I have a D.I. dog.
What Squish said is spot on. There are SO many other things that can cause the excessive drinking of a dog that may not be diabetes insipidus. There’s really no ‘official’ way to diagnose D.I., you simply have to rule out everything else first and then do a trial with desmopressin acetate which is the synthetic form of the hormone, which is an anti-diuretic, that D.I. dogs don’t produce or the kidneys can’t use…
With my dog, we had to rule out diabetes mellitus, kidney disease, urinary tract infection, Cushing’s disease, cancer, etc. The only thing that really was a red flag in all of his bloodwork and urinalysis was his urine specific gravity was 1.001. We ruled all of those out, did a water deprivation test (which came back with the exact same specific gravity of 1.001) did a 30 trial with the desmopressin and had great results for about 3 weeks, then the drug no longer worked. Did more testing, went to an internist for an ultrasound, and found that my dog, T.C., actually had Cushing’s disease (though earlier tests ruled it out). We thought we’d found the problem.
Did 6 months of playing around with Cushing’s meds, got the Cushing’s under control (cortisol finally within low normal limits), but water intake was still excessive. Specific gravity only improved to 1.010 on a good day. Once again, had to rule out urinary tract infection first…ruled that out, tried twice daily dosing of Cushing’s meds, and concurred there was something else going on in addition to the Cushing’s. Started another 30 days on the desmopressin and this time, with the Cushing’s controlled, we’ve finally been able to control his water intake (and have controlled it since early August).
Prior to diagnosing both the Cushing’s and the D.I., T.C. was consuming approximately 150-180 oz of water each day (he weighs 55 pounds, so his water consumption should be in the 60-80 oz range). With the addition of the Cushing’s meds, his water intake dropped to about 120 oz per day, and with the addition of the desmopressin, he now holds stead between 70-80 oz per day. He’s on the smallest dose of the desmopressin (one drop once per day, though when he seems to be hanging at the water bowl a lot in the late afternoons, I often will give him a 2nd drop in the evenings)
The desmopressin is EXPENSIVE. One tiny bottle costs me $125. I can get two months out of it on a tiny dose, but most dogs require 4-6 drops per day. I’m happy that I’m able to control him on the minimal dose, as his Cushing’s meds aren’t cheap either! He’s lucky his mom loves him dearly.
Many people choose not to treat the D.I. It’s definitely not a death sentence. You simply MUST be sure that the dog has water 24/7 and limit their activity outdoors when it is especially hot and humid. A D.I. dog can dehydrate incredibly quickly. The issue with not treating, if you dog does have D.I., is that with the excessive water intake comes lots of urination…sometimes in the house if they can’t hold it while the owner is out.
There is some very good, user friendly, information at the website (though the individual who originally posted it all had a cat with D.I.):
http://www.surroundedbycats.com/di-whatisit.html
My dog has the Central D.I. type. Because he has pituitary based Cushing’s disease, it sort of makes sense that with a pituitary tumor, his pituitary either isn’t storing or isn’t releasing the anti-diuretic hormone produced by his hypothalamus.
All of that said, Diabetes Insipidus is pretty rare. It is often misdiagnosed because so many other diseases/conditions cause the exact same symptoms.
