What are the grades of encephalopathy and their corresponding clinical presentations?

Grading of Hepatic Encephalopathy

Hepatic encephalopathy is graded using the West Haven Criteria (Grades 0-IV), with modern classification dividing patients into covert HE (minimal HE plus Grade I) and overt HE (Grades II-IV), based on the presence of clinically apparent disorientation and asterixis. 1

West Haven Grading System

The West Haven Criteria remain the gold standard for grading hepatic encephalopathy severity, despite significant inter-rater variability, particularly between Grades 0, minimal, and I 1, 2, 3:

Grade 0 (Unimpaired)

• No clinical, neuropsychometric, or neurophysiological abnormalities 1
• Normal cognitive function on all testing modalities 1

Minimal Hepatic Encephalopathy

• No clinically apparent symptoms during routine examination 4
• Abnormalities detected only through formal neuropsychological testing or neurophysiological assessment 1, 3
• Affects up to 80% of cirrhotic patients 4
• Impairments include decreased attention, poor memory, and impaired psychomotor performance 4

Grade I

• Subtle changes in behavior, mild confusion, or sleep disturbance 1
• No disorientation or asterixis present 1
• Extremely high inter-observer variability in identification 1

Grade II

• Lethargy or apathy 1
• Disorientation to time is the key differentiator from Grade I 1
• Asterixis may be present 1
• Good inter-rater reproducibility when using operative definitions emphasizing disorientation 1
• Requires therapeutic intervention 1

Grade III

• Somnolence to semi-stupor 1
• Responsive to verbal stimuli 1
• Confusion and gross disorientation 1

Grade IV

• Coma 1
• Unresponsive to verbal or noxious stimuli 1

Modern Classification Framework

The International Society for Hepatic Encephalopathy and Nitrogen Metabolism (ISHEN) recommends a simplified two-category system 1, 5:

Covert Hepatic Encephalopathy

• Encompasses minimal HE plus Grade I West Haven criteria 1, 4, 5
• Defined by absence of disorientation AND absence of asterixis 1
• Patients appear clinically normal but demonstrate neuropsychometric/neurophysiological abnormalities 1, 5
• Generally not treated in clinical practice, allowing placebo-controlled trials 1

Overt Hepatic Encephalopathy

• Encompasses West Haven Grade II or higher 1, 4, 5
• Characterized by evident clinical abnormalities with changes in mental status 5
• Requires medical intervention and possible hospitalization 1

SONIC Classification (Spectrum of Neuro-cognitive Impairment in Cirrhosis)

This continuous approach provides additional prognostic stratification 1:

Stable Impairment

• Covert or overt HE with minimal day-to-day fluctuation 1
• Majority remain independent in daily activities 1

Unstable Impairment (Episodic HE)

• Previously stable patients who develop acute deterioration over hours to days 1
• Progress from acute confusional syndrome to coma 1
• Require medical attention and hospitalization 1

Critical Clinical Pitfalls

Asterixis presence automatically excludes covert HE classification - patients with flapping tremor, even without disorientation, should be classified as having overt HE 1, 2.

The distinction between minimal and Grade I HE is unreliable - this is why they are grouped together as covert HE in modern practice 1.

Disorientation to time is the most reproducible clinical marker - use this as the primary differentiator between covert and overt HE rather than subjective behavioral changes 1.

Not all cognitive complaints in cirrhotic patients are HE - differential diagnosis must include alcohol-related cognitive dysfunction, thiamine deficiency, HCV-related impairment, and age-related decline 4.