Bunny seizures and death

Question
We rescued our beloved Lucky two years ago from a abandoned yard. We brought her to the vet to be checked out and she was fine except for being dirty.  Lucky had an amazing life with us. She had the run of the kitchen, all the right foods, hay and everything a bunny needs. She was my baby and she got so much attention and love. About 7 months ago for no reason she started having seizures. She would have 2 or three a day for about 3 days. I took her to the vet when the I saw the 1st seizure and the vet could find nothing wrong with her. I cleaned out her entire cage and when I did I found some black mold under the flooring where the water   bottle drips. I used bleach and cleaned it up. Lucky only had one seizure after that. I thought I had solved the mystery and I was feeling great about being able to save my Lucky's life. Well...
Just about two days ago I noticed Lucky breathing differently. It was'nt such labored breathing as I read in other websites, it was just a slight change like she was slightly out of breath. This morning she had another seizure, then 2 more. I held her in my arms all day and comforted her. I put her on Baytril in case she had any infections of the lungs, although she had no runny nose. She had been eating hay and drinking plenty of water. She however stopped eating her favorite food. After the 3rd seizure she started mouth breathing. She had one more violent seizure before she died in my arms tonight. I do not know what to do with myself. I am feeling so guilty that I should have taken her to the vet right away but my last rabbit went thru so many medical tests and thousands of dollars at a hospital specializing in Rabbits and she ended up dying from the shock of being handled and put thru so many tests. $4,000 later and a broken heart I vowed that I would never put another loved pet thru that, but now I am feeling that Lucky could have had a chance if I did. She had some signs of messy poop but she sometimes did and she had a very sensitive stomach. I also want to tell you that I had'nt changed her poop pan for 4 days and it was in need of cleaning. I just had knee surgery and could not bend to reach it. Maybe she ingested some urine spores and they entered her lungs? I am feeling guily that I did not clean her pan right away. Please help me if you can explain what might have happened. I do not want to do an autopsy. I just coul'nt bear it. I miss her so much.
My vet thinks it could have been Encephalitozoon cuniculi. What is VHD? I have read that it causes seizures. Are seizures common in rabbits? and can they be cured? Could I have saved her?
Thank you so very much,
Kristin Balon

Answer
Dear Kristin,

I am so very sorry about the loss of your beloved friend.  

As you probably know, there is no way to definitively discover the cause of her death without a post mortem exam, which you don't want to do.  I can understand that.  But all I can do is offer some educated guesses.

First, it is not very likely that mold spores were the cause of this.  Mycotoxin poisoning usually happens over a long course of time, and symptoms become worse with chronic exposure, usually in the feed.  

I have some doubt that it was E. cuniculi, which is more often characterized by hind limb paresis, renal failure, and some neurological problems.  I have never heard of E. cuniculi positive rabbits having seizures, though I suppose it's not impossible.  No one really knows all the problems this parasite can cause.  We can't rule it out.

VHD, or viral hemorrhagic disease, is very unlikely to be the cause, as it kills relatively quickly--within a few days of exposure.  Though not all rabbits hemorrhage, the viral disease is characterized by bleeding from the eyes, nose, and all other orifices.  (It's a bit like "rabbit Ebola")

If the labored breathing was chronic, it is possible that Lucky had a thymoma, or enlarged thymus gland.  This can sometime impinge on the blood flow from the head, and though I have never heard of thymoma causing seizures, I suppose it would be possible.  Any mass in the chest (thymoma, lung abscess, other mass, such as a tumor) can cause labored breathing, and without a necropsy, there is just no way to know.

Whatever you do, please don't blame yourself for her death.  Whatever caused it was not a common thing, and would probably have required extensive radiography and other types of tests to determine.  And some of the things that could cause symptoms like (e.g., brain tumor or abscess) this might not even have been treatable.

I am sorry for your grief, and loss of Lucky.  But I hope that eventually you will start to heal and realize what a wonderful life you gave her, even if it was too short.  Lucky had you for her whole life, was spoiled and loved.  Most rabbits never even know the sound of a loving voice.  And even though Lucky was with you for too short a time, that time was golden for her.  

At the end, you gave her the greatest gift any friend could give:  your presence and comfort while she made that last journey in this body.  She was not alone.  She was with you, being held in the warm arms of the person she loved most in the world.  All of us should be so lucky when we cross over.

You will meet again.  In the meantime, I send healing thoughts and hope that you know that sometimes we're only human, and there's nothing we can do to save a mortal body whose time on this plane is up.

Take care,

Dana