What are the diagnostic criteria for Hepatic (Liver) Encephalopathy?

From the Guidelines

The diagnosis of Hepatic Encephalopathy (HE) should be based on the West Haven criteria for grading, with the addition of the Glasgow coma scale for patients with grades III-IV, and neuropsychological/neurophysiological or therapeutic tests for those with no or mild neuropsychiatric abnormalities. The West Haven criteria is a widely accepted and easy-to-use scale for grading the severity of HE, ranging from grade 0 (minimal changes detectable only by specialized testing) to grade 4 (coma) 1. According to the EASL clinical practice guidelines, the West Haven criteria should be used for HE grading when at least temporal disorientation is present (i.e., from West Haven grades >2) 1.

Some key points to consider in the diagnosis of HE include:

• The use of neuropsychological/neurophysiological or therapeutic tests to diagnose covert HE in patients with no or mild neuropsychiatric abnormalities 1
• The addition of the Glasgow coma scale for patients with grades III-IV West Haven criteria, especially in those with impaired consciousness, including those managed in an intensive care unit 1
• The importance of excluding other causes of brain dysfunction and identifying precipitating factors, such as GI bleeding, infection, electrolyte disturbances, constipation, or medication non-compliance
• The use of laboratory findings, such as elevated serum ammonia levels, and diagnostic tests, including the Number Connection Test, digit symbol test, and critical flicker frequency test for minimal hepatic encephalopathy, to support the diagnosis

It is essential to note that the diagnosis of overt HE is usually straightforward in clinical practice, but grading and staging are mandatory, mainly for monitoring 1. The West Haven scale is easy to use in clinical practice, at least from grade II upwards, and its semi-quantitative equivalents can help standardize the grading process 1.

From the FDA Drug Label

A breakthrough overt HE episode was defined as a marked deterioration in neurological function and an increase of Conn score to Grade ≥2. In patients with a baseline Conn score of 0, a breakthrough overt HE episode was defined as an increase in Conn score of 1 and asterixis grade of 1

The diagnostic criteria for Hepatic (Liver) Encephalopathy mentioned in the label are:

• A marked deterioration in neurological function
• An increase of Conn score to Grade ≥2
• For patients with a baseline Conn score of 0, an increase in Conn score of 1 and asterixis grade of 1 2

From the Research

Diagnostic Criteria for Hepatic Encephalopathy

The diagnostic criteria for Hepatic Encephalopathy (HE) can be summarized as follows:

• HE is a neuropsychiatric syndrome that can develop in the course of chronic and acute liver disease, characterized by cognitive and motoric deficits of varying severity 3
• The diagnosis of manifest HE is based on clinical symptoms according to the West Haven criteria 3, 4
• The diagnosis of minimal HE requires psychometric or neurophysiological testings, such as critical flicker frequency or evoked potentials 3, 5
• Neuropsychological tests are sensitive and objective in diagnosing HE, especially for the detection of minimal HE 6, 7
• Biochemical diagnostic tests, such as ammonia level, can be used to confirm or exclude the diagnosis and to monitor the effect of treatment 7

Classification of Hepatic Encephalopathy

HE can be classified into different grades of severity, ranging from:

• Grade 0: normal mental status
• Grade 1: minimal alterations of neurocognitive functions
• Grade 2: confusion and disorientation
• Grade 3: poor coordination and asterixis
• Grade 4: coma 4, 7

Diagnostic Methods

Various diagnostic methods are available for HE, including:

• Clinical criteria, such as the West Haven criteria 3, 4
• Psychometric tests, such as the psychometric hepatic encephalopathy score 4
• Neurophysiological tests, such as visually evoked potentials (P300 wave) and critical flicker frequency analysis 5
• Biochemical tests, such as ammonia level 7
• Brain imaging, such as magnetic resonance spectroscopy or positron emission tomography 7