How common are bladder stones in sulcata tortoise?

[Rex1718]

Ive read the cause is mainly poor diet and dehydration. How common is it for a tortoise to develop a bladder stone?
I’ve also read that most of the time they show no symptoms. What is the prevention method, taking the tortoise to the vet for X-rays every so often?
Thank you

 

[Markw84]

Sulcatas do seem quite prone to stones (uroliths). There is just so much we are still learning about tortoises and this is one area that needs more research. I believe the tortoises that burrow and go through periods of aestivation in the wild are more prone to stone development. They are "built" to hold water supplies for long periods of time as they have to go through long periods with no access in their dry seasons.

In captivity we mess all this up. There seems to me to be some key factors at work.

Uroliths in tortoises are, by examination, ALL purine based. No calcium based uroliths have been found. So it is the by product of protein digestion that creates a higher concentration of uric acid in the water being held by the tortoise. Tortoises do not create urine as it is more toxic in higher concentrations. So they hold uric acid which can then precipitate into urates that separate from their "water supply". The urates can be elimiated along with other waste without having to dump much water at all from the system. If dehydrated, or if concentrations are quite high, these urates can be come grainy and form the nucleus for a stone to develop if conditions do not allow it to pass out of their system.

So - protein in the diet will mean higher uric acid creation. If well hydrated, kept at optimal temperatures for metabolism, room to exercise and facilitate gut movement, and plenty of fiber to help move things through the system, this should all "work itself out". One or more of those factors missing can often lead to problems.

Many people often keep their sulcatas too cool, especially at night. They find the "do just fine". But uric acid precipitation is dramatically affected by temperature in the 60° - 90° range. Much more uric acid can remain in solution at 90° and at 60° most will precipitate. So the lower metabolic activity is exacerbated by high precipitation levels - plus we have a tortoise that is not motivated to move much at those temperatures. So not walking about much, nor wanting to drink and refresh the water supply.

If you watch a sulcata when it comes across water, or you run a hose in front of it, it will take advantage of the water by dumping the higher concentration water in its system and replacing it with good fresh water. A key measure to keep uric acid levels lower when water is available and - in the wild - this is the time they are most active and eating the most - when water is also available.

So what is the prevention method?

Keep water available always. Ensure your tortoise is well hydrated.
Keep protein intake lower, and ensure high, long fiber content in the diet (grasses)
Keep the tortoise warm - even at night. Be sure it can warm its body to at least 85° or more each day.
Give your tortoise enough room to be able to get good exercise and room to roam.