Pituitary Tumors /Pituitary Dwarfism in Dogs

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Pituitary based tumor causing Cushing's

Question: Dear Dr. Richards:

Thank you for your response. I am curious about your appraisal of my vet's recommendation that I treat with Lysodren. It sounds like I have no choice but to take a medical approach to this. My vet has prescribed Lysodren along with a sustaining amount of Prednisone (sp?) followed by another ACTH in 10 days. He says the success varies greatly with different dogs, good results could be apparent in 3 weeks, other times in 3 months, made evident by repeated ACTH tests. Once the optimal levels are achieved then they know what levels to prescribe and stick with. He cautioned me that some dogs need readjustment in the medications which is apparent by the return of symptoms or a routine ACTH test. My vet described the continued decline and other failures that are possible from not treating the dog and this strategy does not sound like an option. And this treatment could allow her to age normally, free of the current dibilitating symptoms. He also mentioned adjunct supplements - antioxidents to protect the organs from the Lysodren. Do you have any recommendations of specific diet, vitamins and food supplements? Thank you again. Laura

Answer: Laura-

One of the older issues of the VetInfo Digest in the subscriber area is devoted entirely to Cushing's disease. It has some information in it that is not available on the general web site.

The dietary recommendations in "Small Animal Clinical Nutrition, 4th ed.", Hand, et. al., are to use a low fat, moderate fiber diet with good quality protein. Vitamin supplementation is not thought to be needed if a food meeting the AAFCO requirements for adult dogs is being fed. Several of the therapeutic diets on the market meet these requirements, including Hill's w/d, Purina's DCO and OM diets (tm) and Walthams Low Fat (tm) diet. There are probably others, as well.

Hope this helps.

Mike Richards, DVM 7/19/2000

Pituitary based tumor in Brittany

Question: Dear Dr. Richards, My 8 and a half year old Brittany Spaniel named Lucy has been diagnosed with a pituitary based tumor causing Cushing's Syndrome. Her symptoms are insatiable hunger and thirst, bloated belly but no weight gain and much decreased activity level and fatigue. (She is normally an extremely active dog.) I do not yet have the full report from her ultrasound, but so far they ruled out an enlarged adrenal gland, therefore pointing to the pituitary gland. She had an ACTH test earlier as well leading up to this diagnosis. My vet has recommended Lysodren to address the symptoms, but which will not address the tumor. I am wondering about surgical options since we have a vet neuro surgeon here in Seattle (who is out of town until the19th.) Do you have any experience with surgery for this kind of tumor? If so, what success rate has there been and what effects does the surgery have on the dog? I am wondering if we try medical treatment first we will still have the surgical option later if the medical treatment isn't very satisfactory. Would treatment with Lysodren now rule out a surgical strategy later? Is there any urgency to medical treatment? Her symptoms just recently (the last month) got bad enough for me to realize she needed to be seen by the vet, but now that we have a diagnosis I realize that this has been building for about a year. Thank you. Lucy is a dear part of our family and we are very sad about this illness. Sincerely, Laura

Answer: Laura-

I am not aware of anyone doing transsphenoidal hypophysectomy (pituitary removal) surgery on dogs in the United States. Reports on this surgery have almost all come from Utrecht University in the Netherlands. It is hard to be sure whether or not a surgery is being done in the U.S. and where it is being done, since these situations change quickly, so you probably should talk to the surgeon in your area. He may be aware of someone who does this, if he does not.

I am not sure why surgery is not utilized more often in dogs since it is commonly done in people. It may be an economic decision but there have been reports of attempts to do this surgery in the US and they have not had outcomes as successful as those of Utrecht, so poor experiences with the surgery here in the US also has something to do with it.

I can't think of any reason why using Lysodren (Rx) now would interfere with surgery later but I haven't seen any journal references that discuss this.

The good thing about Cushing's disease is that there are treatment options now, making it more likely that you can find success in treating this condition.

Mike Richards, DVM 7/17/2000

Surgery for Pituitary Tumors

Question: Dr Mike,

This is Ruth again. Our present vet here in Louisville briefly mentioned that surgery can be done for pituitary tumors, and stated that this surgery is costly. What are your views as to this type of surgery??????? I have read that this type of surgery has been, and is being done, I believe, somewhere in the Netherlands? I also read that the success rate has not been that good; that the animals tend to fair the surgery itself, but has succumbed post surgery for various reasons. Have you heard anything about this??? Surgery is supposed to be costly, but what dollar signs are we talking about approximately???? What is your opinion of this surgery?????

Ruth

Answer: Ruth-

This is the information that I put in the August 99 VetInfo Digest (it is available in the subscriber area):

Surgical Therapy for PDH ( transsphenoidal hypophysectomy)

With the advent of accurate diagnostic imaging using CT or MRI scans, it has become possible to locate and remove pituitary gland tumors surgically at some institutions. The Utrecht University in the Netherlands is one place where this surgery has been performed a number of times. While the risk of surgery is pretty high, with 10% of dogs undergoing surgery dying from immediate complications and almost 10% of dogs having incomplete surgical excision of the affected portions of the pituitary gland, the two year survival rate of patients undergoing this procedure is still reported to be close to 80% by Meij, et al, in the May/June 1998 issue of Veterinary Surgery. I am not sure how available this procedure is in the United States but it is likely that it will become more common due to the increased availability of high quality imaging and advanced surgical facilities.

Limited reports from surgeons in this country seem to indicate a higher death rate from surgical complications than has been experienced by the surgeons at Utrecht.

I rechecked the databases online to see if there were new developments and couldn't find any. I do not know of any surgeons doing this surgery routinely in the United States but that doesn't mean that someone isn't. I had a hard time searching for vets who were doing kidney transplants in cats when a client wanted to find one, but our client was able to find a name after searching the web persistently. I don't know whether or not it would be possible to arrange for surgery at Utrecht but if you would seriously consider this I will try to find out for you.

Mike Richards, DVM 1/28/2000

Pituitary dwarfism / hyposomatotrophism

In Pituitary dwarfism / hyposomatotrophism a deficiency in pituitary stimulation of growth hormone production leads to dwarfism. This occurs most commonly in German shepherds but has been reported in several other breeds. It is an inherited disease in German shepherds (autosomal recessive trait). This disorder must be distinguished from other conditions leading to stunted growth, including malnutrition, congenital hypothyroidism and other congenital defects leading to poor growth. Dogs with this condition do not grow like their littermates. Their hair retains its "puppy" appearance, feeling soft to the touch. Hairloss along the sides that is symmetrical often occurs. Abnormalities in bone growth lead to a deformed appearance to the legs. As other puppies in the litter appear to mature, affected dogs continue to have a puppy-like appearance and bark. Dogs with this condition may be deficient in other hormones in which the pituitary gland controls part of the process of stimulating the hormone's production. It is a good idea to check for hypothyroidism and hypoadrenocorticism in dogs with hyposomatotrophism. Human growth hormone will work to treat affected dogs but it is expensive and may be hard for the average veterinary practitioner to obtain.

Mike Richards DVM

Research being done in genetics.

Dr Mark Neff a researcher / vet is trying to start a study on dwarfism in dogs but hasn't received enough participants. If you have a dwarf dog or puppy and would like to increase the knowledge base about this disorder you can enter the study. Our reader Sarah says that Dr Neff asked her some some questions about her pup and then she said she could send him a sample a cotton swab from the pups cheek to do some testing and see how to help Bailey. The more samples he has the more he can test and see how to develop better treatment options for dwarfism, perhaps even a cure. Sarah wanted to share the study information with everyone that had dwarf puppies and dogs. Anyone with a dwarf dog can submit a cheek cotton swab to Dr. Mark Neff at UC Davis e-mail: mwneff@ucdavis.edu If you need a phone number as well for him it's 530-752-1381 Dr. Mark Neff is a geneticist at the Veterinary Genetics Laboratory of the UC Davis School of Veterinary Medicine. He received his Ph.D in genetics from the University of Virginia and his postdoctoral training in the laboratory of Dr. Jasper Rine at UC Berkeley, where he helped assemble a genetic linkage map of the dog genome. He has worked with Canine Companions for Independence, in an effort to develop a 'temporal fate map' -- 'genetic markers' in puppies that could indicate which ones are more likely to make the grade as service dogs. He has been looking at developmental 'windows', times during which the dog's physical and psychological growth can be influenced. His work has direct application to the breeding process, evaluation of puppies, and the factors which can influence the development of those puppies. In addition he will address specific problems in the breed, such as lens luxation and deafness, and any issues raised by the participants. 7/22/2004

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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...

 

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