Development of a clinical hepatic encephalopathy staging scale

A simplified psychometric evaluation for the diagnosis of minimal hepatic encephalopathy

BACKGROUND & AIMS

The psychometric hepatic encephalopathy score (PHES), which includes 5 psychometric tests, is a standard for the diagnosis of minimal hepatic encephalopathy (HE). We investigated whether a simplified PHES (SPHES) is as useful as the whole PHES.

METHODS

The PHES was determined for 79 cirrhotic patients (the training group), who were followed up for the development of overt HE. Backward logistic regression was performed by eliminating stepwise variables--removal did not impair regression. A separate series of 65 patients was used as a validation group.

RESULTS

The PHES was abnormal in 45 patients. The SPHES, determined from the digit symbol, serial dotting, and line tracing tests, did not differ significantly from the full PHES; 24 of the 79 patients developed overt HE. The likelihood of developing overt HE was higher among patients with an abnormal PHES (log-rank P = .003) or SPHES (P = .004). By using Cox regression and model for end-stage liver disease scores to analyze data from patients with previous HE and transjugular intrahepatic portosystemic shunts, PHES (relative risk, 4.16; P = .003) and SPHES (relative risk, 3.70; P = .004) were the only variables associated with the development of overt HE. The accuracy of the SPHES was confirmed in the validation group.

CONCLUSIONS

A simplified PHES is as good as the PHES in diagnosing minimal HE and in predicting the occurrence of overt HE.

New assessment of hepatic encephalopathy

Hepatic encephalopathy (HE) is a common complication of cirrhosis that requires careful appraisal of the clinical manifestations, evaluation of the underlying neurological disorders, and assessment of liver function and the portal-systemic circulation. This article reviews recent developments in the assessment of HE and discusses the controversy regarding the use of a categorical or a continuous approach in measuring the severity of this condition. New scales facilitate effective monitoring and assessment of episodic HE. Neuropsychological test batteries and neurophysiological tests are of value for evaluating cognitive function in outpatients and can establish the diagnosis of minimal HE, and the severity of low-grade HE. These tools allow better evaluation of the origin of cognitive complaints and help in estimating the risk of accidents. It is now possible to complete the evaluation with measurement of the effects of cognitive impairment on daily living. In difficult cases, imaging of the brain and portal-systemic circulation with magnetic resonance imaging is especially helpful. Based on these studies, neurological signs and symptoms can be attributed to HE in patients with mild liver disease and in those with complex neurological manifestations. The new methods presented are also valuable for investigating the neurological manifestations occurring after liver transplantation.

Review article: the modern management of hepatic encephalopathy

BACKGROUND; Hepatic encephalopathy, both overt and minimal, forms a continuum of cognitive change in cirrhosis. Strategies to diagnose and treat hepatic encephalopathy have evolved considerably.

AIM

To examine the updated diagnostic and treatment strategies for hepatic encephalopathy.

METHODS

Techniques for the clinical, psychometric and neurophysiological evaluation of hepatic encephalopathy are reviewed. The methods reviewed include pure clinical scales (West-Haven), psychometric tests (PSE-syndrome test), neurophysiological tests (EEG, Critical flicker frequency, CFF) and computerized tests (Inhibitory control test, ICT).

RESULTS

Clinical scales are limited, whereas psychometric tests (specifically PSE-syndrome test), CFF and ICT can be used to diagnose minimal hepatic encephalopathy. However, there is no single test that can capture the entire spectrum of cognitive impairment. Treatment options and goals depend on the acuity of hepatic encephalopathy. In-patient management should concentrate on supportive care, precipitating factor reversal and lactulose and/or rifaximin therapy. Out-patient therapy should aim to prevent recurrences, and both lactulose and rifaximin have evidence to support their use.

CONCLUSIONS

Diagnostic techniques for hepatic encephalopathy range from simple scales to sophisticated tools. Treatment options depend on the stage of hepatic encephalopathy. The future challenge is to evaluate cognitive function as a continuum with clinically relevant outcomes and to develop well-tolerated and inexpensive treatments for hepatic encephalopathy.

Minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) is the mildest form of spectrum of hepatic encephalopathy (HE). Patients with MHE have no recognizable clinical symptoms of HE but have mild cognitive and psychomotor deficits. The prevalence of MHE is high in patients with cirrhosis of liver and varies between 30% and 84%; it is higher in patients with poor liver function. The diagnostic criteria for MHE have not been standardized but rest on careful patient history and physical examination, normal mental status examination, demonstration of abnormalities in cognition and/or neurophysiological function, and exclusion of concomitant neurological disorders. MHE is associated with impaired health-related quality of life, predicts the development of overt HE and is associated with poor survival. Hence, screening all patients with cirrhosis for MHE using psychometric tests, and treatment of those patients diagnosed to have MHE has been recommended. Ammonia plays a key role in the pathogenesis of MHE, which is thought to be similar to that of overt HE. Thus, ammonia-lowering agents such as lactulose and probiotics have been tried. These agents have been shown to improve cognitive and psychometric deficits, and have good safety profile. Future studies will better define the role of other drugs, such as rifaximin, acetyl L-carnitine and L-ornithine L-aspartate.

Management options for minimal hepatic encephalopathy

Minimal hepatic encephalopathy (MHE) is a neurocognitive dysfunction that is present in the majority of patients with cirrhosis. MHE has a characteristic cognitive profile that cannot be diagnosed clinically. This cognitive dysfunction is independent of sleep dysfunction or problems with overall intelligence. MHE has a significant impact on quality of life, the ability to function in daily life and progression to overt hepatic encephalopathy. Driving ability can be impaired in MHE and this may be a significant factor behind motor vehicle accidents. A crucial aspect of the clinical care of MHE patients is their driving history, which is often ignored during routine care and can add a vital dimension to the overall disease assessment. Driving history should be an integral part of the care of patients with MHE. The preserved communication skills and lack of specific signs and insight make MHE difficult to diagnose. The predominant strategies for MHE diagnosis are psychometric or neurophysiological testing. These are usually limited by financial, normative or time constraints. Studies into inhibitory control, cognitive drug research and critical flicker frequency tests are encouraging. These tests do not require a psychologist for administration and interpretation. Lactulose and probiotics have been studied for their potential use as therapies for MHE, but these are not standard-of-care practices at this time. Therapy can improve the quality of life in MHE patients but the natural history, specific diagnostic strategies and treatment options are still being investigated.

Hepatic encephalopathy

Hepatic encephalopathy (HE) is a syndrome of neuropsychiatric dysfunction caused by portosystemic venous shunting, with or without intrinsic liver disease. Patients with hepatic encephalopathy often present with the onset of mental status changes ranging from subtle psychologic abnormalities to profound coma. Several hypotheses have been proposed to explain the mental impairment associated with portosystemic shunting and liver disease. Clinicians diagnosing HE frequently have the opportunity to intervene and reverse severe HE, even hepatic coma. The recent advances in understanding and management of HE are the subject of this article.