Searching for Cause of Death

Question
2 wks ago we lost our beloved 3 yr old house rabbit.  He was 5 wks post op bladder stone removal surgery by a very exp. rabbit vet. A course of antibiotics were given and he appeared to make a complete recovery.  He was eating/ drinking/urinating/pooping as normal. I awoke to hear him thrashing about on his side and he died very quickly. Vet out of town, necropsy done 2 days later,no cause found, heart not enlarged. I didn't want to send his heart out. Any ideas?

Answer
Dear Marilyn,

I am very sorry about your loss.  Unfortuntately, it may never be possible to know exactly what happened.  If a veterinarian doing a post-mortem exam could not determine the cause of death, I certainly cannot do so from this distance.  However, I can offer a couple of possibilities (and no confirmation).

If the post-mortem exam was only a gross examination, and no tissues were sent for histopathology, then there is just no way to know for sure what happened.  It could have been a stroke, an embolism (more likely after surgery, though still not common, especially 5 weeks later), or sudden cardiac arrest.  But sometimes even a post-mortem exam does not reveal what histopathology might.  And even histopathology might not indicate a stroke or embolism.

I wish I could be more help.  But please accept my sincere condolences.

Dana