A patient with hemodialysis-related hyperammonemic encephalopathy: a delayed presentation of congenital arterioportal fistulas.

We present a 32-year-old woman who developed hyperammonemic encephalopathy during hemodialysis. She was rather well before 2009 when receiving peritoneal dialysis due to chronic interstitial nephritis. Due to a refractory peritonitis, the treatment was shifted to hemodialysis in January 2009. About 1 year later, she was found with consciousness disturbance during hemodialysis then admitted to the hospital because of hyperammonemia (165 μg/dl). During hospitalization, the patient's abdominal Doppler sonography showed a hepatofugal flow in the portal trunk while the hepatic artery angiography demonstrated multiple intrahepatic arterioportal fistulas. Her general condition was improved after the treatment of lactulose and hepatic artery embolization. With the occurrence of arterioportal fistulas induced portal hypertension, we speculated that the portal-systemic shunt was enhanced during hemodialysis because of venous hypotension which then resulted in the transient hyperammonemia. To the best of our knowledge, this is the first patient who developed hemodialysis- related hyperammonemic encephalopathy due to multiple arterioportal fistulas.