Mystery Illness - Shot in the Dark Here!

Okay folks, maybe I'm desperate and that's okay.  Here's the story.  I brought my sister into the ER here two weeks ago with what I thought was a stomach virus and a declined mental state.  I had seen something similar with my father a month and half earlier when he went into renal failure after having a kidney out due to cancer.  (He unfortunately lost his battle after it metastasized to his brain and skull.  I've seen mental confusion like you wouldn't believe.)  Anyway, my sister quickly declined and a ABG revealed a blood ammonia level of 192.  Liver and kidney function were normal.  CT scan of the brain revealed nothing.  She's had rheumatoid arthritis for the past seven years and a gastic bypass five years ago.  She was swept up the ICU unresponsive and eventually needed to go on a vent, and administered Lactulose, which didn't bring her ammonia down fast enough.  So she underwent a four hour course of dialysis.  This started to bring it down.  In the mean time, her potassium dipped.  Hepatic Encephalopathy ensued (of course).  Her ammonia level came down, potassium came up.  Her blood levels were all normal.  Her MRI of the brain, liver biopsy, EEG, blood tests, and lumbar puncture were all unremarkable.  She was put on an NG tube.  She came out of her unresponsive state a week later.  They took her off the vent three days after that, and she seemed pretty with it, but would be confused from time to time.  They moved her out of ICU and up to a regular room, but her mental state continued to decline.  This was chalked up to ICU Psychosis. Another MRI showed no brain damage, but her mental state was still very bad.  If anyone else has ever been around this, you know how hard it is to see your loved one go through this.   Last night, she started vomiting and spiked a high fever, was sent back to ICU and is back on the vent.  My mother thinks this was due to a kink in the NG tube that had to be straightened.  They are treating her symptoms with antibiotics.  We are still left with no answers as to the cause of the initial incident, if this is a continuation of the incident, a secondary infection or what.  We aren't sure if we should transfer her to another (better hospital), because we don't know what she has or who to see about it.  I know that not every medical incident has an explanation, but was wondering if anyone has ever experienced or even heard of something like this happening.  We're kinda beside ourselves here.  Thanks for reading this incredibly long post.  

[mkh9]

I'm so sorry for all that you have gone through. Normally since the livier breaks down the ammonia into urea it is a problem with the liver and/or kidneys. But since you said her tests were normal. There could also be bleeding into the intestines or heart problems. I assume they checked to see if she had Hepatitis? How old is she? if she is under 20 and had a flu or virus and was given aspirin she could have Reyes syndrome. But I would think that would show up on the liver scan. Did they actually do a CT or MRI of the liver and/or kidneys? I hope you are also taking care of yourself. Having such loss and trauma can really drag your health down too. I know because we went through something like this with my husbands brother in 2009.