COMMENTARY

Hepatic Encephalopathy and Driving

David A. Johnson, MD

Disclosures

April 11, 2011

Evidence of Persistent Cognitive Impairment After Resolution of Overt Hepatic Encephalopathy

Riggio O, Ridola L, Pasquale C, et al
Clin Gastroenterol Hepatol. 2011;9:181-183

Abstract

Legal Ramifications for Physicians of Patients Who Drive With Hepatic Encephalopathy

Cohen SM, Kim A, Metropulos M, Ahn J
Clin Gastroenterol Hepatol. 2011;9:156-160

Abstract

Background

Hepatic encephalopathy (HE) is a well-recognized complication of cirrhosis. Because the spectrum of HE ranges from overt to subclinical, the true prevalence of this condition is not well defined but is estimated to involve up to 60% of patients with cirrhosis. It has been recently reported that even a single episode of HE is associated with a persistent cognitive defect, suggesting that HE is not a truly reversible condition.

Although the clinical picture of overt HE is readily apparent, minimal HE (MHE) may be much less obvious. The term MHE refers to alterations of cognitive function, despite a relatively normal clinical appearance and examination. Whereas overt HE can be demonstrated with a mental status exam, MHE requires complex psychometric testing of specific cognitive functions, including inhibition, attention, and working memory. Such testing is not widely available and certainly not used in routine clinical practice. MHE has been associated with reductions in patient quality of life, and recently with an increased number of motor vehicle violations and auto accidents. Further complicating this association is the apparent poor insight that these patients have into their compromised driving skills.

Study Summaries

Riggio and coworkers evaluated 106 patients with cirrhosis (27 with previous HE, 34 MHE, 45 normal) using psychometric testing. Patients were examined twice within 3 days. For the patients without previous overt HE, the psychometric testing results demonstrated improvement in performance. In contrast, the patients with an earlier episode of overt HE showed a lack of learning capacity and persistent deficits, suggesting that HE was not a fully reversible condition.

Cohen and colleagues compiled an evaluation of the legal ramifications for healthcare providers of HE patients who drive. The investigators contacted the Divisions of Motor Vehicles for each of the 50 states in the United States and searched for HE-related lawsuits. Only 6 states (12%) had laws for mandatory reporting of these patients. In 25 of the remaining 44 states (57%), legal immunity was provided to healthcare providers who reported these patients although the reporting was not mandatory. Of interest, the definition of "impaired driver" varied considerably and no state specifically mentioned HE or cirrhosis as a reportable condition. None of the database analyses revealed any legal cases against healthcare providers for failure to warn patients with HE against driving. Furthermore, no lawsuits in which HE was identified as a causal condition for a motor vehicle accident were found.

Viewpoint

An editorial by Bajaj and associates that accompanies the legal ramifications study is a provocative discussion focusing on the extended liability of driving with HE or MHE. Although a proof of concept study by Bajaj has previously demonstrated improvement of driving simulator performance after treatment of MHE with rifaximin, the testing to define MHE is neither standardized nor available for routine clinical use. Bajaj suggests that because healthcare providers are not trained in evaluations for driving fitness, nor are they officers of the state agencies charged to enforce these rules, they should follow the applicable local laws. Impaired driving poses a significant risk both to patients and other drivers, so it is critical to discuss and evaluate the potential for HE or MHE-related driving impairment with the patient and family members. One subtle indicator of a driving problem for patients with MHE is an impairment of navigation skills. A focused discussion (with both the patient and family members who may ride with the patient) should query about compromised acuity with respect to navigation skills.

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