A Primer on Diabetes Insipidus

Photo Credit: Susannah Kay

Mention the word diabetes, and one thinks of insulin injections and blood sugar levels. This is because diabetes mellitus (aka, sugar diabetes) is so darned prevalent in people, dogs, and cats. But did you know that there is another version of diabetes, one that has absolutely no impact on blood sugar levels? It is called diabetes insipidus (DI). This form of diabetes is far less common, but as it happens, I diagnosed two patients (one dog and one cat) with DI within the last week. Go figure! As things tend to happen in “threes” I expect my third patient with DI will walk through the door next week!

Diabetes insipudus occurs when the kidneys are unable to conserve water. Under normal circumstances, the kidneys retain some of the water within the bloodstream for use within the body while eliminating the rest within the urine. This nifty little water conservation system is controlled by a hormone called vasopressin (aka, ADH or antidiuretic hormone). Vasopressin is produced within the brain’s hypothalamus. It is then stored and released from the pituitary gland, also within the brain. Now here’s the really cool part. There are sensors in the body that control exactly how much vasopressin is released into the blood stream after detecting exactly how much water the body needs. For example, if you are hiking in Death Valley and it is 110 degrees, your pituitary gland will release lots of vasopressin so that you produce minimal urine. Likewise, if you’ve just chugged a gallon of water, vasopressin release will be turned off thereby allowing your kidneys to “turn on the faucets.”

Diabetes insipidus occurs when vasopression is no longer released from the pituitary gland. Affected dogs and cats produce copious volumes of urine, and all that water loss results in profound thirst. Their dilute urine looks more like water than urine. In addition, affected animals  are prone to urinary accidents, saturation of their litter boxes on a daily basis, and the inability to make it through the night without urinating. Under such circumstances, people are sometimes tempted to restrict their pet’s water intake. This can be disastrous- even with water withheld, massive amounts of urine will continue to be produced and the animal will quickly become dehydrated. Fortunately, most animals with DI who are deprived of water will drive their humans crazy until they relent and fill the water bowl.

The diagnosis or DI is made by first ruling out other diseases that can cause increased thirst and urine output including: kidney disease, liver disease, urinary tract infections, diabetes mellitus and other hormonal imbalances.  The diagnosis is then confirmed based on a positive response to vasopressin therapy.

Trauma, infection, and cancer affecting the region of the hypothalamus/pituitary gland are all potential causes of DI. However, most cases of DI turn out to be idiopathic (an underlying cause cannot be determined). If your dog or cat has DI, your veterinarian will want to perform a thorough neurological examination. If neurological abnormalities are detected, a brain scan (MRI or CT) and collection of spinal fluid for analysis may be recommended.

The treatment for DI is vasopressin replacement therapy. This hormone is available in tablet and nasal spray formulations. The nasal spray must be fitted with an adaptive nozzle that allows application of the liquid as eye drops. Typically, marked reduction in water intake and urine output are observed within a few days to a week after beginning therapy. Other than the need to give daily, lifelong medication, the major drawback of treatment is that vasopressin is pretty darned pricey. It definitely pays to shop around at a number of pharmacies to obtain the best price. Barring no significant underlying brain disease, the prognosis for a patient with DI is excellent, and that’s definitely something that we internists don’t get to say frequently enough!

Have you any experience with diabetes insipidus? If so, please share what you know.

Best wishes,

Nancy Kay, DVM

Diplomate, American College of Veterinary Internal Medicine
Author of Speaking for Spot: Be the Advocate Your Dog Needs to Live a Happy, Healthy, Longer Life
Author of Your Dog’s Best Health: A Dozen Reasonable Things to Expect From Your Vet
Recipient, Leo K. Bustad Companion Animal Veterinarian of the Year Award
Recipient, American Animal Hospital Association Animal Welfare and Humane Ethics Award
Recipient, Dog Writers Association of America Award for Best Blog
Recipient, Eukanuba Canine Health Award
Recipient, AKC Club Publication Excellence Award
Become a Fan of Speaking for Spot on Facebook

Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot and Your Dog’s Best Health.   There you will also find “Advocacy Aids”- helpful health forms you can download and use for your own dog, and a collection of published articles on advocating for your pet’s health. Speaking for Spot and Your Dog’s Best Health are available at www.speakingforspot.com, Amazon.com, local bookstores, and your favorite online book seller.

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One Comment on “A Primer on Diabetes Insipidus

  1. Hi Dr. Kay,

    Are you aware that there is a Yahoo group dedicated to DI? It can be found at:

    http://groups.yahoo.com/group/diabetes_insipidus_dogs

    I had a berner with it and here are some of my experiences…

    I ended up using the nasal spray as an injectable with my vet’s OK after I showed her all the research I had done and shared other’s experience doing it that way. It was SO much easier for both my dog and I. Below is a post I sent tot he Yahoo! group mentioned above that summarizes my experience. Siskiyou lived another 2.5 years to 12.5, a ripe old age for a bernese.

    Hi All,

    Many thanks to those of you who sent me the info about how they are using the injections. It was very helpful!

    Siskiyou has been on injections for a little over two weeks now. The first thing I want to note is how EASY it is. I thought it was going to be a real hassle, be painful to her and just be a general challenge two times every day. Well it’s not, it’s actually easier and faster than giving her the pill, not to mention that it works significantly better and is much cheaper. (It’s also far easier than the eye drops and doesn’t waste any of the precious liquid.)

    She is still having a few accidents once in a while but her specific gravity is in the normal range and I think the accidents are due more to her senior age and the muscles being weak than from the CDI. (She has lots of problems with her hind quarters.) But it is nothing like the day she peed over 18 times! (Most of them in the house.) When we decided that the pill wasn’t working and that it probably wasn’t CDI, I took her off of it and her number of accidents skyrocketed. So as a last ditch effort we decided to try the injections, and not only are they working nicely so far, they are not causing the weird reaction that the eye drops were.

    Here is what I have collected from others that are using the nasal spray as injectable.

    ************************
    • Needle size: 31 gauge
    • Needle length: 5/16
    • syringe size: 3/10cc
    • % DDAVP solution (Nasal Spray): 0.01%
    • Amount of ml used for each injection: 0.05 ml (5 units on the 3/10 cc syringe) recommended dose is between 0.02 – 0.05 ml twice a day
    • # of times per day: twice
    • Where you get it: http://www.canadapharmacy.com
    • Bottle size: 5 ml
    • Cost of bottle: $80.00
    • How you transfer it to a dosing bottle: with a 1 ml syringe
    • Any side effects noticed: none

    ************************
    • Needle size: 29 g
    • Needle length: 1/2″
    • syringe size: ?
    • % DDAVP solution (Nasal Spray): 0.01%
    • Amount of ml used for each injection: We started at 0.05ml (5 units) twice a day and we able to get him down to 0.015 ml (1.5 units) 3 times a day
    • # of times per day: 3
    • Where you get it: Pharmacy at my local grocery store.
    • Bottle size: 5 ml (There is actually more in the bottle to prime the nasal pump and ensure a full 50 doses – almost 6 ml.)
    • Cost of bottle: $93.55
    • How you transfer it to a dosing bottle: Used a sterile syringe to transfer to sterile veterinary red top blood collection tubes.
    • Any side effects noticed: None

    ************************
    • Needle size: 29 gauge
    • Needle length: 1/2 inch
    • syringe size: ?
    • % DDAVP solution (Nasal Spray): don’t know the % but it’s 10mcg/50 5ml
    • Amount of ml used for each injection: .02ml
    • # of times per day: twice daily
    • Where you get it: http://www.Americanmeds.com
    • Bottle size: 5ml
    • Cost of bottle: $98.00 includes express shipping
    • How you transfer it to a dosing bottle: large syringe our doctor gives us (the stuff I get comes in a glass bottle with a separate sprayer, which makes it much easier to do)
    • Any side effects noticed: weight loss, but we’re not sure that has to do with the ddavp

    ************************
    • Needle size: 29G
    • Needle length: 1/2″
    • % DDAVP solution (Nasal Spray): 0.1mg/ml
    • Amount of ml used for each injection: 0.02 to 0.03 ml
    • # of times per day: twice a day
    • Where you get it: from the vet
    • Bottle size: 2.5 ml, the compounding pharmacy splits it into two bottles.
    • Cost of bottle: I am starting to use the generic desmopresin, much cheaper.
    • How you transfer it to a dosing bottle: compounding pharmacy filter sterilizes it.
    • Any side effects noticed: None so far

    ************************
    Syringes:
    • WalMart, About 13.00 per 100
    • Costco, they run $22 or $26 for a box of 100
    • CVS, generic CVS 3/10cc insulin syringes 100 for 14.99, get the store brand, not the B&D which are much more.
    • Terumo U-100 insulin syringes that are 3/10 or 1/2 of a ml, needle is swedged on to syringe, the small size of the syringe makes small doses easy to measure. 1 unit = 0.01ml

    ***************************

    Hi Maria,

    It took me a ton of reading through the old emails to figure out how to switch to injections, I finally did a survey and in the email below this are the results. Injections are SO EASY! My dog also hated getting the eye drops when we were trying them (they also did not work very well for my dog).

    She’s a similar size to a GSD (a bit smaller at 75 lbs) she doesn’t even notice when she gets the injections. I make it a special time by getting the syringe all ready, then giving her a bunch of loves and petting and then just pull the fur back somewhere near her neck so I can see skin and slide the needle in, really, with the small needle size I use she doesn’t even know it. After I give it, I then do some more petting and loving and she thinks it is just a very special time, little does she know she’s getting meds!

    It is faster, easier and cheaper than both the drops and the pills (both of which we tried and had very limited success with, so little in fact that trying the injections was a last resort that we almost didn’t bother with). Well, I’m really glad we did.

    Here in Portland, OR I get my .01% DDAVP solution from a compounding pharmacy (Northwest Compounders, 503-352-3811) 5ml for $109.50, they take the Nasal Spray and transfer it to a multidosing bottle by screening it through a micro filter to remove any bacteria. This pharmacy does this often and knows what you or your vet are talking about when you call about it. They work with the specialist vet that we are seeing and she has several paitients with CDI.

    It is done in a certified clean room. I know many of the folks on the list just have it transferred at the vets office or do it themselves, but I don’t want to hassle with that for only $20-30 more spread over 3 months, it’s just not that much extra. Judging by the amount left in the bottle from when we started about 3 weeks ago, the 5ml bottle will last several months. I am giving her .02ml (=2 units on U-100 Low dose insulin syringe 2x daily). It is actually a lot less than the amount she was getting with the pills and works better because of the method of absorption by the body.

    If you have any questions I’d be glad to answer them as best I can, I found it really hard to get concrete and accurate info from reading the list as folks were not always very careful where they were putting the decimal points in referring the the amounts!

    So to summarize here is what I am doing:
    • .01% DDAVP Nasal Spray Solution transferred to a multi-dosing bottle (it has a rubber top that you can insert the needle into multiple times without causing leaking or contamination)
    • 3/10cc 30 gauge 5/16″ needle (also known as a U-100 low dose insulin needle) syringe
    • .02 ml given 2 times per day (also equals 2 units on the specific needle size mentioned above)
    • cost is $109.50 for a 5ml bottle transferred by a compounding pharmacy
    • the first batch of needles came from the compounding pharmacy at $22 for 100, they can be found cheaper
    • I swab the top of the bottle after every use with alcohol
    • the medication is stored in the refrigerator

    I hope that is helpful! Below is the email I sent to the group a couple of weeks ago trying to get the info to switch. It is basically a survey of what other people are doing. I want to emphasize again, injections are really easy and painless—I was so worried that it was going to be a hassle, but it’s not all.

    Cheers and good luck!
    Terri and Siskiyou
    Portland,OR