BACKGROUND: The subtype of hepatic encephalopathy (HE) called minimal hepatic encephalopathy (MHE) is highly prevalent (22-74%) among patients with liver dysfunction. MEH is defined as HE without grossly evident neurologic abnormalities, but with cognitive deficits that can be revealed by psychometric testing.
METHODS: This article is based on relevant original publications and reviews in English and German (1970-2011) that were retrieved by a selective key-word-based search in the Medline and PubMed databases.
RESULTS: Despite its mild manifestations, MHE impairs patients' quality of life and their ability to work. It impairs driving ability and is associated with a higher rate of motor vehicle accidents. Furthermore, patients with MHE fall more often and are more likely to undergo progression to overt HE. The main pathophysiological mechanism of MHE is hyperammonemia leading to astrocyte dysfunction. Psychometric tests are the standard instruments for establishing the diagnosis; further, supportive diagnostic tools include neurophysiological tests and imaging studies. Recent randomized and controlled trials have revealed that treatment with lactulose or rifaximin therapy improves the quality of life of patients with MHE. Rifaximin was also found to improve driving performance in a simulator. A combination of these two drugs prevents the recurrence of episodic HE over a 6-months follow-up period. Moreover, small-scale trials have revealed that some dietary supplements can improve the cognitive deficits of MHE.
CONCLUSION: Clinical trials have shown that patients with MHE and patients who have had an episode of overt HE in the past can benefit from drug treatment.