Posts Tagged ‘pituitary gland’

A Primer on Diabetes Insipidus

Sunday, March 4th, 2012

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.

Ovariectomy (OVE) Versus Ovariohysterectomy (OVH) Revisited

Monday, December 26th, 2011
Licensed under a Creative Commons Attribution License.

Photo Credit: Roger H. Goun

If you’ve been reading my blogs for awhile now, you may remember two of my previous posts. While OVH surgery involves removal of the uterus and both ovaries, with OVE surgery just the ovaries are removed. Both are effective techniques for spaying (neutering) female dogs and cats. I am bringing this topic to your attention for a third time based on a recently published article within the Journal of the American Veterinary Medical Association.

The article is titled, “Ovariohysterectomy Versus Ovariectomy for Elective Sterilization of Female Dogs and Cats: Is Removal of the Uterus Necessary?” Let me get right to the article’s punch line by presenting the authors’ final paragraph:

We do not believe that there is any scientific evidence for the preferential teaching of ovariohysterectomy instead of ovariectomy by schools and colleges of veterinary medicine in the United States and Canada, and it is our view that ovariectomy provides an equally effective technique for elective sterilization of female dogs and cats with no recognized disadvantages. Potential advantages of ovariectomy include a smaller incision, better viewing of the ovarian pedicle, and possibly less risk of complications associated with surgical manipulation of the uterus.

The authors’ conclusion is based on a review of recent literature comparing these two surgical techniques. When I’ve previously recommended OVE as the spay surgery of choice, here are the two concerns that you, my readers have voiced:

  1. You are unable find a surgeon who will perform OVE surgery. Here is what I recommend. Call multiple veterinary hospitals in your community and ask if the vets on staff are willing to perform ovariectomies (if the receptionist is uncertain about what you are asking, you may wish to tactfully ask to speak with a veterinarian or technician). If nothing else, you will be raising awareness about this recommended alternative. Based on what you’ve told me, some of your vets have been willing to educate themselves and perform their very first OVE surgery in response to their client’s request, and the results have been fabulous. If one is adept at removing ovaries and uterus, removing just the ovaries is a “no brainer.” So, it is perfectly fine if your vet performs his or her very first OVE on your dog or cat (I would normally strongly advise against your pet being your vet’s “first” surgery or procedure of any kind). Board certified surgeons gladly perform OVE surgery and may do it the conventional way (incision made on the underside of the abdomen) or via laparoscopy (a method that employs scopes which are introduced into the abdominal cavity via small incisions). The only drawback to having a specialist do the work is that the price tag for the work will be considerably higher than the norm.
  2. You have voiced concern that if the uterus is not removed, your pet could develop pyometra, an accumulation of pus/infection within the uterus that necessitates its surgical removal. Please don’t buy into this ridiculous notion! Pyometra only occurs under the influence of progesterone, a hormone produced by the ovaries. Without the ovaries no progesterone is produced and there is no risk for development of pyometra. Period!

I want to emphasize that if you cannot find a surgeon who will perform OVE surgery on your dog or cat, no biggee! There is truly nothing wrong with removing the uterus. I only wish to create recognition for the fact that it is completely unnecessary to do so. Lastly, if you are contemplating spaying your older pet (her uterus has been around the block a few times), visual inspection of the uterus at the time of surgery is warranted. If the uterus appears abnormal, it should definitely be removed- the one situation where OVH rather than OVE makes perfect sense.

Has your pet recently been spayed? Which surgical procedure was performed?

Happy holidays to you and your loved ones,

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. 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 is available at Amazon.com, local bookstores, and your favorite online book seller.

Even More to Say About a Better Way to Spay

Thursday, March 17th, 2011
In January I wrote a piece called, “A Different Way to Spay” (http://speakingforspot.com/blog/?p=1931) describing two techniques for performing spay surgeries.  The method widely embraced in the United States is ovariohysterectomy (OVH) in which both ovaries as well as the uterus are removed.  The second way to spay- popular in many other countries- is ovariectomy (OVE) in which only the ovaries are removed and the uterus is left behind.  

Charlotte, OVE spay at 7 months © Kathie Meier

Since publishing the piece, many of you wrote to me expressing your frustration at not being able to find a veterinarian willing to perform OVE surgery.  I’ve written about those comments and provided an overall update on this topic for PetConnection.com- I sure hope you will read it (http://www.petconnection.com/blog/2011/03/15/a-better-way-to-spay-your-dog-that-you-probably-never-heard-about/).  Additionally, Dr. Tim McCarthy, a wonderful PetConnection colleague provided a response blog discussing the benefits of performing spays via laparoscopy- a form of minimally invasive surgery (http://www.petconnection.com/blog/2011/03/17/another-better-way-to-spay-that-you-probably-never-heard-of/).     

I look forward to your feedback about both articles.  If you are new to PetConnection, I hope you will follow my blog posts there as well as the ones you find here at Spot Speaks.     

Best wishes for good health,      

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
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. 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 is available at Amazon.com, local bookstores, and your favorite online book seller.   

    

 

A Different Way to Spay

Sunday, January 2nd, 2011

This blog presents an idea that will be new for many of you and may be new for your veterinarians as well.  I thought presenting a novel idea would be a great way to kick of the new year! 

Taking a fresh look at the things we take for granted can be wonderfully enlightening.  Sometimes, the little light bulb overhead begins to sizzle and sparkle, illuminating a new and better way of doing things.  Consider this example- when some savvy veterinarians took a fresh look at performing spays, a surgery we’ve been doing the exact same way for decades, guess what happened!  They came up with a revised technique that accomplishes all of the objectives of the spay surgery with fewer complications!  How cool is that!

Spay is the term used for neutering a female dog.  As I was taught in veterinary school, the medical jargon for spaying is ovariohysterectomy (OVH). “Ovario” refers to ovaries, “hyster” refers to uterus, and “ectomy” means removal of.  In other words, spaying the traditional way involves surgical removal of the uterus and both ovaries.  The objectives of the spay surgery are to render the dog infertile, eliminate the mess and behavioral issues associated with a female dog in heat, and prevent diseases that may afflict the uterus and ovaries later in life.  Thanks to some innovative veterinarians, what we now know is that ovariectomy (OVE)- removal of just the ovaries sans uterus accomplishes these objectives just as effectively as does the OVH.  And, here’s the icing on the cake- removal of the ovaries alone results in fewer complications when compared to removal of the ovaries and uterus combined.

Here’s a simple short course in canine female reproductive anatomy and physiology that will help explain why leaving the uterus behind makes sense. The shape of the uterus resembles the capital letter “Y”.  The body of the uterus is the stem and the two uterine horns represent the top bars of the “Y”.  An ovary is connected to the free end of each uterine horn by a delicate structure called a fallopian tube (transports the egg from the ovary into the uterus).  While the uterus has only one purpose (housing developing fetuses), the ovaries are multitaskers.  They are the source of eggs of course and, in conjunction with hormones released by the pituitary gland, ovarian hormones dictate when the female comes into heat and becomes receptive to the male, when she goes out of heat, when she ovulates, and when her uterus is amenable to relaxing and stretching to house developing fetuses.  After the ovaries and the hormones they produce have been removed from the body the uterus remains inert. The dog no longer shows symptoms of heat, nor can she conceive. Additionally, any chance of developing ovarian cystic disease or cancer is eliminated.

What happens when we leave the uterus behind- is it not subject to becoming diseased later in life?  Here’s the good news- the incidence of uterine disease in dogs whose ovaries have been removed is exceptionally low.  Pyometra (pus within the uterus), is the most common uterine disorder in unspayed dogs, and typically necessitates emergency surgery to remove the uterus.  Without the influence of progesterone, a hormone produced by the ovaries, pyometra does not naturally occur. The incidence of uterine cancer is extremely low in dogs (0.4% of all canine tumors)- hardly a worry, and studies have shown that the frequency of adult onset urinary incontinence (urine leakage) is the same whether or not the uterus is removed during the spay procedure. 

If you are not already convinced that the “new spay is the better way”, consider the following complications that can be mitigated or avoided all together when the uterus remains unscathed:

– Compared to an OVH, an OVE requires less time in the operating room.  This translates into decreased likelihood of anesthetic complications.
– Removal of the uterus requires that the surgeon perform more difficult ligations (tying off of large blood vessels and surrounding tissues with suture material before making cuts to release the organs from the body).  A uterine body ligation that isn’t tied quite tightly enough can result in excessive bleeding into the abdominal cavity and may necessitate blood transfusions and/or a second surgery to stop the bleeding.
– The ureters (thin delicate tubes that transport urine from each kidney to the bladder) run adjacent to the body of the uterus.  If a surgeon is not being extremely careful, it is possible to ligate and obstruct a ureter in the course of removing the uterus.  This devastating complication requires a second corrective surgery, however damage to the affected ureter and adjoining kidney may be irreversible. 
– Removal of the uterus occasionally results in the development of a “stump granuloma”- a localized inflammatory process that develops within the small portion of uterus that is left behind.  When this occurs a second “clean up surgery” is typically required. 
– We know that the degree of post-operative patient discomfort correlates with the degree of surgical trauma.  No question, of the two surgical options the OVH creates more trauma.

European veterinarians have been performing OVE’s rather than OVH’s for years.  In fact, the bulk of the research supporting the benefits of leaving the uterus behind has been conducted in Europe.  Slowly, veterinarians in the United States are catching on, and some veterinary schools are now preferentially teaching OVE rather than OVH techniques to their students.  What should you do if you are planning to have your dog spayed?  Talk with your veterinarian about this article and provide a copy for him or her to read.  Perhaps OVE surgery is already their first choice.  If not, perhaps your vet will be willing to take a fresh look at performing this old fashioned surgery.

Wishing you many blessings for the new year,

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
Recipient, American Animal Hospital Association 2009 Animal Welfare and Humane Ethics Award
Recipient, 2009 Dog Writers Association of America Award for Best Blog
Recipient, 2009 Eukanuba Canine Health Award
Become a Fan of Speaking for Spot on Facebook 

Please visit http://www.speakingforspot.com to read excerpts from Speaking for Spot. 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 is available at Amazon.com, local bookstores, and your favorite online book seller.