Recurrent Hepatic Encephalopathy Due to Spontaneous Mesocaval Shunt

Abstract

Spontaneous portosystemic shunting is a rare entity that can manifest as hepatic encephalopathy (HE) in longstanding liver disease. In cases of severe portal hypertension (pHTN) portal blood flow may reverse with shunting from the portal vein to the inferior vena cava through a portosystemic anastomosis. Shunting allows toxins to accumulate in the systemic circulation leading to encephalopathy. We present a case of spontaneous mesocaval shunting in a patient with recurrent HE. A 76 year old female with history of Hepatitis B cirrhosis, grade II varices, and multiple admissions for HE presented for acute altered mental status for 1 day. At baseline, she is functionally independent and takes lactulose, rifaxamin, nadolol, entecavir, spironolactone, furosemide, and omeprazole. On presentation, she was not alert or orientated, minimally responsive to voice, moving only to pain, eye-blink startle reflex present but without tracking. There were facial spider angiomas, but no jaundice, ascites or asterixis. She was hemodynamically stable with mild pan-elevation of liver tests, hyperammonemia, hypoalbuminemia, macrocytosis with thrombocytopenia and mild coagulopathy. Prior work-up was limited to head CT and abdominal ultrasound due to acute kidney injury, and negative infectious work-up. CT abdomen on presentation revealed stable appearance of cirrhotic liver, as well as pHTN including recanalization of the umbilical vein, esophageal and omental varices, and mesocaval shunt adjacent to the left portal vein consistent with AV shunting. Interventional radiology was consulted for closure of the shunt and after 3 days of medical therapy, her mental status improved to baseline. Initial attempt was unsuccessful in catheterizing the shunt through the inferior vena cava, while a second attempt through the transplenic portogram and embolization of mesocaval shunt was successful. Patient made a stable recovery after the intervention for discharge. Spontaneous mesocaval shunting is a rare collateral circulation that develops between the superior or inferior mesenteric veins and the inferior vena cava. Similar collateral vessels can manifest as patent paraumbical vessels arising from the left portal vein, as seen in this patient. A high index of suspicion in patients with HE with appropriate imaging is needed to make a diagnosis. Treatment of these shunts via occlusion is crucial in reducing the occurrence of recurrent HE in cirrhosis.2292_A Figure 1. Axial CT - Demonstrates large portosystemic shunt arising from the superior mesenteric vein with its confluence at the inferior vena cava. A transplenic approach was utilized to gain access into the portal system and the mesocaval shunt was subselected.2292_B Figure 2. Robust flow was noted on venograms through the shunt pre-embolization. The mesocaval shunt was embolized with multiple coils of varying sizes and with nBCA.2292_C Figure 3. Final venograms demonstrated complete occlusion of the shunt and preferential flow through to the portal vein post-procedure.