Well, unfortunately he was in bad enough shape by the time I noticed the crystals that there was not much hope of recovery. I set about my course of trying to figure it out rather than shrug and always wonder what happened.
So apparently there isn't much known about reptilian gout, especially outside of the most commonly kept reptiles. It can manifest in swollen joints (which was not the case here), or manifestation of uric acid crystals in the organs or mucous membranes (in this case, the tongue). According to my contact at the zoo, this occasionally comes up without any particular rhyme or reason. Individuals will die after they become symptomatic while cage-mates that have been raised identically have no issues at all. He mentioned specifically seeing the issue with
U. pietschmanni, which I figured would interest any of you that keep that species. The issue tends to be related to diet or husbandry. Specifically, I was told that dehydration could be the issue, though all of my enclosures are on a timed misting system (and this doesn't seem to be the issue with the zoo animals, either). I do, however, find it interesting that I reduced the amount of spraying for the winter and just started increasing it again a week ago, right when the issues started becoming noticeable with this gecko.
I guess it's sort of nice to find out it was not a bacterial issue, but it's still frustrating not to have a more definitive answer as to why it happened in the first place. Nevertheless, it's on the record and here for everyone else to learn from.
LOOK OUT BELOW, NECROPSY PHOTOS.
I don't think it's easy to see in the pictures, but I could detect small uric acid crystals in the liver, though they were scarce. It appears as though larger uric acid crystals had formed inside the stomach, which can be seen faintly in the images above. The kidneys seemed to be highly affected by the uric acid crystals, showing a miniature shotgun-like appearance of tiny white crystals. I have more photos if others are interested.
