Gastric-bypass associated hyperammonaemia (GaBHA) is an under-recognised cause of non-hepatic encephalopathy that is associated with significant mortality and has limited reporting in published literature.
GaBHA has been reported predominately in middle-aged females with a past surgical history of Roux-En-Y surgical procedure. Individuals may present at any stage post-surgery and an important minority may have an undiagnosed inherited metabolic disorder.
We report a case of a 49 year old woman who presented acutely with encephalopathy, a significantly elevated plasma ammonia level, and substantial multifactorial nutritional deficiency which required correction with intensive enteral and parenteral nutritional support. This case represented a diagnostic and management challenge for acute medical physicians and the multidisciplinary team involved.

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