Abernethy malformation: beware in cases of unexplained hepatic encephalopathy in adults—case report and review of the relevant literature

Abstract

The Abernethy malformation consists of a congenital extrahepatic portosystemic shunt and is believed to be extremely rare in humans. The potential implications of abnormal portovenous shunting and decreased hepatic portal flow are numerous and potentially serious. Although congenital extrahepatic portosystemic shunts are increasingly suspected and diagnosed in specialized centres, much of their clinical presentation and natural history is not fully understood. Symptoms of portosystemic shunt are mainly caused by increased levels of ammonia, which lead to signs of encephalopathy. Therapeutic options depend on the type of shunt and its clinical course, so the classification of the congenital portosystemic shunt is a key finding in these patients.

Abernethy malformation: Our experience from a tertiary cardiac care center and review of literature

“…The complicated development of the vena cava, its close relationship with the development of the vitelline vein and the abnormal development of these vessels during this stage may explain the occurrence of this rare congenital extrahepatic portosystemic anastomosis. [45]…”

Type II Abernethy Malformation: A Rare Cause of Hepatic Encephalopathy in Adulthood

“…Type I (end-to-side shunt) is characterized by complete extrahepatic shunting of portal blood into a systemic vein, with absent intrahepatic portal venous branches. Type II (side-to-side) are partial shunts between the portal vein and the systemic venous circulation, usually with the intrahepatic portal vein intact but hypoplastic [1,2] . Its actual prevalence is unknown.…”

“…One of the first manifestations can be hepatic encephalopathy of unknown cause [2] . This was the case with our patient, where Abernethy malformation type II was detected during the investigation.…”

“…However, in most of the published literature, which is mainly focused on paediatric populations, early shunt closure is advised to avoid complications. In adulthood, there are fewer reported cases [1,2] . The optimal therapeutic strategy is unclear in elderly patients with chronic hyperammonaemia and encephalopathy.…”

Abernethy malformation and hepatocellular carcinoma: a serious consequence of a rare disease

“…Additionally, the actual incidence in the general population is unknown. The diagnosis is mostly incidental9 and has been on the rise in recent years owing to advances in imaging techniques and their availability 10…”