Criteria
Guidelines representing the position of both the American Association for the Study of Liver Diseases and the European Association for the Study of the Liver outline a four-factor classification system for HE:[1][2]
1) Underlying disease
Type A: HE associated with acute liver failure
Type B: HE associated predominantly with portosystemic bypass or shunting
Type C: HE associated with cirrhosis
2) Grade of HE manifestations and clinical description (West Haven criteria)
Unimpaired: no presence of HE, no history of HE
Minimal (covert): psychometric or neuropsychological alterations of tests exploring psychomotor speed/executive functions or neurophysiological alterations without clinical evidence of mental change
Grade 1 (covert): trivial lack of awareness, sleep rhythm alterations, shortened attention span, impaired addition or subtraction, euphoria or anxiety
Grade 2 (overt): lethargy or apathy, disorientation for time, obvious personality change, inappropriate behaviour, dyspraxia, asterixis
Grade 3 (overt): somnolence to semi-stupor, responsive to stimuli, confused, gross disorientation, bizarre behaviour
Grade 4 (overt): coma
3) Time
Episodic HE
Recurrent HE (≥2 episodes within 6 months)
Persistent HE (behavioural alterations that are always present and are interspersed with episodes of overt HE)
4) Existence of precipitating factors; HE is either:
Non-precipitated
Precipitated (can be identified in nearly all bouts of episodic HE type C)
For discussion on the management of type A hepatic encephalopathy, see our topic Acute liver failure.
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