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Chiari-like malformation is found to be progressive

RodRussell

Well-known member
UK researchers, including Drs. Rusbridge, Driver, and McGonnell, reported to the ACVIM in a June 2011 study that CM-affected cavaliers' foramen magnums and the length of cerebellar herniation "increased significantly" between MRI scans averaging 9.5 months apart. they concluded:

"This work could suggest that overcrowding of the caudal cranial fossa in conjunction with the movements of cerebrospinal fluid and cerebellar tissue secondary to pulse pressures created during the cardiac cycle causes pressures on the occipital bone. This leads to a resorption of the bone and therefore an increase in caudal cranial fossa and foramen magnum size allowing cerebellar herniation length to increase."

See http://bit.ly/qUJK1F for more details.
 
I thought I was going to have a day off but can you please explain in laymans terms? What about mild cm that never develops a syrinx but is symptomatic? Does this have some help with the friend we have?

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If I'm reading it right that cm doesn't determine presence of sm and other factors? That's something I've wondered about. Do we know if they were symptomatic? I'm asking because so many people feel severity of SM but knowing symptomatic CM cavaliers like Dougal for example

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I thought I was going to have a day off but can you please explain in laymans terms? What about mild cm that never develops a syrinx but is symptomatic? Does this have some help with the friend we have?

I think it means that CM can get worse. The foramen magnum -- that hole in the back of the occipital bone of the skull -- actually can get bigger, and as it does, more of the cerebellum can squeeze through.

The researchers' hypothesis is that the over-sized cerebellum, combined with the movements of cerebrospinal fluid and cerebellum during heart beats, cause pressure on the occipital bone. This leads to the bone reducing in size, thereby enlarging the foramen magnum, allowing more of the cerebellum to squeeze through.

That is all I know.
 
UK researchers, including Drs. Rusbridge, Driver, and McGonnell, reported to the ACVIM in a June 2011 study that CM-affected cavaliers' foramen magnums and the length of cerebellar herniation "increased significantly" between MRI scans averaging 9.5 months apart. they concluded:

"This work could suggest that overcrowding of the caudal cranial fossa in conjunction with the movements of cerebrospinal fluid and cerebellar tissue secondary to pulse pressures created during the cardiac cycle causes pressures on the occipital bone. This leads to a resorption of the bone and therefore an increase in caudal cranial fossa and foramen magnum size allowing cerebellar herniation length to increase."

See http://bit.ly/qUJK1F for more details.

At the health day last November Dr McGonnell reported that all the cavalier whelps she studied in the Foetal Tissue Research had a suture in the middle of the Supraoccipital bone ( apparently it is unusual to find this within bone ) which appeared to close before birth ( early fusion )

The whelps had less high quality ( weak ) bone, lots of marrow and increased blood cells and they all had disorganised structure and large blood vessels.

http://www.cavaliertalk.com/forums/...lub-Health-Day.-Part-4-Foetal-Tissue-Research

I wonder if this weak bone in the cavalier skull contributes to the reported resorption.

At post-mortem Monty ( Ch. Mareve Indiana ) was found to have a large keyhole shaped foramen magnum.
The hole was partly covered by cartilage and that was possibly the reason his symptoms did not manifest until he was an old man. The cartilage was more flexible and crushed his brain less than the bone that would normally be there.
 
I see this announcement brought the usual reaction from breeders who demand they should be given up-to-date information, but then attacks anything that suggests there really are deep seated health problems in Cavaliers.

An abstract written by leading researchers, including the formerly highly praised head of the Foetal Tissue Research, gives proven facts about 12 cavaliers and suggests what may be happening.

Below is an illustration on how it was received.

In a couple of weeks time the highlighted words and phrases will be parroted by people that have not even read the report..................

Some people are very good at making the bullets for others to fire..........................

"A study conducted on 12 dogs ............ I have faith in the researchers, but find it difficult to accept on those figures that one could make any hard and fast statement, surely?"

"I just find it really difficult to swallow these sweeping statements based on such a small percentage of dogs"


"What I have a problem with it how can you reasonably expect anyone to take as "gospel" something based on 12 dogs.

Hard and fast statement? sweeping statements? gospel?

No, I don't think so. Just a report on a piece of research and a suggestion as to what it may mean.
 
Now wait a minute. I don't want to get in the middle of what people say but this topic does hit home. I'm not saying anything about this research because I know it is something we all want. I want to speak for 2 cavaliers and one specifically that is a pet owner just wanting answers. If you haven't read my blog, its funny because I just wrote about this before this came out. It has nothing to do with research. I can't speak for them because I don't know and I don't want to debate on a forum they are not on. You can read my blog www.fightforella.blogspot.com.

They have symptomatic CM cavaliers and bravely spoke out about it. I commend them for it and especially when they are scanning multiple times and helping with research. After the one with symptomatic CM she spent over a year researching getting a new cavalier from 2 fully scanned SM clear parents and even scanned grandparents.

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... They have symptomatic CM cavaliers and bravely spoke out about it. I commend them for it and especially when they are scanning multiple times and helping with research. After the one with symptomatic CM she spent over a year researching getting a new cavalier from 2 fully scanned CM/SM clear parents and even scanned grandparents.

I think symptomatic CM cavaliers (which means, the dog does not have SM, and therefore is an "A", but does suffer pain from CM) may be a loophole in the SM breeding protocol. The protocol okays breeding any cavalier which does not have SM. They are the "A" grade cavaliers. I long have suspected that the pain of CM/SM really is the pain of CM alone. I don't recall that any studies have refuted this hunch.

There are CM/SM cavaliers without symptoms, which includes no displays of pain. So it is possible to have SM and not, at least, give outward evidence of pain. And there are non-SM cavaliers, having only CM, which display signs of severe pain. So, why not reason that the pain experienced by CM/SM dogs is due to the CM and not the SM?

Should the SM breeding protocol be revised to ban symptomatic "A" cavaliers? I don't know, because it may be that breeding any "A" is better than breeding no "A" at all. This is a question for the geneticists and the neurologists to answer.
 
I see this announcement brought the usual reaction from breeders who demand they should be given up-to-date information, but then attacks anything that suggests there really are deep seated health problems in Cavaliers. ...

Yes, interesting, isn't it? Thank you for being so concise in your analysis. I could not put my finger on the irony, like you have.
 
I think symptomatic CM cavaliers (which means, the dog does not have SM, and therefore is an "A", but does suffer pain from CM) may be a loophole in the SM breeding protocol. The protocol okays breeding any cavalier which does not have SM. They are the "A" grade cavaliers. I long have suspected that the pain of CM/SM really is the pain of CM alone. I don't recall that any studies have refuted this hunch.

There are CM/SM cavaliers without symptoms, which includes no displays of pain. So it is possible to have SM and not, at least, give outward evidence of pain. And there are non-SM cavaliers, having only CM, which display signs of severe pain. So, why not reason that the pain experienced by CM/SM dogs is due to the CM and not the SM?

Should the SM breeding protocol be revised to ban symptomatic "A" cavaliers? I don't know, because it may be that breeding any "A" is better than breeding no "A" at all. This is a question for the geneticists and the neurologists to answer.

Well my friend said I need to cm/sm will be here next week and I need to play with elton. I know one is a breeder but even with a very good "A" would never breed a symptomatic cavalier. I would think no one should breed any dog that is symptomatic of anything. Off to talk to my 10 lb rescue for a week, elton.

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Rod,

I just edited my post but you quoted it. I stand corrected, the parents were SM clear but both grandparents were scanned. Bottom line, she did her research as will I if I ever get a puppy.

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This is very interesting given my Jack has moderate symptoms and CM with a subjective "pre-syrinx". It is so strange how some dogs with a large clearly visible syrinx are asymptomatic or have less symptoms than Jack who has mild to moderate CM with ?pre-syrinx. I wonder if I get Jack re-scanned if it will show an increase in his CM or possible true syrinx formation. Gosh I hate this disease!
 
Just my 2 cents, sometimes I think its the cm and not sm too.

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I second that! Just from personal experience. I'm sure many of you saw the terrible videos of Flash as a puppy. He did not have SM but had moderate/sever CM. Although I fully expect he will have SM by the time we rescan him I saw just how painful the CM was for him.
 
I second that! Just from personal experience. I'm sure many of you saw the terrible videos of Flash as a puppy. He did not have SM but had moderate/sever CM. Although I fully expect he will have SM by the time we rescan him I saw just how painful the CM was for him.


CHIARI-LIKE MALFORMATION IS FOUND TO BE PROGRESSIVE


Is it not the Genes that are causing the CM/SM Problems for our Cavaliers.

As has been said by the Researchers that there are Several/Many Genes involved in this Complex Problem for the Cavalier Breed.

As the Recent Veterinary Paper just Published has Reported ,Selective Cavalier Breeding for SM stated that the High Prevelance of SM suggests that Eliminating the Genetic Risk Factors may be difficult because the Prevelance of the Determinant Genes, those Genes which are causing CM/SM within the Cavalier Population is therefore likely to be High.

If the CM/SM Cavalier Problem is going to be difficult to over -come with Selective Breeding, this is very serious Information for the Cavalier Breed to have been given, in-fact for our Cavaliers ,I think it's the worst news possible they could get.

Bet
 
including the formerly highly praised head of the Foetal Tissue Research

I have always said to so many people, breeders and pet owners alike, that this researcher who had become flavour of the month with breeders as long as her research seemed safe and results distant and no real intractable problem was yet implied with the breed even at foetal stage, would suddenly be (like all the others) criticised and her results disputed as soon as she had actual results that showed otherwise.

So sad, so typical, but no surprise at all as it fits the pattern. Expect a cutoff now in support for her work and in donations, going on other experience.

So far even 800 dogs has been 'too small a sample' for research results for some. :rolleyes:

And if more whelp donations were made, there would be more information to work from.

I feel sorry for the breeders who have really championed this needed research and wonder if they have had a bit of an eye opening to the frustration felt by so many -- breeders and breed lovers -- at the general reception of research results by breed clubs. Though it does provide yet more evidence for the KC that there is a serious problem in the club breeder community, not just the dogs.

Surely all these *consistent* results that suggest *major*, widespread and deep-seated health problems in the breed cannot all be fluke results? :sl*p:
 
Just my 2 cents, sometimes I think its the cm and not sm too.

Not sure what you are saying, but the two are very clearly seen to be connected. However in dogs CM alone only rarely seems to cause problems and there's little evidence that CM is the source of the pain and not the SM that develops from it. It is known that some dogs like some humans have very different CSF movement and this almost surely accounts for why some dogs have more difficulty with CM alone. There are likely a lot of internal factors on how that fluid is moving and why it is more aggravating to one dog than the vast majority of dogs with SM.

I have only come across a tiny handful of dogs with CM causing significant symptoms and that is what the neurologists say as well. It rarely shows up as the sole factor on MRI. In such cases it is just as serious as SM and should not be discounted -- as it too often is -- as 'only' CM (as in 'thank God my dog 'only' has CM' -- if there are symptoms, it makes little difference to the dog).

As for why some dogs with lots of syrinxes have few to no symptoms -- this isn't a very common situation according to neurologists, so it isn;t 'the CM and not the SM', but it does happen. The reason why is likely to be the same as the above -- dogs vary in how the CSF moves; the size and shape of the syrinx will have an affect (eg a very long narrow set of syrinxes filling the spine is not 'worse' than a very short single wide and lopsided syrinx in terms of pain research, though it may look as if the MRI is 'worse'. It actually probably is not). And as Dr Marino has said many times in presentations -- syrinxes typically come on slowly, and dogs can adjust to the very slow progression to survive with the pain over time (a terrible situation though the body does sometimes adapt -- it isn't an excuse for not thinking there aren't serious issues in cavaliers having syrinxes in the first place no matter the symptoms or lack of same...). He has said he has seen MRIs in cavaliers where the dog has adapted to manage the pain, that if he'd seen in a dog that had just come in with trauma-induced SM -- eg as a result of a head impact or other accident -- the dog would almost definitely need to be euthenised as the pain would be unbearable.

Anyone who lives with any kind of pain syndrome will know that you do generally adjust over time to increased increments of pain. If the pain is mostly in the head, as is probably the case with canine SM (it is in humans), it may be very hard to ever see 'pain' that owners would recognise -- it may be that lots of those supposedly 'asymptomatic' dogs are not asymptomatic at all but suffer a good deal. There is a research programme that has just started to try and find ways to assess pain in SM dogs as the existing techniques only can pick up very obvious physical signs and few of the 'internal' signs that are most often reported by humans.

Rod, I don't think there is any implied gap in the breeding recommendations -- the neurologists who drew it up (and I was at the meeting where they approved it) definitely never thought any breeder would be so stupid or cruel as to breed a dog that is symptomatic for anything. You are right that perhaps on some reported evidence, the advice needs to now clearly state that A dogs show no symptoms, as is noted for lower grade dogs (D etc).
 
I had several conversations with breeders who were worried that their dogs were exhibiting some symptoms, but when they were subsequently scanned they were graded "A".

These breeders seemed to expect the scanning centre to confirm or deny their dog had symptoms. All the scanning centres can do is MRI scan and interpret the scan results.

Gives a "carte blanche" to breeders to disregard possible symptoms.

Unfortunately, the presence of symptoms of discomfort or pain is entirely down to breeder perception, understanding and HONESTY.

How many people see that which they do not want to see ?

Maggie
 
I had several conversations with breeders who were worried that their dogs were exhibiting some symptoms, but when they were subsequently scanned they were graded "A".

These breeders seemed to expect the scanning centre to confirm or deny their dog had symptoms. All the scanning centres can do is MRI scan and interpret the scan results.

Gives a "carte blanche" to breeders to disregard possible symptoms.

Unfortunately, the presence of symptoms of discomfort or pain is entirely down to breeder perception, understanding and HONESTY.

How many people see that which they do not want to see ?

Maggie


According to one breeder who has read the above none of her wide circle of friends would breed from a cavalier that was anything other but normal in every way, however nice they were.

I understood her circle of breeder friends include those that used the BIS dog that was diagnosed with SM at the age of 14 months?
A dog widely known to be affected because the owner had shown the scan & certificate round championship shows.
A dog that scanned so badly that the neurologist said he should never be bred from, would not be described by most people as normal in every way.
 
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