Hyperammonemic syndrome after Roux‐en‐Y gastric bypass

Abstract

Objective: Hyperammonemic encephalopathy is an uncommon but severe complication of the Roux-en-Y gastric bypass surgery for obesity. Mechanisms underlying this complication are incompletely understood, resulting in delayed recognition and management. This study evaluated common laboratory findings and possible etiology of hyperammonemic encephalopathy after successful Roux-en-Y gastric bypass surgery. Methods: A retrospective review of 20 patients identified through our own clinical practice was conducted, with the addition of similar cases from other institutions identified through the review of literature. Results: Patients presenting with hyperammonemic encephalopathy after Roux-en-Y gastric bypass surgery presented with overlapping clinical and laboratory findings. Common features included: (1) weight loss following successful Roux-en-Y gastric bypass for obesity; (2) hyperammonemic encephalopathy accompanied by elevated plasma glutamine levels; (3) absence of cirrhosis; (4) hypoalbuminemia; and (5) low plasma zinc levels. The mortality rate was 50%. Ninety-five percent of patients were women. Three patients were diagnosed with proximal urea cycle disorders. One patient experienced improvement in the hyperammonemia after surgical correction of spontaneous splenorenal shunt. Conclusions: Hyperammonemic encephalopathy after Roux-en-Y gastric bypass surgery is a newly recognized, potentially fatal syndrome with diverse pathophysiologic mechanisms encompassing genetic and nongenetic causes.

Hyperammonemic encephalopathy in a pediatric patient with Salmonella enteritis and after Roux‐en‐Y surgery

“…this interval was reminiscent of that in a previous study in which the interval ranged from 1 month to 28 years. 2 However, in our case, Roux-en-Y hepaticojejunostomy was different from adult Roux-en-Y gastric bypass. Another interesting finding in this case was the Salmonella colitis, which has been associated with enteric hyperammonemia in equines in a previous study.…”

Noncirrhotic hyperammonemia after deceased donor kidney transplantation: A case report

“…Adult‐onset noncirrhotic hyperammonemia (NCH) is a rare clinical condition that is distinct from hepatic encephalopathy. The condition is associated with a very high morbidity and mortality and has been described in a variety of settings, including post–solid organ transplantations, most commonly post–lung transplantion, but rarely in post–heart or post–kidney transplantation . Four prior case reports exist for post–kidney transplantation NCH, 3 of which were associated with patient mortality.…”

Late Presentation of Fatal Hyperammonemic Encephalopathy After Roux-En-Y Gastric Bypass

“…Rigorous screening for select metabolic derangements (e.g., plasma ammonia, zinc, and serum albumin) in high-risk patients may facilitate early detection of this clinical entity. Genetic screening for OTC defi ciency may also be considered, although this approach has not been fruitful in reported patients ( 3 ). Evaluating for in vivo OTC enzymatic activity in fresh liver tissue is of particular interest, but this requires a liver biopsy.…”