Hostname: page-component-586b7cd67f-rdxmf Total loading time: 0 Render date: 2024-11-24T12:45:24.501Z Has data issue: false hasContentIssue false
  • English
  • Français

Myth: Interpretation of a single ammonia level in patients with chronic liver disease can confirm or rule out hepatic encephalopathy

Published online by Cambridge University Press:  21 May 2015

Sanjay Arora ,
Christopher L. Martin  and
Mel Herbert
Sanjay Arora*
Affiliation:
Keck School of Medicine
Christopher L. Martin
Affiliation:
Keck School of Medicine, LAC+USC Department of Emergency Medicine, Los Angeles, Calif
Mel Herbert
Affiliation:
Keck School of Medicine, LAC+USC Department of Emergency Medicine, Los Angeles, Calif
*
Department of Emergency Medicine, Los Angeles County-USC Healthcare Network, 1200 N State St., Los Angeles CA 90033

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Although the exact pathophysiology of hepatic encephalopathy (HE) is not fully understood, for more than a century ammonia has been thought to play a critical role. However, the interpretation and utility of ammonia levels in patients with chronic liver disease (CLD) presenting with HE has been a long-standing source of confusion. It is a common belief in the emergency department and on the wards that a single elevated ammonia level in a patient with CLD can confirm the diagnosis of HE, and a normal level essentially rules it out. This confusion stems from the fact that early studies showed a correlation between degree of encephalopathy and the ammonia level, but numerous subsequent studies have shown that severely encephalopathic patients often have normal ammonia levels. This paper reviews the published literature on ammonia levels in patients with CLD in an attempt to clarify its value as a clinical decision-making tool in patients with suspected HE.

Keywords

ammonia levelschronic liver diseasehepatic encephalopathy
Type
Education • Éducation
Information
Canadian Journal of Emergency Medicine , Volume 8 , Issue 6 , November 2006 , pp. 433 - 435
Copyright
Copyright © Canadian Association of Emergency Physicians 2006

References

1.Butterworth, RF. Complications of cirrhosis. J Hepatol 2000;32:71–80.Google Scholar
2.Stahl, J. Sutdies of blood ammonia in liver disease. Ann Intern Med 1963;58:1–24.CrossRefGoogle Scholar
3.Ong, JP, Aggarwal, A, Krieger, D, et al. Correlation between ammonia levels and the severity of hepatic encephalopathy. Am J Med 2003;114:188–93.CrossRefGoogle ScholarPubMed
4.Nicolao, F, Efrati, C, Masini, A, et al. Role of determination of partial pressure of ammonia in cirrhotic patients with and without hepatic encephalopathy. J Hepatol 2003;38:441–6.Google Scholar
5.Kundra, A, Jain, A, Banga, A, et al. Evaluation of plasma ammonia levels in patients with acute liver failure and chronic liver disease and its correlation with the severity of hepatic encephalopathy and clinical features of raised intracranial tension. Clin Biochem 2005;38:696–9.Google Scholar
6.Lockwood, AH. Blood ammonia levels and hepatic encephalopathy. Metab Brain Dis 2004;19:345–9.CrossRefGoogle ScholarPubMed
7.Wang, V, Saab, S. Ammonia levels and the severity of hepatic encephalopathy. Am J Med 2003;114:237–8.Google Scholar