Late presentation of fatal hyperammonemic encephalopathy after Roux-en-Y gastric bypass.

Worldwide, there have been <25 reported cases of hyperammonemic encephalopathy associated with Roux-en-Y gastric bypass surgery in the absence of cirrhosis. We describe a 42-year-old woman who presented with subacute but progressive neurological decline late in her postoperative course, which deteriorated despite multiple conservative and aggressive measures, including hemodialysis, in an attempt to reduce measured plasma ammonia levels. This syndrome of hyperammonemic encephalopathy represents a serious, underrecognized, and potentially treatable complication after Roux-en-Y gastric bypass.