2295 Shunt Hunting: A Case of Long-Standing Encephalopathy Secondary to Anatomic Porto-Systemic Shunt

Abstract

INTRODUCTION: Abernethy malformation is a very rare congenital vascular malformation defined by diversion of portal blood away from liver [1]. Morgen and Superina classified extrahepatic portosystemic shunt into 2 types, as seen in Table 1 [3]. We describe in this case a type II extrahepatic portosystemic shunt. CASE DESCRIPTION/METHODS: A 67-year-old female with history of untreated hepatitis C, major depression disorder, hypertension, peripheral vascular disease, GERD, rheumatoid arthritis and HFrEF was admitted for altered mental status and elevated ammonia level on outpatient labs. This patient has a longstanding history of unexplained encephalopathy and elevated ammonia, treated with lactulose. She has no known history of cirrhosis and denied fevers, chills, nausea, vomiting or GI bleed. Patient was hypertensive on admission at 173/89, tachycardic to 109 and afebrile. She was saturating 98% on 2L O2. Exam was significant for bilateral coarse crackles, RUQ and epigastric tenderness and JVD. Ammonia was 106 on admission. Alkaline phosphatase 112, ALT 39, AST 84. Abdominal ultrasound revealed mildly heterogenous echogenicity of the liver with no evidence of cirrhosis. CT Abdomen was significant for congenital abnormalities including intestinal malrotation, hypoplastic IVC and abnormal pelvic variceal communication with the internal iliac vein, splenic vein and portal venous system (image). Patient underwent transjugular biopsy of liver with hepatic wedge pressures measured at 29 mmHg (gradient 14 mmHg). Pathology showed bridging fibrosis consistent with chronic viral hepatitis infection. Her encephalopathy improved to baseline after treatment with lactulose. DISCUSSION: We present a case of long-standing encephalopathy without cirrhosis, treated with lactulose. The patient also had markedly elevated hepatic portal pressures in the setting of HFrEF, without findings of cirrhosis on pathology. On this admission, CT abdomen/pelvis revealed an anatomic porto-systemic shunt, revealing the etiology of the patient’s unexplained “hepatic” encephalopathy. Multiple intra-abdominal congenital abnormalities were found on CT abdomen/pelvis, including a hypoplastic IVC, intestinal malrotation, and most significantly abnormal variceal communication with the internal iliac vein, splenic vein and portal venous system. The patient's collateral portosystemic shunts describes a type II extrahepatic portosystemic shunt.