Thursday, March 17, 2011

Cushing’s Syndrome: A Common Hormonal Disorder in Dogs

Cushing’s syndrome, also called hyperadrenocorticism, is a disorder which results from the excess production of an adrenal hormone called cortisol. It is a common endocrine disease in middle-aged and older dogs. Miniature Poodles, Dachshunds, Boxers, Boston Terriers, and Beagles are particularly vulnerable.

What causes Cushing's syndrome in dogs?

There are three major causes for Cushing’s syndrome. The most common cause (85–90% of cases) is a small tumor in the pituitary gland. The pituitary tumor produces a hormone (adrenocorticotropic hormone or ACTH) that causes the adrenal gland to grow and oversecrete cortisol.

Less commonly (10–15% of cases), the adrenal glands themselves develop a tumor that secrete cortisol.

A third cause of Cushing's syndrome in dogs results from the long-term use of high doses of corticosteroid drugs such as prednisone or dexamethasone. These steroid drugs are used to decrease inflammation or treat an immune disorder.

What clinical signs do dogs with Cushing's syndrome develop?

Common clinical signs include the following:
  • increased thirst and urination
  • increased appetite
  • excessive panting
  • lethargy
  • pot belly appearance
  • weight gain
  • hair loss
How do we diagnose Cushing's disease in dogs?

Diagnosing Cushing’s syndrome can be difficult. Laboratory test results may be inconclusive and dogs suffering from other diseases commonly show false-positive test results for Cushing’s syndrome. (For more information, see this post on my Vet Blog.)

Once we have diagnosed Cushing’s syndrome, the next step is to determine whether the disease stems from a tumor of the pituitary or of the adrenal. This can be done by further endocrine testing or by imaging techniques such as abdominal ultrasound.

How do we treat this problem?

Most dogs with hyperadrenocorticism can be treated with drugs such as mitotane (Lysodren™ or trilostane (Vetoryl™). However, these drugs are most safe and effective when used under the supervision of a veterinarian with much experience their use.

If the dog has a tumor of the adrenal gland, surgical removal is generally the best option. Finally, external radiation therapy can help dogs with pituitary tumors, especially large ones.


Yvonne said...

Dear Dr. Peterson,

I have a cat diagnosed with cushing's syndrome (adrenal gland tumor) and pancreatitis as well. She is on Vetoryl 30 mg, 1 capsule a day.

I understand that taurine is helpful for liver and lipid metabolism et al. I also understand that taurine as a side effect may increase the effect of drugs.

Is it dangerous to give Vetoryl and additive taurine to my cat?

Thanks for your help!

Yvonne said...

Dear Dr. Peterson,

I have a cat diagnosed with cushing's syndrome (adrenal gland tumor) and pancreatitis as well. She is on Vetoryl 30 mg, 1 capsule a day.

I understand that taurine is helpful for liver and lipid metabolism et al. I also understand that taurine as a side effect may increase the effect of drugs.

Is it dangerous to give Vetoryl and additive taurine to my cat?

Thanks for your help!

Dr. Mark E. Peterson said...

Taurine is an essential dietary requirement for feline health, since cats cannot synthesize the compound. Taurine is not toxic in cats and is water-soluble, so any extra the cat can't use just gets flushed out in their urine.

Vetoryl doesn't always work very well in cats with Cushing's syndreome, so if the taurine allows the Vetoryl to work better, that would be great. The dose of the Vetoryl could always be lowered in that case.

Vader said...

Dear Dr.Peterson,

My name is Iraklis Proviadakis from Greece.

My doggie (husky) was misdiagnosed with arthritis ,because of hind leg mild weakness (couldn't run,just jog).
Was given cortisol.
Then misdiagnosed with liver cancer and was prescribed ,again, even more cortisol.
During this time he developed all the known symptoms of Cushings.

After a liver puncture (my decision, they insisted on euthanasia) showed increased corticosteroid cell numbers he was prescribed Vetoryl.

However, the vets did NOT follow the protocol (only ACTH test at 10 days) and increased the dose of 1*30mg to 2*30mg per day over the phone after the first month.
I was also not informed on the possibility of the pituitary enlarging because of this (chemical Nelsons' Syndrome).

This resulted in (after 2 1/2 months use of Vetoryl) in an enlarged pituitary (MRI verified 16th November) and many neurological symptoms.

Few questions:
When Husko got his LDDS (4th September) he was only off cortisol for 2-4 days...(weening off it slowly since August 24th)
and was on cortisol for almost 3 months non-stop prior to that with very large doses of it...
Could this situation have messed up the results?
1.14,20 μg/dL
2.16,40 μg/dL
3.13,40 μg/dL

On the 17th September (10 days after starting Vetoryl ,1*30mg)
His ACTH was
1. 9,84 μg/dL
2. 26,50 μg/dL

Could this and/or his LDDS be false positives?

After he had the MRI i stopped giving Husko Vetoryl and his cortisol level after 4 days off Vetoryl was
7,63 μg/dL

Was he ''borderline'' cushings from the start and probably do fine without any treatment for months/years?
His only symptom for months before visiting the vets was hind leg weakness due to muscle wasting.

My doggie has since died (14th March), and I want to do anything in my power so these vets won't kill another poor soul like my angel Husko with their poorly handled practice...
Your word counts!!!

Full complicated story here

Thank you very much from the bottom of my heart!
Iraklis & Angel Husko

Dr. Mark E. Peterson said...

Sorry to hear about your dog and your loss.

In answer to your questions:
1. Cortisol administration would not have interfered with the results of the low-dose dexamethasone suppression to produce false-positive results. Your dog definitely had Cushing's.

2. The ACTH stimulation test after Vetoryl was still very high. Use of cortisone could potentially cause a lowering of the endogenous cortisol values, but cortisol would NOT cause this hyper-response to ACTH stimulation.

3. Your dog's Cushing's was not borderline. It is very clear to me based on the test results that you provide that Cushing's was definitely the correct diagnosis. Not all dogs show all of the classic clinical signs. This is especially true in dog breeds in which Cushing's is not very common (e.g., Husky).

Vader said...

Dear Dr.Peterson,

My dogs' only symptom was 'hind leg weakness' ,but was misdiagnosed with arthritis,then later misdiagnosed with liver cancer (elevated liver enzymes).

During 3 months of cortisol administration ,all the known symptoms of Cushings developed!
Not before!

I accept he had Cushings.
But would you say that these iatrogenic 'errors' vastly accelerated the time it takes for Cushings symptoms to develop ,and that he would probably not even need treatment with Vetoryl (which most probably accelerated pituitary growth) ,for at least some months/years later?

His more detailed story/exams/results are here (a forum that highly respects you and members told me to contact you as the worlds best authority in these matters).

Thank you very very much kind sir!
Mr. Iraklis Proviadakis

Dr. Mark E. Peterson said...

No, cortisol may have caused a worsening of clinical signs but would not have caused development of a pituitary mass or large adrenal glands. The same timetable of events may have developed even if cortisol was never given.

There is no proof that Vetoryl accelerates tumor growth in the pituitary, especially in those dogs in which the cortisol values are not decreased to subnormal cortisol levels. In your dog, it doesn't look like the Vetoryl worked very well to lower the cortisol values, probably because of the large pituitary size.

Sharon Little said...

Dear Dr. Peterson,

I have a 7 yr old female spayed Scottie who shows no symptoms of Cushing's. She weighs 19.2 lbs' eats 3/4 cups jams mini chuncks daily and drinks about 1.5 cups water daily ( I measured it). She urinates 2 -3 times a day. Her coat has never been as thick as some other Scotties we have owned. But she has no bald or thin spots. She is flaky on her lower back above the tail but that is not new. She was on 0.5 pill of .1 mg soloxaine and gar tsh was 1.7. She was increased to 1 pill daily and retested 2/ months later when her tsh kevels were 1.7. My vet has been a Scottie breeder for over 20 years and is very interested in the breed. There was a study looking at increased alt levels but not Cushing's and we drew blood from my dog. Her alt and alkp were elevated. So we ran a cbc\chem screen and ACTH stim. Baseline coritsol was 2.4 ug\dl and after injection was 18.4ug\dl. Her alt was 227u\l, alkp 516u\l, alb 4.1 g\dl, bun 6 mg\ DL and Amy 442u\l.

My vet wants to start her on 30mg vetroyl. After reading the clinical trials I am do not have a good feeling about the safety. I did regulatory affairs for years with major pharm. Companies so I know a little about clinical trials.

I would feel better monitoring my dog for clinical symptoms and \or an increase of ACTH stim of 21ug\dl and than starting veyroyl.

What protocol do you use for treating borderline Cushing's?

Thank you for your time.

Dr. Mark E. Peterson said...

If a dog has no clinical signs of Cushing's, I don't treat unless they have significant hypertension or proteinuria that cannot be explained by anything else but Cushing's. I do not know what causes the high liver tests in this breed, but I don't think it is due to Cushing's in most dogs, at least not the classic disorder.

Bottom line: if this were my dog, I'd continue to monitor and not treat based on the results that you have provided.

Sharon Little said...

Thank you for your response. How often and with what test would you monitor? Would you start to treat when the ACTH stimulation test was 22ug \dl or above?

Thank you again

Dr. Mark E. Peterson said...

See this post -- there are many other tests that could be done to better define if your dog has Cushing's but these are generally done after clinical signs develop.

I don't treat numbers, I treat the dog-- in this case (Cushing's), trilostane isn't curing anything so why treat if there are no clinical signs? Talk to your vet or get a referral to a specialist.

Brenda said...

Dear Dr. Peterson,

Back in March 2015, my 8 ½ yr. old Bichon started drinking/urinating excessively and having accidents. Diagnosed & treated for urinary infection then two weeks later got diarrhea and treated for bacterial infection. Vet did full blood panel & with results suggested the LSSD test for Cushings. Test was done just 6 days after the antibiotic treatment started for the infection which she had not completed yet. LSSD came back positive: Base 8.83, 4 hr 9.76, 8 hr 15.0 – vet automatically wanted to start 30 mg Vetoryl but I got 2nd opinion just 3 weeks later & had ultrasound done which showed adrenal glands slightly enlarged. Other testing also indicated diabetes & pancreatitis so started insulin and changed food to Hills w/d. Glucose level was normal on prior tests in March; no testing for pancreatitis at that time.

Started with 5 units of Vetsulin twice a day in April and as soon as insulin was administered her drinking/urinating became normal and she was more restful at night. Went up to 9 units twice a day where she is now due to getting some numbers in 300 & 400’s (mostly 300’s & high 200’s). With the 9 units her levels on average dropped and she was getting good in range numbers on spot tests. That lasted 3 weeks and then her levels started going all over the place…some highs in 400’s and even 500’s (happened twice) but lows in low 100’s…very wide range on curves. Vet suggests this is due to Cushings and wants to start her on low dose of Vetoryl.

In reference to Cushings symptoms, I really don’t see that she has any, at least not the usual ones. She had a slightly distended belly but that seems to have gone down with the healing of the pancreatitis, had fungal/yeast skin infection which was cleared with a shot, but still has a few spots on her, fur is all in tact however undercoat has thinned and tail has thinned. Fur did grow back after shaving for ultrasound. No panting and drinking/urinating still normal in spite of the high glucose levels. Loves to eat but doesn’t beg for food.

Had her tested for hypothryroidism - had very low normal TSH and mid normal free T4 so negative.

Could these wide glucose ranges be caused by too much insulin(possibly now that pancreatitis is better)or do you think vet is correct in wanting to treat for Cushings? Should a lower dose or human insulin be tried before starting Cushing meds? Do you feel she even has Cushings since apparently she did have diabetes & pancreatitis at the time the Cushings test & ultrasound was done unless diabetes developed within an 18 day time span??

Thank you,

Dr. Mark E. Peterson said...

It is very difficult to diagnose Cushing's in a diabetic dog. We really need obvious hair loss, huge pot belly, or calcinosis to know for sure. But it sounds like the LDDST was done before the diabetes or pancreatitis developed so that could indicate Cushing's. Adrenal size by itself is not diagnostic, nor can normal adrenal size exclude the disease. So I cannot tell you if your dog has Cushing's or not.

Cushing's tends to cause insulin resistance and therefore raise the insulin requirements. It doesn't sound like that is what is going on with your dog at this time.

I'd recommend continuing to monitor, try to control diabetes as well as you can (some home glucose monitoring could be helpful), and repeating a LDDST or doing an ACTH stimulation test as you move forward. If Cushing's is present, the disease will progress and it will be easier to diagnose.

Treatment of diabetes alone or diabetes with Cushing's is always difficult and it can be next to impossible to get perfect regulation in these cases.

Brenda said...

Dr. Peterson,

Thank you for your extremely quick reply.

I do home testing which is how I know she's having such huge swings. I forgot to mention that she has lost almost 4 pounds since diagnosis. So, in your opinion then, at this time you don't feel Cushings is causing those swings and that she isn't showing insulin resistance? Do you feel we should try a lower dose or different insulin or food perhaps? Tonight I gave the insulin before her meal after seeing that is what you recommend and knowing that she always eats. Hoping it will have a positive impact.

Thank you again.

Dr. Mark E. Peterson said...

These dogs are complicated and I cannot help you with regulation. Sounds like you might be best off seeing an endocrine specialist. Everyone wants to blame diabetic problems on Cushing's but that's generally not the issue. Cushing's causes insulin resistance not swings in glucose levels and never hypoglycemia.

broddybounce said...

Hi Dr. Peterson,

A few weeks back I sent you a message here, but never received a response and I figured you were extremely busy at that time; but now I'm also wondering if, somehow, you may have not received it.

I thought I'd follow up to make sure you had received it -- it was a question about my dog, 15yo, newly diagnosed Cushing's. Three years ago she was tested via LDDS which came up negative for Cushing's -- but she had developed hypothyroidism, and, by process of deduction after other multiple tests, we relegated her PU/PD to diabetes insipidus.

But with this late diagnosis of Cushing's, coincidentally (or not coincidentally), instead of developing classic "ravenous appetite" symptom, became increasingly anorexic while, at the same time presented increased diarrhea, sometimes of varying colors, but no UTI.

At the same time, other Cushing's symptoms presented themselves full force such as sudden increased onset of PU/PD, despite the successful use of desmopressin (ocular) for the previous three years, and hind-leg weakness.

We ran all kinds of tests including ultrasound, CT scans and multiple blood panels. There was no pituitary macroadenoma, no adrenal tumor (although classic enlargement of both glands as per Cushing's), no pancreatitis, and GI tract presented no major abnormalities, such as obstruction. However, there was increased ALT, ALP, GGT.

A late x-ray did present a tumor on the lung. We did not biopsy so did not know with 100% certainty if it was cancer, which she did have twice before in other locations or, very remotely, a foxtail, but which, if had been inhaled, had occurred a full three months prior with no symptoms presenting.

Vet felt it was the malignant tumor metastasizing and causing the atypical-to-Cushing's anorexia, but that has not been confirmed.

My question to you, however: have you ever been presented a case where subject has Cushing's but displays anorexia?

As you may have read into this, unfortunately, I decided upon euthanasia a couple of weeks ago right after the lung tumor diagnosis because she appeared to be in much pain over the last many days and, with not much to go on to relieve her symptoms other than more major testing, possibly surgery, and possibly RT at nearby UC Davis, I didn't want to put her through all that at 15yo.

Indeed, this is now "post-mortem," but would love to hear any thoughts you have -- and if you need any additional information, let me know.



Dr. Mark E. Peterson said...

Dogs with Cushing's disease alone will never be anorexic. But your dog had other problems which could explain the lack of appetite. Overall, the prognosis was very grave and you made the right decision, at least in my opinion.

broddybounce said...

Your review of my case as I had presented it and your subsequent conclusion are helpful, validating and very much appreciated. Thank you.

Dr. Mark E. Peterson said...

You are welcome...

Radhika Kohli said...

Hi Dr,
My dog is and 11 year old border collie/black lab mix. Earlier this year she seemed fine, but in the past months she has had urinary issues (leaking) but in the past few months has had excessive weight gain (20 pounds), pot belly, looks very swollen, odd hair growth (patches). We are told she has cushings, but are waiting for the results. Is this treatable? Once she starts taking the correct medication will her weight go down to normal and will she grow hair normally and will the heavy breathing reduce?? Please let me know, I'm very worried.

Dr. Mark E. Peterson said...

This is a common medical disease and is generally can be managed very well. Talk to your vet.

Brenda said...

Hello Dr. Peterson,

My vet wants my diabetic dog to get a ACTH Stim test which is scheduled for this week. She's been diabetic for a year but last year did have the LDDST also which did indicate Cushings. Chose not to treat her as I don't see normal symptoms. What she does have are brown/black spots on skin which my vet says is an overproduction of oil from skin glands (is this a symptom?), thinning fur on tail and, most of all BG numbers all over the place. I had written you last year about her BG numbers and you indicated if they get lows into 100's then Cushings would not be in play but my vet says this true? My concern with the test is since she has to eat & have insulin my vet said to have her fast (taking senior blood panel as well) then after he does initial blood draw & give solution for test he's going to feed her & give insulin. Will doing this affect the result of the ACTH? Thank you,Brenda

Dr. Mark E. Peterson said...

No, this protocol will not affect the ACTH stimulation test.

Brenda said...

Thank you Dr. Can you please also let me know if Cushings could cause the excess oil on her skin? If no other symptoms should she be treated for Cushings to see if it helps her BG numbers?

Dr. Mark E. Peterson said...

Cushing's dogs certainly have skin problems but "excess oil on the skin" isn't one that I hear about so I do not know (not specific anyway). Dogs with Cushing's can develop severe insulin resistance and require large doses of insulin. That's the only time that treatment of Cushing's will help control diabetes, by lowering the doses of insulin.

You might want to get another opinion from a speciality about how to best care for your dog.

tessa rogers said...

Hello Dr Peterson.
I have a 6yo Beagle bitch who developed anorexia last week and I took her to our vet. Bloods showed a high ALP and very dilute urine. No fevers, no abdominal pain.
She has also had excess drinking, urinating, and she also pants alot. We put it down to hot Australian summers. We have noticed this over maybe 2yrs.

She is always hungry( but she is a beagle) and has always eaten her own and our others dogs poo. She also gets up most nights with a very grumbly sounding tummy and goes out side to eat grass.

Our vet is planning to to an ATCH blood test and Abdo USS next week.

Do you think these other symptoms are also consistent with Cushings in your experience or are they more likely to be something as well as or different?

The anorexia has since passed and she seems back to normal at the moment.

Many thanks,

Dr. Mark E. Peterson said...

Anorexia is NOT a sign of Cushing's. So if that's why you took her to the vet, I'd not do any more tests now but just follow the liver test in 3-6 months