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Minimal hepatic encephalopathy

Nature Clinical Practice Gastroenterology & Hepatology volume 4, pages 677–685 (2007)Cite this article

Abstract

Minimal hepatic encephalopathy (MHE), formerly known as subclinical hepatic encephalopathy, is the mild cognitive impairment commonly seen in patients who have cirrhosis. Current understanding suggests that MHE forms part of the spectrum of hepatic encephalopathy, although this remains to be proven. Although traditionally viewed as having negligible clinical significance, MHE has a significant impact on quality of life. MHE often goes undiagnosed because in many patients there is no evidence of clinically overt signs of impaired cognition. In addition, the diagnostic criteria for MHE have not been standardized, which means that the exact characteristics of MHE remain in question. This Review focuses on the pathogenesis and neuropsychological findings (incorporating neuroimaging) of MHE, as well as the effect of MHE on quality of life and survival, and developments in treatment.

Key Points

  • Minimal hepatic encephalopathy (MHE), formerly known as subclinical hepatic encephalopathy, is the mild cognitive impairment commonly seen in patients who have cirrhosis

  • MHE is currently considered to be one end of the clinical spectrum of hepatic encephalopathy (a complex neuropsychiatric disorder), rather than a separate phenomenon; although the pathophysiology of hepatic encephalopathy is still being elucidated, it is known to be linked to hyperammonemia, impaired neurotransmission and cerebral metabolism

  • MHE can have adverse effects on quality of life (e.g. performance in the workplace and driving) and survival, but remains undiagnosed in many patients because they have no clinically overt signs of impaired cognition

  • The diagnostic criteria for MHE have not been standardized but rest on the patient's history, a careful physical examination, the exclusion of other neurological disorders, and the performance of neuropsychological and neurophysiological tests

  • The most established treatment for hepatic encephalopathy is lactulose, but its efficacy has never been evaluated in a placebo-controlled randomized fashion; preliminary data suggest that the use of antioxidants or antibiotics as a potential treatment for MHE warrants further study

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Figure 1: Suggested algorithm for assessing minimal hepatic encephalopathy in patients with cirrhosis.

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Acknowledgements

CAS has received financial support from the NIH (grant K23DK60018) and the Fiterman Foundation, Mayo Clinic.

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  1. CA Stewart is an Assistant Professor of Medicine in the Division of Gastroenterology and Hepatology, and GE Smith is a Professor of Psychology in the Department of Tertiary Psychiatry and Psychology, Mayo Clinic, Rochester, MN, USA.,

    Charmaine A Stewart & Glenn E Smith

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Correspondence to Charmaine A Stewart.

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Stewart, C., Smith, G. Minimal hepatic encephalopathy. Nat Rev Gastroenterol Hepatol 4, 677–685 (2007). https://doi.org/10.1038/ncpgasthep0999

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