hepatic encephalopathy (HE)

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Hepatic encephalopathy (HE) is a metabolic disorder of the central nervous system and neuromuscular system that occurs in decompensated cirrhosis.

The American Association for the Study of Liver Diseases/European Association for the Study of the Liver (AASLD/EASL) guidelines defines HE as:

“a brain dysfunction caused by liver insufficiency and/or portosystemic shunting (PSS); it manifests as a wide spectrum of neurological or psychiatric abnormalities ranging from subclinical alterations to coma” (1).

HE can be divided into 2 broad categories based on severity:

covert hepatic encephalopathy (CHE)

also known as minimal hepatic encephalopathy (MHE)
is a subclinical and less severe form of HE
patients may have subtle neuropsychological problems, psychomotor slowing, and difficulty with activities of daily living e.g. – employment and driving problems
requires the use of psychometric testing to make a diagnosis
has a poor prognosis and is associated with increased risk of hospitalisation and progression to overt hepatic encephalopathy or death

overt hepatic encephalopathy (OHE)

pathognomonic feature of liver failure and defines the decompensated phase of the disease,
associated with increased rates of hospitalizations and mortality, and poor quality of life
is also reported in patients without cirrhosis with extensive PSS (1,2,3).

The features of HE depend on the aetiology and precipitating factors, eventually developing into stupor and then coma.

some aetiologies of the hepatic failure, for example paracetamol overdose, can precipitate this condition within three or four days, with a very rapid progression through the grades of encephalopathy
other aetiologies, for example viral hepatitis, are associated with a much more variable onset.

Patients who are diagnosed with hepatic encephalopathy should stop driving and inform the Driver and Vehicle Licensing Authority (DVLA) (2).

Reference:

Last reviewed 01/2018

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