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Case Reports in Medicine
Volume 2016, Article ID 8512721, 10 pages
Case Report

Hyperammonemia: What Urea-lly Need to Know: Case Report of Severe Noncirrhotic Hyperammonemic Encephalopathy and Review of the Literature

1Department of Neurological Sciences, Rush University Medical Center, 1725 West Harrison Street, POB Suite 1121, Chicago, IL 60612, USA
2Rush Medical College, Rush University Medical Center, 600 S. Paulina Street, Chicago, IL 60612, USA
3Department of Neurology, Division of Neurocritical Care, University of Florida, McKnight Brain Institute, Room L3-100, 1149 Newell Drive, Gainesville, FL 32611, USA

Received 13 July 2016; Accepted 28 August 2016

Academic Editor: Piotr K. Janicki

Copyright © 2016 Ruby Upadhyay et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Purpose. A 66-year-old man who presented with coma was found to have isolated severe hyperammonemia and diagnosed with a late-onset urea-cycle disorder. He was treated successfully and had full recovery. Methods. We report a novel case of noncirrhotic hyperammonemia and review the literature on this topic. Selected literature for review included English-language articles concerning hyperammonemia using the search terms “hyperammonemic encephalopathy”, “non-cirrhotic encephalopathy”, “hepatic encephalopathy”, “urea-cycle disorders”, “ornithine transcarbamylase (OTC) deficiency”, and “fulminant hepatic failure”. Results. A unique case of isolated hyperammonemia diagnosed as late-onset OTC deficiency is presented. Existing evidence about hyperammonemia is organized to address pathophysiology, clinical presentation, diagnosis, and treatment. The case report is discussed in context of the reviewed literature. Conclusion. Late-onset OTC deficiency presenting with severe hyperammonemic encephalopathy and extensive imaging correlate can be fully reversible if recognized promptly and treated aggressively.