post-mortem diagnosis for cause of cecal impaction?

Question
Hi Doc,

I just lost my first pet rabbit. He was the softest, cutest and disapproving-est little bunny you could find for miles around. It was a cecal impaction that got him, despite getting him to an experienced vet who has saved the lives of luckier bunnies.

Of course, it's tearing me up inside not knowing why my bunny got sick. On one hand, maybe his diet was just too poor in fiber, though he always had hay, greens and alfalfa-free pellets. Too many carrot treats? How much carrot is too much? How do you say no to floppy ears?

On the other hand, the vet thought it could have been a case of leporine dysautonomia and has suggested doing the necessary histopathology. Having read your posts about "cowpoop" bunnies, I began to wonder: is it the same thing as dysautonomia? The vet did not detect any intestinal scarring, however I'd often noticed hard, misshapen poops over the short time I had the little guy.

The mystery is almost as devastating as the loss. Any advice on what to ask the vet about the necropsy would be very welcome.

Take care
-Ian

Answer
Dear Ian,

I am very sorry for the loss of your treasured friend.  How very sad for this relatively unusual problem to strike you so soon.  :(

"Dysautonomia" is a sort of catch-all phrase for any disorder of the autonomic nervous system, such as that innervating the intestines.  Bunnies with "cowpoop syndrome" are so afflicted from birth.  Most of them have piebald (white with dark patches) coloration and dark eyes.  The dark ridge of color along the back and lighter colors beneath are a visible manifestation of a failure of certain types of embryonic cells--those which give rise to both pigment cells and the nerve cells of the intestine and other organs--to migrate properly during development.  There is no cure for this problem.

That you saw large, misshapen poops in your bunny from the start is a clue that he might have been a victim of this congenital disorder.  If the vet does do a necropsy, I'm sure he will let the lab know that special attention should be paid to the histopathology of the intestines, and especially their innervation.  So whatever special stains needed to reveal a deficiency there should be used.  (I'm not a histologist; that's my husband's territory.)

The histopath might not show anything.  But it might also give you peace of mind that this condition was not something you could have prevented.  Your little sweetie may have had a ticking time bomb in his tummy, and it was only a matter of time.

I am so sorry.

Dana