Hepatic encepahalopathy

Hepatic encepahalopathy is a neuropsychiatric syndrome with multiple manifestations. It is caused by liver failure and / or portosystemic shunting of blood. It is potentially reversible.

Loss of function / or mass of hepatocytes can cause hepatic encephalopathy. The former occurs in acute fatty liver of pregnancy.

Pathogenesis of hepatic encephalopathy

Various agents are implicated in the pathogenesis of hepatic encephalopathy:

Direct ammonia toxicity

Mercaptan, short chain fatty acids

Aromatic amino acids

GABA

Types of hepatic encephalopathy

1. Acute liver failure

2. Major portosystemic shunt without cirrhosis as in non-cirrhotic portal hypertension

3. Chronic liver disease

Overt vs minimal hepatic encephalopathy

Overt hepatic encephalopathy: Altered consciousness, asterixis, hyper-reflexia, rigidity, altered sleep rhythm, fetor hepaticus

Minimal hepatic encephalopathy:  It is not obvious and is detected only by tests like number connection tests or neuro imaging. It is important to be checked in pilots, drivers etc with chronic liver disease as it can affect critical decesion making with catastrophic results.

Precipitating factors for hepatic encephalopathy

Gastro-intestinal hemorrhage, sepsis, electrolyte imbalance, sedatives, alcoholic binge, hepatocellular carcinoma

It is important to exclude other causes of encephalopathy and serum ammonia level estimation may help in excluding a diagnosis of hepatic encephalopathy in such situations.

Empiric treatment of hepatic encephalopathy

Gut cleansing with bowel wash etc.

Low protein diet

Lactulose / Lactitol

Bowel sterilization with neomycin / metronidazole

Probiotics may have a role

In acute liver failure, there is deeper coma, cerebral edema and a worse outcome.

Liver transplantation is probably the only final answer.