Granular Casts - what are they?

Hi all! Cairo went back for his 2-week check-up for his soft stools. The doctor says she keeps seeing granular casts in his sample and she finds it worrying. His droppings look somewhat normal to me, depending of course on what he eats.

Her vet tech (who called me after work since my partner had to bring Cairo in without me) said that best bet is he's sensitive to melons (especially since melons aren't really what his species would have regular access to). Worst case would be a kidney problem.

To check for his sensitivity/allergy, we're cutting out all fruits that aren't coconut (a once a week treat) and apples (a small amount when my partner has an odd craving during the day, probably twice a week). I tried asking what diet should we go on to preempt any worsening of a potential kidney problem, but they said his current diet is actually sufficient for now.

But they keep mentioning it's the granular casts that are concerning, but wiki isn't helping me be enlightened.

So what are granular casts? How are they formed? What do they mean - best and worse case? What can we do?

I've heard the term in connection with urinary deposits in mammals...
Birds? Hmmm...
Hopefully your vet (or tech) could give you more info.

Meanwhile, for your perusing pleasure...
https://www.google.com/search?q=bir...rome..69i57.6294j1j8&sourceid=chrome&ie=UTF-8

My dog had casts in her urine once. They are microscopic particles that depending on the amount could be caused by anything ranging from something minor to something severe like kidney problems or poisoning. In my dogs case she had a lot of it so the vet suspected poisoning because on that paticular day she was fine in the morning and then my husband took her to his warehouse with him and she started acting strange there. He thought that she may have gotten into anti freeze or something. So he wanted to keep her overnight for tests and then 2 hours and 5 hundred dollars later he called me to say she is just stoned. Apparently one of the guys that work for my husband dropped pot on the ground and the big dummy ate it. I hope it just turns out to be something minor for your bird.