Exam III: Hepatic Encephalopathy

Question 1

_____ is a toxin we can easily measure to aid in the diagnosis of hepatic encephalopathy.

Answer 1

Ammonia

Question 2

When monitoring hepatic encephalopathy, what should we monitor?

Answer 2

Mental Status

NOT AMMONIA

Question 3

Describe the grading scale for hepatic encephalopathy severity.

Answer 3

0 = Normal
2 = slow responses
4- unarrousable/comatose state.

Question 4

How should we treat hepatic encephalopathy?

Answer 4

1. Remove Precipitating Factors
2. Switch to dairy/vegetable sources of protein (decrease risk of crossing BBB)
3. Lactulose
4. Xifaxan [Rifaxmin] (only with lactulose)

Question 5

How does lactulose work?

Answer 5

It is a non-absorbable disaccharide which is fermented by the gut flora to produce organic acids that decrease the colonic pH.

The decreased colonic pH allows for ion trapping of ammonia moving from the gut to the bowel.

Furthermore, in the bowel ammonia is converted from NH3 to NH4, where it is then trapped in an ionized state in the bowel.

This ultimately leads to excess ammonia being eliminated in the feces.

Question 6

What is the dosing of lactulose for hepatic encephalopathy? (oral and enema)

Answer 6

Oral: 25 ml q 1-2 hours until at least 1-2 stools are formed.

Enema: 300 mL every 6 hours via retention enema for 1 hour.

Question 7

How should rifaximin [Xifaxan] be used for hepatic encephalopathy?

Answer 7

Only with lactulose.

Question 8

How does rifaximin [Xifaxan] work?

Answer 8

It is an old antibiotic which targets bacteria in the gut which produce ammonia.

Question 9

Rifaximin [Xifaxan] Dosing

Answer 9

Acute: 400 mg q8h

Prevention: 550 mg PO BID.