Congenital extrahepatic portosystemic shunt (CEPS) occurs when the blood vessels that go to the liver do not form correctly during fetal development. Toxins, that are normally removed by the liver, build up in the blood stream and can lead to symptoms such as decreased oxygen to the brain (hypoxia) and loss of brain function (hepatic encephalopathy). Symptoms can vary from person to person, and some people with CEPS have no symptoms. There are two types of CEPS. In type 1, the blood vessels going to the liver are missing, resulting in almost no blood flow through the liver. In type 2, blood vessels going to the liver have abnormal connections leading to decreased blood flow to the liver.

The cause for CEPS is unknown, but it sometimes occurs along with other conditions such as Down syndrome or congenital heart disease. CEPS can be diagnosed by different kinds of imaging studies, including ultrasound and CT scan. Treatment is based on the symptoms, and may include surgery or liver transplant in severe cases. The long-term outlook for people with CEPS depends on the severity of symptoms and the presence of other health conditions.

The cause of congenital extrahepatic portosystemic shunts (CEPS) is unknown. Sometimes CEPS occurs along with other conditions such as polysplenia or congenital heart defects.