Talyn, the Brazilian Rainbow Boa having the necropsy done, had a sepsis with multiple organ failure; with severe inflammation of the peritoneum and pericardium. The membrane around her heart was completely covered in fibrinogous material. Fibrin is a protein involved in the clotting of blood. It is a fibrillar protein that is polymerised to form a "mesh" that forms a haemostatic plug or clot (in conjunction with platelets) over a wound site. The fibrinolytic system is closely linked to control of inflammation, and plays a role in disease states associated with inflammation.
In this picture you can see that her heart is completely white: The entire pericardium is filled with it.
In this picture the membrane covering the heart has been opened and you can see that this protein material is stuck like glue all over the heart muscle.
As seen here, her liver was quite enlarged with signs of hepatitis.
Here you can see more of the fibrinogous material on and around the liver:
Her gall bladder was also unusually large. (The big green thing on the right side of the picture)
We saw that she still had residual eggs (much smaller than we saw on the ultrasounds -- In fact, they didn't even show on the last ultrasound).
These eggs had not been reabsorbed and some were necrotic and probably the source of the infection. The dark areas (pointed out by the green arrows) are rotting eggs. It was unclear if they had been fertilized or not.
The lesson to be learned here: Not only is egg-retention a problem in egg-laying species. Boas, although live-bearing, can die from retained eggs. Although the vet could not say if this tragedy could have been prevented, some possibilities would have been administrating antibiotics as soon as we could no longer see any eggs. Perhaps administering oxytocin (although this is not always effective) or high doses of calcium to stimulate expulsion of the eggs should have been tried.
The difficulty for us was that Talyn NEVER showed any signs of illness. She ate just 7 days ago! I handled her 2 days before she died. She did not act unusual at all. She climbed over me, over the sofa, and through the plants. She was not aggressive, nor reactive (although a severe peritonitis like that in a human would have caused excruciating pain.) She never vomited nor did she show any signs of agitation or difficulty breathing.
Although I wish I had done something to prevent this, I really had no warning signs at all.
Hopefully some of you with female snakes can benefit from the lessons learned here.