Dog Recently Diagnosed with Cushing's

[lmg121]

Hi All,
My dog Boo was diagnosed with pituitary-dependent Cushing's last week. He is a 13 year old male maltese/shih tzu mix. A couple of weeks ago, he woke up in the middle of the night crying/screeching with his back arched and muscles tense. This lasted only about thirty seconds. By the time I turned on the light, this episode was over. He had urinated on himself and did not move from where he was on the bed. We went to the emergency vet and they did blood work, and EKG, and a urinalysis. The blood work showed his platelet count was very high. His urinalysis and EKG were normal. The vet also did an ultrasound on his adrenal glands. He found that the adrenal glands were enlarged with one having some nodes and the other having some crystallization. For a few days following his episode, his back legs were shaky.

After this, he underwent the low dose dexamethasone suppression test. Pre-test he was at 4.3. Post 4 hr was .5 and Post 8 hr was 1.7. Because he underwent a possible neurological event, they did an MRI of his brain which did not show a macroadenoma but did show some mild hydrocephalus and some atrophy due to his age.
Prior to his neurological episode I noticed the following symptoms, increased urination and thirst and slight increase in appetite.

The vet wants to start him on 6mg of Vetoryl per day. I'm wondering what your thoughts are regarding this and if there is anything I should be concerned about/ ask the vet.

Thank you in advance for all of your help!

[lmg121]

A little background on his prior medical history. He had hip surgery when he was 4 after being hit by a car and went blind when he was five for unknown reasons. He also suffers from separation anxiety. Following his neurological episode, he was completely listless for about twenty-five minutes.

[labblab]

Hello and welcome to you and Boo. I am very sorry, though, for the problems that have brought you to us. I have a non-Cushing's dog who suffers from a seizure disorder, so I know how scary these neurological episodes can be. At this point, I'm assuming the vets are taking a wait-and-see approach re: whether or not the episode repeats?

As for the Cushing's, can you please give us the "normal" range for Boo's LDDS test? I am guessing it was either 1.4 or 1.5. If so, his eight-hour result was higher than normal and therefore technically "positive" for Cushing's, but only a bit out of range. If Boo indeed has Cushing's, an interesting aspect of the test is that it is consistent with the pituitary form of the disease. The MRI did not reveal a large macrotumor, but did it reveal a pituitary tumor at all? Given the report that "nodes" were imaged on the adrenal ultrasound, do the vets think an adrenal tumor may be present in addition/instead?

The reason why I am wondering about the vets' interpretation of all this is because issues other than Cushing's can result in similar overt symptoms (thirst/urination, etc.), elevated LDDS results, and also adrenal gland enlargement. Since Boo did have an MRI, I would think a pituitary tumor should have been seen if it is indeed present. If there is neither a pituitary nor adrenal tumor seen on imaging, I would be wondering whether Cushing's is really the culprit, or whether there is some other systemic issue at play that also caused the neurological episode.

However, if your vets are confident about the Cushing's diagnosis and you proceed with treatment with trilostane, you will want to start at a dose that does not exceed 1mg. per pound. So the appropriateness of the 6 mg. dosage will depend upon Boo's weight.

Marianne

[molly muffin]

Hello and welcome to the forum. Did they think the seizure could be related to something else other than cushings and consider medication for them if they continue?

Also did they check his electrolytes just to be careful, as they can cause seizures too.

Marianne is right, no more than 1mg per lb for medication and I think since his results are only minimally elevated that they might want to start even lower.

Welcome to the forum

[lmg121]

Thank you both for your advice. I got his official MRI results from the vet today and he said that it was pretty normal other than the mild hydrocephalus which he has probably had since he was a puppy. The reference range for the cushing's test was 1.5. I asked the vet if since the seizure like event was not related to a macroadenoma, is it worth treating since his only real symptom is increased water intake, and the vet said that unless it was a problem for me, there is no need to treat. At this point, I'm going to take a wait and see approach since Boo is not in distress.

I really appreciate your help and am so glad this forum is here to help me navigate all of these tests and vet appointments!

[labblab]

Hmmm...here is where I am confused. If there is no evidence of either a pituitary tumor on the MRI nor an adrenal tumor on the ultrasound, then Boo cannot have Cushing's. Most pituitary tumors are not large enough to be classified as macroadenomas, but I still would have expected the MRI to reveal a tumor if one was present.

Can you ask your vet if there was a pituitary tumor on the MRI? If not, does he think there is an adrenal tumor present? One or the other has to exist in order to cause Cushing's. The only other option is if a dog is receiving supplemental steroids, and in that case, the Cushing's symptoms resolve if the steroid is simply discontinued.

Marianne