnormal liver morphology with a poorly defined hepatic mass, sequelae of portal hypertension, and most notably a non-visualized portal vein. Over the course of the patient’s admission, robust imaging workup (including ultrasound, CT, and MRI) identified abnormal emptying of the portal venous system into the inferior vena cava, consistent with Abernethy malformation. The patient’s hematemesis was secondary to erosive portal hypertensive gastropathy diagnosed via EGD, which was subsequently treated. While admitted, Psychology was also consulted to further assess the possible contribution of newly diagnosed Abernethy malformation toward the patient’s developmental delay. The patient was discharged with Hepatology and Gastroenterology follow-up for further management of the identified vascular abnormality.
Discussion:
Through a multi-modal imaging approach, this patient was diagnosed with Abernethy malformation. Although rare, vascular anomalies should be considered as a potential cause of chronic encephalopathy and developmental delay, and imaging may play a role in their detection. Further understanding of the body’s adaptive mechanisms to congenital extrahepatic portosystemic shunt may lead to better recognition of chronic encephalopathy presenting as developmental delay.
Affiliations
Aurora St. Luke's Medical Center