Nonhepatic hyperammonemic encephalopathy complications following bariatric surgery: a case report and review of the literature

J Med Case Rep. 2021 Jul 20;15(1):385. doi: 10.1186/s13256-021-02922-2.


Background: Hyperammonemic encephalopathy, a rare but fatal condition, is increasingly being reported as a possible complication of bariatric surgery. Here, we present a case of hyperammonemic encephalopathy, focusing on the clinical presentation, diagnostic measures, and our treatment methods, which resulted in a rare favorable outcome, emphasizing the unique role of renal replacement treatment. We also provide a detailed discussion of the mechanism through which hyperammonemia occurs secondarily to bariatric surgery.

Case presentation: A 44-year-old Moroccan Jew woman with a history of obesity presented in the hospital with urea cycle disorder that manifested after bariatric surgery. A rapid diagnostic process, together with conservative treatment with lactulose, nutritional supplementation, dietary protein restriction, and ammonia scavengers did not result in adequate improvement. Therefore, hemofiltration was performed, which yielded a favorable outcome.

Conclusions: The case findings indicate an association between hyperammonemic encephalopathy and bariatric surgery, and support early treatment with ammonia scavengers, as currently accepted. Nevertheless, if rapid improvement is not seen, it is advisable to consider hemodialysis or hemofiltration as early invasive strategies.

Keywords: Bariatric surgery; Encephalopathy; Hyperammonemia; Urea cycle disorder.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Adult
  • Ammonia
  • Bariatric Surgery* / adverse effects
  • Female
  • Humans
  • Hyperammonemia* / etiology
  • Hyperammonemia* / therapy
  • Obesity
  • Urea Cycle Disorders, Inborn*


  • Ammonia