Congenital intrahepatic portosystemic venous shunt presenting with paraparesis as the initial symptom

An 85-year-old woman was hospitalized with rapidly progressive paraparesis without altered consciousness, although she was not definitively diagnosed. She developed acute drowsiness and disorientation several days later. An intrahepatic portosystemic venous shunt (IPSVS) was observed on enhanced computed tomography, and hyperammonemia suggested leakage of neurotoxins from the shunt as the etiology of the patient's symptoms. Her neurological symptoms and hyperammonemia improved following transcatheter shunt embolization. We diagnosed her with hepatic myelopathy, which is a rare complication of liver cirrhosis and portosystemic venous shunts. Hepatic myelopathy resulting from a congenital IPSVS has not been previously reported. A diagnosis of hepatic myelopathy should be ruled out in diagnostically difficult cases of paraparesis.