Bladder stones in sugar gliders

Two of our sugar gliders recently underwent surgery to remove calcium oxalate bladder stones which were obstructing their cloacae, and which would have been fatal had they not been removed. Some years previous, we lost a glider to what, though it was misdiagnosed at the time, was also (in hindsight) almost certainly cloacal obstruction caused by a bladder stone.

There is virtually nothing on the Internet about bladder stones in gliders, and even the very experienced exotic-animal vets I consulted had never encountered them before, so I’m posting what we’ve learned (such as it is), in the hope that it will prove useful to other sugar glider owners and perhaps even save a life or two.

Symptoms

• General listlessness is the first symptom to appear: ears down, eyes dull, no interest in exercise. The glider will often avoid other colony members and sit by itself.


• Loss of appetite, soon developing into a refusal to eat or drink anything at all


• No urination or defecation, even when the cloaca is stimulated. The glider will make the panting/hissing sound which usually accompanies defecation, but nothing will come out.


• Instead of normal excretion, a foul-smelling brownish or whitish liquid may leak out of the cloaca. The fur around the cloaca may be wet even though there is no urination.


• You may (or may not) be able to feel a hard mass in the glider’s abdomen.


• One of our gliders suffered cloacal prolapse. The other two did not.


• A few days before the end, the glider who died began experiencing seizures and sudden attacks of rigor mortis-like stiffness. Once this starts happening, it’s probably too late.

Diagnosis and treatment

Gliders are too small for ultrasound, so the vet will have to x-ray it. Be sure he takes a side-view x-ray as well, since the tail bones may obstruct the view of a bladder stone lodged near the mouth of the cloaca.

For some reason, x-rays of sugar glider bladder stones look quite different from those of other animals such as rabbits and tortoises. A mass will be visible, but the fact that it is a bladder stone may not be obvious. When the vet operated on the first of our two recent cases, he was expecting to find an intestinal obstruction, which quickly leads to inoperable necrosis of the intestines. He told us that the chance of saving the glider was very very low, but fortunately we opted to go ahead with the surgery anyway. We sent him into the operating room fully expecting that we would never see him again, and when the vet came out with the announcement that it had actually been a bladder stone (much easier to operate on), it seemed like a miracle.

Surgery is, as far as I know, the only effective way to treat — and, in some cases, even to diagnose — a bladder stone in a sugar glider. It is a relatively low-risk procedure, and full recovery takes about a week.

Cause and prevention

Obviously, after having three gliders with bladder stones, we’ve been reconsidering the diet we’ve been feeding them. The stones are calcium oxalate, and gliders necessarily eat a lot of calcium (calcium deficiency can lead to paralysis and bone damage), so the most important thing is probably to limit their intake of oxalic acid (oxalate). This is the same advice given to humans who suffer from calcium oxalate kidney stones, and there are various “kidney stone diet” sites out there which give lists of high-oxalate foods. The main culprit in our case seems to have been spinach, which our gliders love but will not be allowed to eat anymore. (Low-oxalate green vegetables which can be used instead include lettuce and cucumber.) Other foods to avoid are potatoes, nuts and beans of all kinds, celery, and many kinds of berries. Of course, making sure they drink enough water is also important.

We’ve just started our gliders on a low-oxalate diet, so I can’t report on the results yet, but I certainly hope this will solve the problem and that no more operations will be necessary. I’ll be updating this post with any new information that comes my way, and I encourage comments from anyone else who has experience with this.

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