Cat with ARF -- help!!

[Momto4pets]

I have a 14 yo cat named Ollie who was treated with I131 last year for hyperthyroidism. Since last Nov he has done great. He had followup blood work at 1/3/6 months post-iodine and had perfect kidney function each time. Last month at month 12, his Cr was 2.2 which was a little elevated. Since it had been perfect a few months before we decided to hydrate him at home and recheck it in a few weeks.

Unfortunately, he became extremely ill on 12/23. Out of the blue he had no eating, no drinking, and didn't recognize us. Also, his mouth stunk like an infection. I thought that maybe he had an abscess and took him in urgently. A few hrs later, they told me he was in ARF with BUN 130 and Cr 13.3. Phos greater than 16.1. They gave him IVF and abx. We had the choice to transfer him to the emergency vet for the holiday weekend, but I opted to do hospice at home since his chance of a great recovery was slim. I did sub fluids twice a day, Pepcid SQ, and encouraged eating. The Vet also gave him a shot of a long acting abx. Over the course of 2 days he perked up tremendously and looked a lot better. He's still not really eating or drinking, but is moving around and alert. His repeat cr was 13.0 yesterday. His electrolytes were somewhat improved and his phos had come down some. We're doing subQ fluids twice a day, Pepcid, some K, and trying assist feeding with an ICU diet.

Has anyone seen a cat decompensate this fast and recover? He didn't appear to have any pre-renal or post-renal cause for his ARF. I've trilled the net for the last 4 days looking for advice but wonder if any of you have been through this . The Tanya's Comprehensive Guide to Feline Chronic Renal Failure website has been a godsend.