A Mysterious Case of Recurrent Confusion - An Unusual Presentation of Congenital Intrahepatic Portosystemic Shunt

Sep 29, 2026

Congenital portosystemic shunts (CPSS) are rare vascular malformations that divert portal blood into the systemic circulation, bypassing hepatic metabolism. While usually diagnosed in infancy, adult presentations are exceptional and diagnostically difficult. A 71-year-old woman had recurrent confusion and drowsiness with markedly elevated serum ammonia despite normal liver function. Extensive workup excluded infective, metabolic, and structural causes, and triple-phase liver CT showed intrahepatic portosystemic shunts with aneurysmal dilation, consistent with congenital origin. Due to comorbidities, she was managed medically with lactulose, rifaximin, sodium benzoate, glycerol phenylbutyrate, and L-ornithine L-aspartate, with no further encephalopathy on follow-up, highlighting the need for early recognition and multidisciplinary care.

LanguageEnglish

CategoryHealthcare

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Pages6

Reading Time15 min

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Abstract

Introduction

Case Presentation

Investigations

Review began 11/11/2025 Review ended 12/01/2025 Published 12/06/2025 © Copyright 2025 Shah et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited. DOI: 10.7759/cureus.98579 Open Access Case Report A Mysterious Case of Recurrent Confusion: An Unusual Presentation of Congenital Intrahepatic Portosystemic Shunt Fatma Shah 1, Anesa Noor 2 , Natasha Wahedna 1, Dipesh Chauhan 3, Muhammad Shahzad 1 1. Gastroenterology, Northampton General Hospital, Northampton, GBR 2. Internal Medicine, Leicester Royal Infirmary, Leicester, GBR 3. Pharmacy, Northampton General Hospital, Northampton, GBR Corresponding author: Fatma Shah, [fatma.shah1@nhs.net](fatma.shah1@nhs.net) Abstract Congenital portosystemic shunts (CPSS) are rare vascular malformations that divert portal blood into the systemic circulation, bypassing hepatic metabolism. Although typically diagnosed in infancy due to associated congenital anomalies or complications such as hepatic encephalopathy, adult presentations are exceptionally uncommon and diagnostically challenging. We report a 71-year-old female patient with recurrent episodes of confusion and drowsiness who was found to have markedly elevated serum ammonia levels despite normal liver function. Extensive investigations excluded infective, metabolic, and structural causes, and a triple-phase liver computed tomography (CT) revealed multiple intrahepatic portosystemicshunts with aneurysmal dilatation, consistent with congenital origin. Due to multiple comorbidities, the patient was deemed unsuitable for shunt closure or liver transplantation but responded well to medical therapy with lactulose, rifaximin, sodium benzoate, glycerol phenylbutyrate, and L-ornithine L-aspartate, with no further episodes of encephalopathy on follow-up. This case underscores the importance of considering CPSS in adults presenting with hyperammonaemia and altered mental status in the absence of hepatic disease. Early recognition and multidisciplinary management are key to preventing recurrence and optimising outcomes. Categories: Radiology, Internal Medicine, Gastroenterology Keywords: ammonia level, congenital liver diseases, congenital porto-systemic shunt, hepatic encephalopathy, lornithine-l-aspartate, porto-systemic shunt Introduction Congenital portosystemic shunts (CPSS) are rare developmental vascular anomalies that permit portal venous blood to bypass hepatic metabolism and drain directly into the systemic circulation [1] . They may be intrahepatic or extrahepatic and are often identified in infancy or childhood due to their association with other congenital anomalies, such as cardiac malformations or chromosomal syndromes. Adult presentations are exceptionally uncommon and can present a significant diagnostic challenge, particularly in the absence of overt hepatic disease. The clinical spectrum of CPSS varies widely from asymptomatic cases to severe complications such as hyperammonaemic encephalopathy, pulmonary hypertension, and hepatic nodular lesions [2] . Diagnosis typically requires high-resolution cross-sectional imaging, including computed tomography (CT) or MRI with intravenous contrast. Management depends on the severity of symptoms, anatomical type of shunt, and hepatic function. Conservative approaches involve ammonia-lowering therapies (lactulose, rifaximin, sodium benzoate, or Lornithine L-aspartate (LOLA)) and dietary protein modification. In refractory or anatomically suitable cases, interventional shunt closure via embolisation may be attempted, whereas liver transplantation remains an option in cases that are not amenable to closure. This report describes a rare case of congenital intrahepatic portosystemic shunts (CIPSS) presenting in late adulthood, managed successfully with medical

FAQs

What is congenital intrahepatic portosystemic shunt and why is it hard to diagnose in adults?

Congenital portosystemic shunts divert portal blood into systemic circulation, bypassing hepatic metabolism. Adult presentations are exceptionally uncommon and diagnostically challenging, especially when overt hepatic disease is absent.

How was the cause of recurrent confusion determined in this case?

Serum ammonia was markedly elevated despite normal liver function. After extensive investigations excluded infective, metabolic, and structural causes, triple-phase liver CT identified multiple intrahepatic portosystemic shunts with aneurysmal dilation consistent with congenital origin.

Why was shunt closure or transplantation not pursued, and what treatment worked?

Given multiple comorbidities, the patient was deemed unsuitable for shunt closure or liver transplantation. Medical therapy with lactulose, rifaximin, sodium benzoate, glycerol phenylbutyrate, and L-ornithine L-aspartate led to good response with no further encephalopathy during follow-up.

Sep 29, 2026

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