What is the pathophysiology of hepatic encephalopathy?

This manifestation : Of liver disease occurs when the detoxifying function of the liver is compromised usually by chronic liver disease of one sort or another. We measure ammonia levels in the blood as a marker for this dysfunction but other nitrogen containing substances are more responsible.

Toxins in bloodstrea: Bacteria in the colon release toxins as part of their normal digestion of nutrients. Typically a normal functioning liver can handle that. When someone has cirrhosis and the liver doesn't work normally those toxins can build up and get into the brain to cause the sleepiness/confusion of hepatic encephalopathy. That is why we use drugs like lactulose for diarrhea to clear the colon.