UNDER CONSTRUCTION, STILL JUST NOTES
Ammonia is cleared by the liver, and in liver failure it can be build up, causing neuropsychiatric toxicity and encephalopathy.
As this JAMA 2014 article notes, the diagnosis is clinical and is not based on ammonia levels.
In fact, in chronic liver failure, checking serum ammonia levels is of questionable value: If patient has clinical hepatic encephalopathy, then treat. If they do not have clinical encephalopathy, do not treat regardless of the ammonia levels. (In acute liver failure, ammonia levels can tracks with cerebral edema.)
If encephalopathy suspected, look for triggers: GI bleed, sepsis, metabolic derangements, SBP, hypovolemia, constipation.
[ ] Lactulose 15-30 mL PO
[ ] Rifaximin 550 mg PO
- If intubated patient can give Lactulose 15-30 cc 1-2 hours via NG until 3 stools. Alternatively, can give Lactulose 300 cc in 1L of water as enema (Mayo Clin Proc, Vol. 89, pg. 241).