Portal-systemic encephalopathy after Fontan-type operation in patient with polysplenia syndrome

Abstract

An 18-year-old patient, who had polysplenia and single ventricle, presented with altered mental status 9 years after a Fontan-type operation and pacemaker implantation. He underwent replacement of common atrioventricular valve and aortic valve plasty 1 year previously and has been placed on multiple medications including beta-blocker for his poor ventricular function. Blood chemistry revealed hyperammonemia of 2420 microg/l as a cause of this altered mental status disturbance. Superior mesenteric arteriography revealed large portal-systemic shunts in venous phase as a cause of hyperammonemia. To control blood ammonia level, we placed him on low protein diet, oral polymixin B, and lactulose instead of closing shunt with device. This case illustrates that portal-systemic shunt may result in hyperammonemia leading to altered mental status long after a Fontan-type operation.

Congenital Portosystemic Venous Connections and Other Abdominal Venous Abnormalities in Patients with Polysplenia and Functionally Univentricular Heart Disease: A Case Series and Literature Review

“…There are fewer reports of Abernethy malformation type 2, although this may be a function of differences in ascertainment rather than incidence 18,51 . Among the reported patients with an extrahepatic congenital PSVC, many were noted to have intrapulmonary arteriovenous shunting, and almost all of the patients with intrapulmonary arteriovenous shunting had polysplenia and interruption of the IVC 4–26 (Table 1). However, in most of the other reported cases of complete or partial PSVC, there was no mention of hypoxemia or intrapulmonary arteriovenous shunting, so the frequency of association between PSVCs and PAVMs is difficult to determine.…”

“…However, in most of the other reported cases of complete or partial PSVC, there was no mention of hypoxemia or intrapulmonary arteriovenous shunting, so the frequency of association between PSVCs and PAVMs is difficult to determine. In addition, many of the reported patients with congenital PSVC without clinically important intrapulmonary shunting have had polysplenia, 11,12,14,16–18 and there are several reported patients with polysplenia and intrapulmonary arteriovenous shunting but no documented PSVC, congenital heart disease, or biliary atresia 35 . A deeper understanding of the associations between polysplenia, congenital PSVCs, biliary atresia, and PAVMs is elusive, as the literature on this topic consists primarily of case reports, which represent a variety of subspecialty perspectives.…”

“…However, abnormalities of abdominal venous anatomy may be important in some patients with heterotaxy. For example, congenital portosystemic venous connections (PSVCs), which are rare in the general population, may occur with higher frequency in patients with polysplenia syndrome or features thereof, based on a number of reports, including the seminal case described by Abernethy 4–26 . Also, the pediatric liver transplant literature suggests that a preduodenal course and hypoplasia of the portal vein are common in patients with polysplenia, which is present in ∼10% of patients with biliary atresia 9,24,27,28 .…”

Fontan-Associated Liver Disease: Pathophysiology, Staging, and Management

“…In FALD, hepatic encephalopathy is a poorly documented event that can be explained by preserved liver function, even in patients with cirrhosis. 4,58,64 However, the real incidence of this complication may be underestimated by the retrospective nature of most studies and the presence of other neurological complications in FALD (i.e., anoxic encephalopathy, cardioembolic stroke, and cognitive impairment).…”

Congestive Cardiac Hepatopathy

“…Variceal bleeding has been reported, which highlights the need for screening when signs of advanced liver disease or portal hypertension are present [90]. To date, only three cases of hepatic encephalopathy have been described [91,92].…”