Hepatic encephalopathy

Hepatic encephalopathy may be seen in liver disease of any cause. The aetiology is not fully understood but is thought to include excess absorption of ammonia and glutamine from bacterial breakdown of proteins in the gut.

Whilst hepatic encephalopathy is often associated with acute liver failure it may also be seen with chronic disease. It is now recognised that many patients with liver cirrhosis may develop subtle symptoms such as mild cognitive impairment before the features become more recognisable ('minimal' or 'covert' hepatic encephalopathy). It has also been noted that transjugular intrahepatic portosystemic shunting (TIPSS) may precipitate encephalopathy.

Features

• confusion, altered GCS (see below)
• asterix: 'liver flap', arrhythmic negative myoclonus with a frequency of 3-5 Hz
• constructional apraxia: inability to draw a 5-pointed star
• triphasic slow waves on EEG
• raised ammonia level (not commonly measured anymore)

Grading of hepatic encephalopathy

• Grade I: Irritability
• Grade II: Confusion, inappropriate behaviour
• Grade III: Incoherent, restless
• Grade IV: Coma

Precipitating factors PINCH GRD

• infection e.g. spontaneous bacterial peritonitis
• GI bleed
• post transjugular intrahepatic portosystemic shunt
• constipation
• drugs: sedatives, diuretics