Lennox (Boxer boy) - Newly diagnosed w/ Cushing's, CC, seizure - Treatment?

[WibblesLee]

Hello all,

It's been quite enlightening to read all of the responses regarding Cushing's and how Calcinosis Cutis relates. My boxer, Lennox, has recently been diagnosed with Cushing's (his symptoms include excessive drinking and urination, muscle wasting, hair loss, 'pot-bellied' appearance and most recently CC). We do not know exactly how old Lennox is, as we adopted him from a rescue that ceased him from a puppy mill, but we think he's somewhere between 8 and 11.

Not quite two weeks ago, Lennox had a twelve minute long seizure at 4am (thank God I woke up when it began), and we have since put him on a very low dose of Phenobarbital. Our veterinarian is hesitant to treat Lennox for the Cushing's symptoms because of his risk for seizures and the interactions that the Cushing's medication could have with the Phenobarbital.

At this point, my partner and I are at a loss for what the best steps would be for Lennox. I desperately want him to have the best life possible, but I don't know if he is still enjoying life? Although he seems happy when we have snuggle time together, he does not want to go for walks as much as he used to (to be fair, we've had an extremely harsh winter and he does not like snow very much) and spends most of his time sleeping.

Basically, I was just hoping to hear from some other fur-parents who have an understanding of what it's like to have a fur-baby with Cushing's. As much as our vet is able to offer some advice from a medical stand point (we really have lucked out with a wonderful vet), it's always so much more helpful to hear from others who are going through the same thing.

Thanks in advance for any thoughts or suggestions. I am terribly sorry to hear that Peety has moved on to the big doggy park in the sky - he sounded like a wonderful little guy.

[labblab]

Hello and welcome to you and Lennox. You will see that I have taken the liberty of shifting your reply from Peety's thread where you originally posted, and I instead shifted it here to create a new thread that is your very own. This way, it will be much easier for our members to reply to you directly. :)

I apologize for launching into a number of questions, but your answers will help guide us from this point forward. First, can you tell us exactly what testing was done to confirm the Cushing's diagnosis in general, and also the calcinosis cutis? It is our understanding that the CC requires an actual lesion biopsy for confirmation. If Lennox truly has CC, then effective Cushing's treatment may be even a higher priority for you due to the very serious "quality of life" issues that arise with uncontrolled skin involvement.

Shifting for a moment to the seizure, are there any laboratory abnormalities at all that could point towards a cause? How about Lennox's thyroid function? Cushpups frequently experience lowered thyroid function as a secondary result of the disease. For many dogs, no thyroid treatment is necessary because the thyroid issue will resolve once the Cushing's is controlled. But seizures are associated with low thyroid levels, so if Lennox is suffering from either primary or secondary thyroid dysfunction, that might be the cause.

As awful as it must have been for you to witness the seizure, I am a bit surprised that the vet has started Lennox on phenobarb after only a single episode [Editing note: Please see my subsequent reply in which I have a better understanding as to why treatment is started after a single, lengthy seizure]. I have now been treating my non-Cushing's labrador with phenobarb for three years due to grand mal seizures of unknown origin. Most of the things I read when we started treatment ourselves suggested that it is not rare for dogs to experience a single seizure at some point in their lifetime, and that given the serious effects of the anti-convulsive medication, you would want to wait to start treating until you were assured that there was a pattern emerging that justified the need. My own dog had four seizures over a two-month period, and that's when we started the phenobarb.

Also, I am not exactly sure what "low dose" phenobarb means. There is a specific therapeutic range that must be achieved and monitored via blood analysis. If your vet is not aiming to reach that therapeutic range, then it seems to me that there is little point in risking ill effects from the phenobarb if the dose is too low to actually prevent additional seizures.

It is true that phenobarb is not an ideal combination with Cushing's meds. But that is not to say that it can't be done. Also, there are newer generation anti-convulsants that may not interact in the same way, if Lennox truly does need seizure medication. And if he has indeed been diagnosed with calcinosis cutis, I do believe his Cushing's treatment will be equally as high a priority for you.

So bottom line, please do get back with us and tell us more about all the diagnostic testing, OK?

Thanks so much!
Marianne

[labblab]

I do want to mention one other possibility -- not to alarm you unnecessarily, but just so you will not be surprised if you read this elsewhere. From what you have written so far, we do not know whether Lennox's Cushing's testing has pointed towards a pituitary vs. an adrenal tumor. But if he does have a pituitary tumor, sometimes those tumors can expand to the extent that they place pressure on other areas of the brain, causing neurological problems. Seizures are not the most common symptoms of this type of encroachment, but they can occur. If, by chance, Lennox does have a pituitary "macrotumor," this creates a whole additional host of treatment questions.

So once again, depending on the additional info you can give us, your treatment choices may vary considerably. By any chance, do you know if there are any specialized veterinary practices near you with whom you or your vet might consult? It sounds as though Lennox's situation is complicated enough that some additional input on the front end may be very helpful to you in the long run.

Marianne

[Renee]

Popping into second everything Marianne said, especially in regards to the dreaded CC and the phenobarb treatment!

[WibblesLee]

Hi Marianne,

After reading many other posts last night, I anticipated these types of questions! However, I don't have many answers.

Initially, Lennox began drinking excessive amounts of water around Christmas time, and quite quickly (a matter of 24-48 hours) began urinating inside. Due to Lennox being a rescue dog, we had battled with his inappropriate urination before, but it became very obvious that something more was happening when this became an occurrence between 3-8 times a day. Lennox was also losing weight rapidly, however we thought that perhaps that may have been because we switched him from Blue Buffalo's Wilderness formula to Blue Buffalo's Wilderness Senior formula (he was becoming quite chubby). He also appeared to be losing hair (around his neck which we thought might be from his collar, however after taking the collar off for a few days the hair loss still proceeded; on the insides of this legs; and on his stomach), and his skin was quite red and thin.

We took Lennox to the vet with the thought that perhaps Diabetes or a Thyroid issue might be the culprit, and the vet ran blood tests (unfortunately, I do not know exactly WHAT tests he ran). We received a call the next day, and the vet indicated that Lennox's red blood cell count was high (I do not know the normal range) and that it was also noted that he was producing new red blood cells. The vet asked me to keep an eye on Lennox, continue to give him as much fresh water as possible, and to bring Lennox back in a month's time to do another blood test. He also indicated that he had a feeling that Lennox might be suffering from Cushing's based on a number of the symptoms he was displaying, but that we would address that possibility when we brought him back for the next blood test.

Lennox had his seizure in the early hours of the morning that we were scheduled to take him in for his deximethozone suppression test, so upon arrival at the vet's office (after talking to the emergency team during his seizure and deciding that as long as he did not have another one, we should wait to bring him in at his scheduled time of 8:30am) our vet concluded that if Lennox was his own dog, he would not even put him through the deximethozone test because if indeed Cushing's was causing too much cortizol to be produced, the cortizol would act as an anti-inflammatory and help reduce any swelling around the brain that could have caused the seizure.

Having no experience with seizures or with Cushing's, I took my vet's advice and we did not proceed with the testing for Cushing's. Instead, my vet prescribed Lennox 60mg of Phenobarbital a day, to be taken in 30mg doses every twelve hours. He wanted to begin with this to see how Lennox would react, and we planned to increase the dosage to 120mg a day if Lennox adjusted well. He also gave me an emergency pack in case Lennox seized again and it lasted longer than 5 minutes (since the first seizure lasted 12 minutes). The emergency pack contains 6 10mg vials of Diazapam (valium), 3 of which are to be administered rectally if a seizure occurs for longer than 5 minutes. This SHOULD halt the seizure, but if not, another 3 vials can be administered.

Luckily, Lennox has not seized since. I called the vet a week later, as instructed, and he recommended that if Lennox was not having any other seizures (which he has not) that we should remain with the subtherapeutic level that we are giving him (30mg twice a day for a total of 60mg of Phenobarbital). I asked the vet about whether or not we should be treating the Cushing's symptoms because realistically, how long can a dog go on experiencing the kind of muscle wasting that he is, and he recommended that we go another month monitoring Lennox's situation, and then re-evaluate. That was last week, so we are currently running along at the rate of 60mg of Pheno a day with no treatment of the Cushing's symptoms.

As for the Calcinosis Cutis, he had only started to develop flaky skin when we saw the vet two weeks ago after Lennox's seizure. This has since developed into a cluster of lesions that run along Lennox's spine area starting approximately where his shoulders are and ending around the top of where his ribcage begins (I think?). Lennox has always had strange skin issues (numerous skin tags that develop constantly, a weird boil on his left hind leg that does not bother him at all, dry-ish skin), so at first I thought nothing of this development. However, the rate at which it has progressed in the past two weeks is quite alarming. Lennox is also losing his hair around the lesion sites. I decided to do some digging yesterday on Google regarding the treatment of Cushing's, and ended up coming across a website that FINALLY described Calcinosis Cutis as a symptom of Cushing's. I then ran a Google image search of exactly what calcium buildup on the skin of a dog would look like, and sure enough, the results that were turned up look EXACTLY like the lesions that have formed on Lennox. I have not had a biopsy done on Lennox yet, as it was only yesterday that I made this discovery, but I am 99% sure (call it Mother's intuition?) that it is indeed CC that Lennox has started to suffer from most recently.

Hopefully that novel I've just written you, Marianne, will help. I'm sorry for the lack of specifics when it comes to what testing Lennox has had, he is the first dog I have owned in my adult life, and to be honest, I'm not sure I thought to ask all of the right questions when talking out our vet.

Thank you in advance to everyone for kind words and wisdom. It's greatly appreciated.

~Whitney (and Lennox - he's currently snoozing at my feet and snoring incredibly loudly).

[labblab]

Dear Whitney,

Thank you so much for such a detailed reply! Some questions have been answered; others remain. But you've given us a great starting point :). First of all, I can only imagine how freaked out you must have been by a ten-minute seizure. If it was a grand mal seizure, that is a really long time to be watching your dog struggling so, and I do understand that is a dangerously long time for a seizure to continue and you don't want to see it repeated. Secondly, I want to caution you that I am not a vet, so all of my comments that follow are strictly my personal thoughts. But you have told us a few things that have raised even more question marks for me. So these are the things I am wondering about...



Initially, Lennox began drinking excessive amounts of water around Christmas time, and quite quickly (a matter of 24-48 hours) began urinating inside. Due to Lennox being a rescue dog, we had battled with his inappropriate urination before, but it became very obvious that something more was happening when this became an occurrence between 3-8 times a day. Lennox was also losing weight rapidly, however we thought that perhaps that may have been because we switched him from Blue Buffalo's Wilderness formula to Blue Buffalo's Wilderness Senior formula (he was becoming quite chubby).
The onset of Cushing's is typically a gradual process of slowly worsening symptoms. We do not usually see the sudden, acute development of excessive thirst/urination over a brief period of 1-2 days. Further, most Cushpups gain weight rather than losing it. My own Cushpup is an exception -- he did slowly lose weight over time. However, again, you are describing a "rapid" change in weight that is inconsistent with most Cushing's cases we experience here.



We took Lennox to the vet with the thought that perhaps Diabetes or a Thyroid issue might be the culprit, and the vet ran blood tests (unfortunately, I do not know exactly WHAT tests he ran). We received a call the next day, and the vet indicated that Lennox's red blood cell count was high (I do not know the normal range) and that it was also noted that he was producing new red blood cells. The vet asked me to keep an eye on Lennox, continue to give him as much fresh water as possible, and to bring Lennox back in a month's time to do another blood test.
Has Lennox's red count remained high? Does the vet have any explanation for this abnormality? I know that dehydration can lead to elevated red cell counts on lab results, but you've also noted that Lennox may be producing abnormally high numbers of new blood cells. If there is a pathological basis for the abnormal red cell counts, I am thinking this could be related to his seizure since metabolic problems that are known to cause seizures include low blood sugar, low calcium, and elevated red blood cell production.



Lennox had his seizure in the early hours of the morning that we were scheduled to take him in for his deximethozone suppression test, so upon arrival at the vet's office (after talking to the emergency team during his seizure and deciding that as long as he did not have another one, we should wait to bring him in at his scheduled time of 8:30am) our vet concluded that if Lennox was his own dog, he would not even put him through the deximethozone test because if indeed Cushing's was causing too much cortizol to be produced, the cortizol would act as an anti-inflammatory and help reduce any swelling around the brain that could have caused the seizure.
It is very wise that your vet did not proceed with the low dose dex test right at that moment, because the results of that test can be totally skewed in the face of anxiety or other nonadrenal illness. There is no way in which the results of a low dose test performed within hours after a seizure would likely be an accurate indicator of Cushing's. However, if Lennox does truly suffer from Cushing's, I don't know why you would never consider testing nor treatment to lower cortisol in the absence of having identified the true cause for the seizure. As stated above, there can be metabolic causes for seizures that have no relation to brain swelling and no need for anti-inflammatory action.


Having no experience with seizures or with Cushing's, I took my vet's advice and we did not proceed with the testing for Cushing's. Instead, my vet prescribed Lennox 60mg of Phenobarbital a day, to be taken in 30mg doses every twelve hours. He wanted to begin with this to see how Lennox would react, and we planned to increase the dosage to 120mg a day if Lennox adjusted well...

...Luckily, Lennox has not seized since. I called the vet a week later, as instructed, and he recommended that if Lennox was not having any other seizures (which he has not) that we should remain with the subtherapeutic level that we are giving him (30mg twice a day for a total of 60mg of Phenobarbital).

The typical starting dose for phenobarb is 2.5 - 3.0 mg. per kilogram given every twelve hours. Not knowing how much Lennox weighs, I cannot judge where his current dose falls within that range. But no matter what dose is given, I would expect that your vet would be advising you to follow standard protocol which is to test the level of the phenobarb in Lennox's bloodstream within one month of starting the drug to make sure that the level is neither too high to be toxic nor too low to miss protecting him against future seizures. I am not an expert on phenobarb by any means. But I personally have not heard anyone purposely aiming at "subtherapeutic" doses of the drug at an early stage of treatment when you are trying to achieve stabilization. Again, I just don't see the point of risking liver damage or side effects if you aren't getting adequate protection against future seizures.

In summary, based on your initial description of the acute onset of h is symptoms, I am really questioning whether Cushing's is the source of Lennox's problems. However, one wild card here is the possible calcinosis cutis. In conjunction with the symptoms you've described, a confirmed diagnosis of CC would definitely tip the scales towards Cushing's. If Lennox does truly have Cushing's, then I'd really question your vet's recommendation to ignore Cushing's testing and treatment in the absence of a known cause for the seizure. Depending upon the cause of the seizure, elevated cortisol might be helpful or it might not be helpful at all, and at the expense of controlling any genuine Cushing's symptoms.

Marianne

[labblab]

It's me, back again! Ever since your first post, I've been trying to read up some more on seizure treatment (which will hopefully benefit my own Peg, as well!). I do see that a single long-lasting seizure (over 5 minutes) is thought by others to be reason, in and of itself, to start anticonvulsant therapy immediately. The worry is that seizures of that duration have the potential to actually cause brain damage, and you don't want them to be repeated. So this info does support your vet's decision to move forward right away, and I wanted to clarify any confusion I may have created in that regard.

I'm still trying to find more info about "subtherapeutic" dosing... I've found a study that addresses the possibility of allowing human patients to maintain on lower levels once they have been stabilized and seizure-free for three months or more, but so far nothing about starting out at lower levels from the get-go. I'll keep looking, though.

Marianne

[WibblesLee]

Hi Marianne,

Thanks so much for all of your feedback, it's greatly appreciated! Last night was not a great night for Lennox - although he didn't have any in-house accidents, we were up almost ever hour on the hour to go outside, get a drink and have a snack. I've started feeding him whenever he is hungry as opposed to just a couple of times a day and good God, he's eating probably 5-6 cups of food a day!

I think I will get our vet a call sometime this week, because in all honesty, I can't keep going like this. It's like having a newborn in the house, except I'm still going to work every day! Hopefully we can get a dex. suppression test done and perhaps a biopsy for the CC to figure out what in the heck is going on. I just want to get Lennox back to his normal self - I know it's later on in his life, but I'm worried that if we don't find out the cause of these issues there won't be much more of his life left.

I'm also hoping that the weather will remain half decent so that we can start going out for walks again. We're actually moving next week to a property that has 2.5 acres and I think Lennox will really enjoy this if we can get him feeling normal!

Thank you again for all of your wisdom and support. I'll keep you updated with my discussion with the vet!

[pansywags]

I'm so sorry to hear about Lennox's troubles. My boxer girl has Cushings and I can totally sympathize with your distress regarding the incontinence. We are managing this right now with a complicated system of open doors during the day and night barricades with a lot of urine pads to protect the rugs. As a boxer owner you'll understand the terrible downside to this - it's really a hardship to separate a boxer from their people, and it makes me so sad to close the door on Pansy's sweet mug every night.

A 12 minute seizure, wow. Can you describe what happened during that time?

I encourage you to get copies of all the tests run on your dog and post them here, and keep a good set of records for yourself. I got better information from the people here than I did from my vet AND a local internal medicine specialist vet. Cushing's can be complicated to diagnose and treat. I think I saw you are posting from Ontario - I wonder if the Ontario Veterinary College at the University of Guelph might have vets with experience treating Cushing's?

[labblab]

You probably already know this, but a double whammy for you is that phenobarb itself can cause many Cushing's-like side effects, especially during the first few weeks of treatment until the dog has a chance to adjust. So this may be a reason why your vet is trying to walk a tightrope and keep the phenobarb dosing at a bare minimum.

My own Peg looked and acted just like my Cushpup Barkis when she first started on phenobarb :o. Excessive thirst and urination, lethargy, etc. (I can't speak to excessive hunger because all my Labs have always had ravenous appetites, Cuishing's or no Cushing's!!). But excessive hunger is also a phenobarb symptom.

We have been very lucky with Peg in that the phenobarb has totally controlled her seizures and most all of the drug side effects resolved after the first month or so. But I would have to suppose that poor Lennox is getting some additive symptoms from the phenobarb, even at a lower dose. :(

Marianne

[WibblesLee]

Pansy! What a BEAUTIFUL Boxer! She reminds me of Lennox so much just by looking at her sweet face :)

As for the seizure, I woke up at 4am because I heard Lennox scrambling in his crate as if he was trying to get up but slipping. And then, out of no where, he started snoring. I was like 'What on Earth? That doesn't make sense... maybe he's dreaming', but got up to check anyway. When I got out to the living room (just the other side of the wall from my bedroom) and turned on the lights, Lennox was flopped on his side in the crate with his legs sticking straight out, jerking back and forth. His jaw had locked and his tongue was stuck out (trapped in his mouth - luckily, he has very few teeth due to his mistreatment in the puppy mill, so he did not puncture or sever his tongue). He was 'snoring', with his eyes open and bulging slightly, and was foaming at the mouth. At this point, I called Andrew (my fiance) out from the bedroom (the man could sleep through a bloody hurricane) and he advised me to keep my hands away from Lennox's face (although all I wanted to do was hold him and tell him it would be ok). I called the emergency vet (at this point it was about 5 minutes into the seizure from what I could tell) who told me to continue to monitor Lennox, who was still seizing at this point. Due to this being his first seizure, the vet wanted to stay on the phone to see how long it would last and at around the 12 minute mark he started to come out of it - his eyes became alert as opposed to glazed over, his extremities softened and he could move them independently, and his jaw FINALLY unlocked (this was still maybe 5-7 minutes after the rest of him started to normalize). The emerg. vet told me to monitor him for the rest of the morning and that if he started to seize again, to bring him in immediately, otherwise just to wait until our previously scheduled appointment with our regular vet at 8:30am.

Thankfully, it was an uneventful morning from then on, although Lennox was not able to stand up again until just after 6am. At that point, although he was able to stand he was extremely disoriented, walked into objects, walked in circles and even fell head first into the floor. I was absolutely horrified and heartbroken watching him like this, and he was very agitated on top of it all, so it was impossible to get him to lie down and stay in one place. He had difficulty drinking from his water dish, so I had to hold it up to his head to allow him to drink out of it. By the time we took him into the vet's at 8:30am, he was walking a little more steadily, although still circled often and was still quite wobbly. It was not until almost a full 24 hours later that he really seemed to be back to normal.

So that was the seizure experience! :(

As for Lennox's excessive hunger - he has always been a ravenous eater as well, however he would hoover up his normal amount of food and then that was it. It's to the point now, that if he does not have food in his bowl and he thinks he should, he will whine and 'silent howl' (it looks like he's howling, but no sound comes out - actually kind of hilarious) until we feed him. I figure it can't do him any harm, the poor thing is skin and bones now. He used to be approximately 75lbs and has since become 60lbs over the past few months (December-ish to now). It does, however, become a real frustration when he feel like he needs food at 1am, 2am, 3am, 4:30am, 6am etc. So needless to say, between him needing to go out to go pee and insisting upon having a snack, I'm not getting much sleep!

Hopefully I'll have some results from my vet as to what tests were performed originally, and I will definitely post the results on here as soon as I do. I will also try and get normal ranges to compare to when I get the results. I'm hoping maybe they can fax them to me at work, rather than me trying to get into the office to pick them up.

Thanks again for the input everyone! It's greatly appreciated! :D

[molly muffin]

Hi Whitney and Lennox,

I understand what your vet is thinking with the cortisol being higher acts as an antiinflammatory and if he is thinking this is a macro tumor of the pituitary gland, then treating for cushings can cause it to grow and cause more problems, like the seizures. So, that might be what your vet is thinking.

Were any other blood tests done to rule out other possibilities? thyroid for instance, diabetes, etc? I'd want a full blood work, and urinalysis to be done to see what can be ruled out prior to the LDDS being done.

You could ask him if that is what he is thinking too. (a macro) Yes cc is a sign of cushings and boxers are prone to cushings and to macro tumors unfortunately. I think due to the shape of their heads, it puts a lot of pressure on different things when they grow.

I'm so glad you found us and sorry it has taken me so long to see your thread and welcome you to the group. Marianne though honestly has the most experience with phenobarb so I'm very glad she saw your thread and has been able to give you some help in that aspect. (she has a lot of experience with cushings too as she has been down both roads, seizures and cushings.

again welcome
sharlene and molly muffin

[WibblesLee]

Hello Molly Muffin and Sharlene!

Sorry it has taken me so long to reply - it's been a very busy week here. I spoke to our vet and yes, his gut feeling is that Lennox has a macro, hence his being hesitant to treat the Cushing's symptoms. At this rate, however, we need to either start treating the Cushing's symptoms (Lennox is growing skinnier by the day) or try and figure out an alternative. I will be going into the vet tomorrow afternoon hopefully (I have to be in that area anyway) to discuss what the next steps should be.

I know that originally we had scheduled Lennox for a low-dose dex. suppression test to try and make a positive Cushing's diagnosis, however I hear a lot of talk about ACTH tests on here. Is this preferred over the low-dose dex. suppression test? Why would a vet opt to do one over the other? Any input is appreciated. My vet does not prefer to do ultrasounds due to their cost, so I don't think that is a route we will be going unless there is a huge benefit to it.

Thanks to everyone for their input, it's greatly appreciated!

Lots of love from myself and from Lennox (currently snoozing by my feet - only snoring a moderate amount for once).

[Renee]

As far as diagnosis goes, we did both an ACTH and LDDS test. The ACTH is talked about quite a bit, because it is used for monitoring during treatment. It is not relied on as a single diagnostic tool, due to the chance of false positives.

[molly muffin]

Is the pheno controling the seizures? None since starting?

Often they do both ACTH and LDDS to accurately diagnosis for cushing. The LDDS can often determine between pituitary and adrenal types of cushings. The ACTH will tell you if the cortisol levels are high or not. It will also be elevated though if anything else is going on. With Red Blood cells high and making more, I would suspect that the cortisol would be high.

I'm glad that you are discussing next options with your vet. He does seem to realize the problems that come along with treating for cushings if it is a macro, which I would hope makes him aware also of cushings and medicine options. I'm hopeful that he will have an idea for a plan to move forward with, but be aware that IF it is macro, then there may not be many viable options. However, if it is something else causing the seizures and the pheno is controling the seizures and there is not other neurological symptoms, then it might be.

I know that isn't very helpful probably, but this is not an easy disease to either diagnose or to always work out the dynamics of.

Sharlene and molly muffin

[labblab]

You've asked about advantages/disadvantages to the LDDS and ACTH as diagnostic tests. As others have already said, the ACTH is the only one of the two to be used for monitoring purposes once drug treatment is started. However, either of the tests can be used to initially diagnose Cushing's -- each with it's own pros-and-cons. The ACTH is a more "specific" test for Cushing's; the LDDS is a more "sensitive" test for Cushing's. I'll try to explain what that means below.

As Sharlene has said, one benefit of the LDDS is that, depending on the numerical result, the test can point to the pituitary rather than the adrenal form of the disease. The ACTH cannot do that. On the other hand, the ACTH is less likely to return a "false positive" if a dog is suffering from a different illness other than Cushing's. So for a dog with questionable symptoms for whom you'd prefer to err on the side of caution before beginning treatment, the ACTH may be the preferable test. The downside, though, is that the ACTH is more likely to return a normal result even if a dog truly does have Cushing's. So the ACTH is the more "specific" test (less likely to give a false positive), while the LDDS is the more "sensitive" test (less likely to give a false negative). Confusing enough?? :o

For what it's worth, here's a decision-making chart that I've always found helpful in deciding which test to start off with. It is a set of testing recommendations given by Dr. Rhett Nichols (http://www.k9cushings.com/forum/showthread.php?t=210):


Final screening recommendations

What if the patient has only biochemical changes and no or mild clinical signs suggestive of Cushing’s syndrome?
The ACTH response test may be the preferred test. In these patients, it may be better to miss a diagnosis of HAC [Cushing's] in early stages by using a test with lower sensitivity than falsely diagnose HAC by using a test with lower specificity.

Is nonadrenal illness present?
The LDDS and ACTH response tests can give false positive results in the face of nonadrenal illness, but the LDDST is more likely to do so. Thus, the ACTH response test is recommended when nonadrenal illness is present.

What if the patient has moderate to severe clinical signs of HAC and has no known nonadrenal illness?
The LDDST is preferred as the initial screening test. This test has a higher sensitivity as compared to the ACTH response test.

Is an AT [adrenal tumor] suspected?
The LDDST is recommended because the sensitivity of the ACTH response test for HAC caused by an AT is only 62%.

Has the Cushing’s syndrome suspect been treated with a cortisone
preparation?
The ACTH response test is the preferred test if an animal has a definitive or questionable history of receiving exogenouscorticosteroids and has signs compatible with HAC...

Marianne

[Squirt's Mom]

My vet does not prefer to do ultrasounds due to their cost, so I don't think that is a route we will be going unless there is a huge benefit to it.

In my experience, the ultrasound is THE most valuable test we have at our disposal. The ultrasounds during the diagnostic phase for Squirt saved her life by finding a tumor on her spleen. All her tests to that point had been positive for PDH - the LDDS, HDDS, ACTH, and UTK panel. But once the tumor and half her spleen were removed, her cortisol returned to normal. The tumor was the cause for the elevated cortisol.

Today, I couldn't afford to have all the testing done I did at that time but if I had to choose, it would be the ACTH and the ultrasound. Yes, the US is expensive but it gives the biggest bang for your money of all those tests not only because it can go a long way toward diagnosis and determining which type, but because it allows them to get a look at many organs.

I am not suggesting Lennox have an US - you have your immediate battle in front of you now with the seizures. But neither did I want you, or anyone else, to think this test doesn't have great value for our cush babies. ;)

There isn't anything I can offer you and Lennox other than my prayers, positive thoughts and healing energies. You have those in spades.
Hugs,
Leslie and the gang

[goldengirl88]

All I can add to what has already been said, the ultrasound turned out to be the most important tool for my Tipper. I would not know she has both a pituitary and adrenal tumor without it. My heart goes out to you for dealing with the thought of this being a macro. This is not easy by any means, and I pray from the best for you and Lennox. Blessings
Patti

[pansywags]

I'm glad your vet understands the risk of treating a potential macro medically. Ultrasound is expensive, but I felt it was worth it in Pansy's case because boxers are extremely prone to a wide variety of cancers, and if there was something else life-limiting going on with her internal organs, that would have a huge bearing on my decision of whether to treat, given that we seem to be moving toward a macro diagnosis.

[pansywags]

Hi, just wanted to see how you and Lennox are doing. Thinking of you both.

[Squirt's Mom]

Me, too... I was wondering how things are going with you?