Hormonal Disorders of Dogs


Increased Appetite in Springer - Hyperadrenocorticism?

Q: Dear Dr. Richards,

Several months ago, you replied to my concern about our Springer'saggression. Your advice was very helpful, we have successfully avoidedtheconditions that provoked the biting.

Phoebe is eleven now and other than osteoarthritis (treated with Cosaquinand Rimadyl) she is in good shape, she is trim and pretty spunky forherage. Recently, she has developed quite an appetite and is very tenaciousin her quest for food and treats. Her weight and behavior is otherwisethesame as it has been. She is drinking more water, but not excessivelyso.I've no noticed any increase in urination.

She has a never empty bowl of senior/low fat lamb and rice kibble andinthe evenings she gets a 5 oz can of senior lamb and rice. Her dinnerisalways enhanced with a small amount of human food and throughout thedayshe gets about 5-8 small dog biscuits. Since she has never been aneagereater, we always gave her whatever she wanted, most times dog foodwouldbe left over or biscuits left uneaten. But now, she eats everythingand aslong as we are in the kitchen she begs.

Could this sudden change in appetite a symptom of a disease, like diabetes or Cushings? And if so, what should we be doing about her diet ortreatment? Could this be a consequence of a year of taking Rimadyl?Pleaselet me know your thoughts on this.

Yours truly, Diane

A: Diane-

Appetite changes like this are often associated with the developmentofhormonal disorders and diabetes and hyperadrenocorticism (Cushing'sdisease) are two very good possibilities. I am assuming that Phoebeis noton any medications --- prednisone, phenobarbital and several othermedications cause an increase in appetite. Once in a while we see anincrease in appetite with kidney disease and with liver disease butthis isusually very short term and then there is a decrease in appetite overtime. There are some odd causes of increased hunger, such ashyperthyroidism due to thyroid gland tumors or brain tumors. Some dogsalsohave increases in appetite with other cancers and often have weightlossdespite an increase in appetite.

The first things to look for are diabetes and Cushing's disease.Hyperadrenocorticism is probably the most common cause of increasedappetite in dogs over 9 years of age so it is worth running the specializedtests, such as the low dose dexamethasone suppression test, to ruleoutthis problem.

Mike Richards, DVM1/22/2001

Increased Water Intake

Q: Dr. Mike, Our 10 yr. old toyPoodle has started drinking three time the water she use to, and unableto hold it during times of our absence, therefore messing in the house.Our vet contributed it to indoor heat during the winter and her age. Butthat doesn't solve the problem. Help!! Thanks,

A: There are times when you justhave to talk to your vet about taking a problem seriously. When an olderfemale poodle starts to drink much more water it is very likely that shehas diabetes or hyperadrenocorticism (Cushing's disease). Kidney failureis also possible. It is worthwhile to do the labwork necessary to ruleout these problems.

Sometimes, I look back at my records or I think over the end of a dayand realize that I shortchanged someone by not really listening to themor by getting distracted when I should have been thinking. Sometimes, aclient won't hear what I am saying for similar reasons, probably.

Perhaps your vet did test for these problems and was left with the optionof making a "best guess" as to the other possible causes for the symptomsseen. If not, you really do need to let him know you want this looked intofurther.

Mike Richards DVM Hypoglycemia(Low Blood Sugar) in a Young Dog

Q: Our dog has hypoglycemia that becomes acuteabout once a month. We have been to a neurologist, nutritionist, and severalvets. The latest theory of one is that it could be insulinoma. My questionis would insulinoma produce excessively low blood sugar (25, for example)as seldom as once a month with normal (90-116) periods between? The pupwas just one year old. We got him from a breeder as a rescue pup becausethe breeder thought it was epilepsy. I'd appreciate any information youcould give.

A: I am not a specialist at anything, just a generalpractitioner with a lot of books. Just a warning, since sometimes peoplethink I actually remember all this stuff or that I might be a specialistin some field.

It would be very helpful to know what breed of dog you have and howbig he is. Toy breeds are prone to hypoglycemia at young ages because ofliver glucose storage/utilization problems. Hunting dogs seem to get atransient hypoglycemia when worked that I have not seen an explanationfor. Insulinoma is a possible cause of hypoglycemia because an insulinproducing tumor would make it hard to keep blood glucose levels up. Thisis probably the most common cause of hypoglycemia but my understandingis that it is much more common in older dogs. Liver disease is reportedto cause hypoglycemia at times. I have seen severe hypoglycemia in a dogwith bacterial septicemia --- but it was very very ill, as you might expect.That leaves the one mystery disease that always seems to be possible whenevera dog just isn't doing "right". Hypoadrenocorticism (Addison's disease)can sometimes cause hypoglycemia. It is usually mild but it can get severe.It is usually accompanied by other signs, like inappetance, vomiting, weaknessor slow heart rate, but sometimes hypoglycemia is the only noticeable sign.Whenever I feel stumped by a situation in which this disease is remotelypossible, I test for it as long as the dog's owners don't mind paying forthe testing.

The only problem with this list is that your vet and the specialistsare very likely to have considered everything on it. I don't think it istypical of insulinomas to cause really transient blood sugar drops. Itcan seem that way as the levels vary during the day but most of the timeit will show up with several blood samples or consistently with fastingunder close supervision. This may be a situation in which whatever is wrongis very untypical, though. That can make it very hard to get to the correctdiagnosis.

Good luck with this.

Mike Richards DVM


Michael Richards, D.V.M. co-owns a small animal general veterinary practice in rural tidewater Virginia. Dr. Richards graduated from Iowa State University's College of Veterinary Medicine in 1979, and has been in private practice ever since. Dr. Richards has been the director of the PetCare Forum...