RodRussell
Well-known member
Maybe Cavaliers Don't Even Have Chiari-like Malformation (CM)! Read about it here:
http://www.cavalierhealth.org/editorial.htm
http://www.cavalierhealth.org/editorial.htm
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Maybe Cavaliers Don't Even Have Chiari-like Malformation (CM)!
- Thread starter RodRussell
- Start date
RodRussell
Well-known member
Maybe cavaliers don't even have chiari-like malformation(cm)!
MAYBE CAVALIERS DON'T EVEN HAVE CHIARI -LIKE MALFORMATION(CM)!
So, are the Smaller Heads that many Cavaliers have to-day , could be involved in these findings.
The Smaller Cavalier Heads started to appear in the early 1980's .the first Recorded SM Case of SM in a Cavalier was I believe 1986.
It has been reported that the Cavaliers' Heads don't grow in conjunction with their Brains .
I know that the excuse will be being given by some Cavalier Breeders that SM is in other Breeds , but it is said by Researchers that SM is more Prevalent in Cavaliers and is there any other other Breed whose Head Shape has been Bred Smaller in the last 30 years like the Cavaliers' Heads have.
In the Foetal Research ,85 Cavalier Whelps all had the Malformed Bone, so is this Bone normal for our Cavalier Breed and their SM Problem is more to do with the Minuterizing of their Heads.
Food For Thought.
Bet
MAYBE CAVALIERS DON'T EVEN HAVE CHIARI -LIKE MALFORMATION(CM)!
So, are the Smaller Heads that many Cavaliers have to-day , could be involved in these findings.
The Smaller Cavalier Heads started to appear in the early 1980's .the first Recorded SM Case of SM in a Cavalier was I believe 1986.
It has been reported that the Cavaliers' Heads don't grow in conjunction with their Brains .
I know that the excuse will be being given by some Cavalier Breeders that SM is in other Breeds , but it is said by Researchers that SM is more Prevalent in Cavaliers and is there any other other Breed whose Head Shape has been Bred Smaller in the last 30 years like the Cavaliers' Heads have.
In the Foetal Research ,85 Cavalier Whelps all had the Malformed Bone, so is this Bone normal for our Cavalier Breed and their SM Problem is more to do with the Minuterizing of their Heads.
Food For Thought.
Bet
RodRussell
Well-known member
Maybe cavaliers don't even have chiari -like malformation ( cm) !
MAYBE CAVALIERS DON'T EVEN HAVE CHIARI -LIKE MALFORMATION(CM)!
In Dr Rusbridge's Thesis ,she mentioned the Minaturization of Cavaliers , what was Minatureized in our Cavalier Breed.
Was it their Bodies , Heads or what ,perhaps some -one will tell me?
Bet
MAYBE CAVALIERS DON'T EVEN HAVE CHIARI -LIKE MALFORMATION(CM)!
In Dr Rusbridge's Thesis ,she mentioned the Minaturization of Cavaliers , what was Minatureized in our Cavalier Breed.
Was it their Bodies , Heads or what ,perhaps some -one will tell me?
Bet
RodRussell
Well-known member
I think she was referring to minaturization prior to the creation of the breed -- the minaturization which created toy dogs. At any rate, that point has not been repeated in the past few years, during which much more has been learned from additional research. I am unaware of any research showing that cavalier head sizes have reduced over the years since 1927.
The 2009 and 2010 reports referred to in the cited editorial conclude that the skull size appears to not be a factor leading to SM, but instead that the cerebellum is oversized for the skull. So, apparently the problem is the size of the brain and not the size of the head.
sunshinekisses
Well-known member
the brain is too big?? How the *cuss* does that happen. I also thought I had read that the cavalier skull finishes growing too soon...that the bones fuse too early. Really all of this is very confusing especially to a newbie that has future plans for breeding. What I wish would happen is more cavaliers get scanned and have dna samples for research.
I really don't think anyone can say the skulls are smaller today than years ago, because no one has done any measurements. I would like to see numbers before that statement can be made because I don't really see any head differences in older pictures I have seen. I have actually noticed a few dogs in the ring with quite large heads. I have also seen a few pin-heads but I don't think size of head would be a reason to say this dog will be more likely for SM or not. Not enough research has been done...not enough dogs have been scanned. JMO.
I really don't think anyone can say the skulls are smaller today than years ago, because no one has done any measurements. I would like to see numbers before that statement can be made because I don't really see any head differences in older pictures I have seen. I have actually noticed a few dogs in the ring with quite large heads. I have also seen a few pin-heads but I don't think size of head would be a reason to say this dog will be more likely for SM or not. Not enough research has been done...not enough dogs have been scanned. JMO.
Maybe cavaliers don't even have a chiari -like malformation (cm) !
MAYBE CAVALIERS DON't EVEN HAVE A CHIARI -LIKE MALFORMATION (CM) !
All Dogs have descended from Wolves ,so why do not all Breeds of Dogs have SM,also it has been stated often enough ,that the Cavaliers' Brain is like getting a size 10 foot into a Size 6 Shoe.
However the Cavalier Breed is nearly at the Point of Extinction ,because of SM and MVD, so where SM has come from is least of our beloved Cavaliers' worries ,it is in the Cavalier Breed, yet some Vociferous ,Vitirolic Cavalier Breeders are still doing all they can to put a stop to the KC/BVA MRI Scanning Scheme from going ahead.
Is it because they are scared they won't be able to sell their Cavalier Puppies and their Incomes will be damaged, or will it be disclosed whose Cavaliers have been involved with SM and this will be known to all in the Cavalier World?
I just cannot understand why some Cavalier Breeders are trying to Thwart this Scheme, I know I would be so Ashamed to be doing this after hearing the Cavalier Screaming in Pain on the PDE TV Program ,it's a Sound I will never forget.
Also to know that those Cavalier Breeders could be contributing to Cavaliers to a Life-Time of Medication for SM to keep their SM Pain under control,when according to the SM Researchers this MRI Scheme could go to-wards helping the Suffering of the Cavalier Breed from SM.
I guess , it takes all kinds of Folk in the Cavalier World , those who Truly Love the Breed , and the Small Minority who only pay Lip Service to the Cavaliers' Health Problems.
Bet
MAYBE CAVALIERS DON't EVEN HAVE A CHIARI -LIKE MALFORMATION (CM) !
All Dogs have descended from Wolves ,so why do not all Breeds of Dogs have SM,also it has been stated often enough ,that the Cavaliers' Brain is like getting a size 10 foot into a Size 6 Shoe.
However the Cavalier Breed is nearly at the Point of Extinction ,because of SM and MVD, so where SM has come from is least of our beloved Cavaliers' worries ,it is in the Cavalier Breed, yet some Vociferous ,Vitirolic Cavalier Breeders are still doing all they can to put a stop to the KC/BVA MRI Scanning Scheme from going ahead.
Is it because they are scared they won't be able to sell their Cavalier Puppies and their Incomes will be damaged, or will it be disclosed whose Cavaliers have been involved with SM and this will be known to all in the Cavalier World?
I just cannot understand why some Cavalier Breeders are trying to Thwart this Scheme, I know I would be so Ashamed to be doing this after hearing the Cavalier Screaming in Pain on the PDE TV Program ,it's a Sound I will never forget.
Also to know that those Cavalier Breeders could be contributing to Cavaliers to a Life-Time of Medication for SM to keep their SM Pain under control,when according to the SM Researchers this MRI Scheme could go to-wards helping the Suffering of the Cavalier Breed from SM.
I guess , it takes all kinds of Folk in the Cavalier World , those who Truly Love the Breed , and the Small Minority who only pay Lip Service to the Cavaliers' Health Problems.
Bet
anniemac
Well-known member
Having a cavalier with sm, I am not saying this in anyway to be interpretted to have anything to do with the scheme. I think they should have mri, wait until 2 1/2.
I want to say that cavaliers are not the only breed with SM. Actually several toy breeds have been found to have SM. There has just been more research on cavaliers. It might be more, common but to say it is only this breed is not correct. I don't know the comparision with other toys. Now, we may be lucky to have more research and start a breeding scheme.
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I want to say that cavaliers are not the only breed with SM. Actually several toy breeds have been found to have SM. There has just been more research on cavaliers. It might be more, common but to say it is only this breed is not correct. I don't know the comparision with other toys. Now, we may be lucky to have more research and start a breeding scheme.
Sent from my Droid using Tapatalk
Davecav
Well-known member
Bet
You say
However the Cavalier Breed is nearly at the Point of Extinction ,because of SM and MVD.
I do think this is rather melodramatic. There are many healthy cavaliers leading normal lives. The breed is hardly at the point of extinction by any definition.
Like everyone else I hope that the mode of inheritabce can be pinpointed sooner rather than later.
But there are breeders (that Margaret Carter has said) who are trying their best to do everything possible, under the tough circumstances, to breed away from this condition and the early heart problems.
Extinction means that there are none of a particular species left.
With all the puppy farm bred cavaliers and BYB cavaliers being churned out (whether any of us like it or not) the breed will be going for many years to come.
Whether or not these establishments breed healthy cavaliers is a totally different argument.
You say
However the Cavalier Breed is nearly at the Point of Extinction ,because of SM and MVD.
I do think this is rather melodramatic. There are many healthy cavaliers leading normal lives. The breed is hardly at the point of extinction by any definition.
Like everyone else I hope that the mode of inheritabce can be pinpointed sooner rather than later.
But there are breeders (that Margaret Carter has said) who are trying their best to do everything possible, under the tough circumstances, to breed away from this condition and the early heart problems.
Extinction means that there are none of a particular species left.
With all the puppy farm bred cavaliers and BYB cavaliers being churned out (whether any of us like it or not) the breed will be going for many years to come.
Whether or not these establishments breed healthy cavaliers is a totally different argument.
anniemac
Well-known member
This was started by rod, so I know he did not write this with any means to hurt the health of the breed or kc/ebv scheme. If I'm wrong then he can correct me. I think there is a continued need for more research and that has nothing to do with the scheme.
Also, I don't want any cavalier to suffer no matter who they are. So if they need to be treated with medication, then so be it as long as it helps them from pain.
Sent from my Droid using Tapatalk
Also, I don't want any cavalier to suffer no matter who they are. So if they need to be treated with medication, then so be it as long as it helps them from pain.
Sent from my Droid using Tapatalk
Rod withall due respect I think you have misread the research -- which all pretty much agrees that there is a mismatch between 1) the skull being too small due to a formation similar but not the same as the Chiari Malformation in humans and 2) the brain having a larger volume that would be the norm for a breed of the cavalier's size. So the bone stops growing at a point when the brain keeps growing. My understanding from human specialists is that this too is what seems to happen with Chiari. Have any of these researchers actually agreed that they would not call this problem CM?
I think it would be unfortunate if breeders now misunderstand this all to mean there's no CM and that SM is the issue. There is clear evidence from the genome work that there are separate genes for CM and SM -- a key initial finding -- and that while not all CM dogs go on to get SM, all dogs with SM have CM. In about a fourth of cases dogs show symptoms from CM alone (this is much much higher in humans where Chiari is more common and causes the most pain). Some very eminent human SM specialists who attended both the SM events in the UK both agreed with a description of CM in dogs that is like, but not the same as, Chiari maformation.
Understanding the relationship between the genes for CM and those for SM and why some dogs switch on the SM genes and some do not is considered a quite critical part of current research.
From some breeder posts in reply to your posting elsewhere, I can see some already totally misunderstand what the genome research is about and ow will run with this interpretation as defense of ... well whatever misreadings they already have of existing research.:sl*p:
The issue of name for the condition was already debated at length and CM was chosen precisely because it was NOT meant to mislead people into confusing Chiari with a Chiari-like malformation. But a lot of neurologists continue to call CM 'Chiari malformation' in dogs (including some who were amongst the group at the meeting, that decided the condition should not be called Chiari malformation or COMS......go figure). But no matter how confusing, I think both those approaches still demonstrate that *all* these researchers and the ones cited in other papers define the issue as one of a malformed bone at the base of the skull which does not grow in accordance with brain development and therefore, due to a mismatch between resulting skull volume (caused by CM) and brain size, ends up compressing the hindbrain in a way similar to Chiari malformation in humans.
For what it is worth I know of geneticists and other specialists including some who have not said this publicly who believe the situation for the breed is quite dire and that it probably will not survive many more (human) generations before it faces too high a risk of seriously compromised and painful life if drastic action isn't taken. Given club breeder opposition to nearly every single thing done by researchers and the BVA to try to improve health, including the screening schemes they themselves demanded (but don;t want to follow once put in place) I cannot imagine the breed can continue much longer without outside international regulation on breeding.
Even people like Dr Jeff Samson, the Kennel Club's own genetics specialist, are now saying they think the breed is under threat and what he has stated at a couple of breed events is quite different from what he said in Pedigree Dogs Exposed. He now accepts probably 70% eventually have SM -- that is a shocking, shocking percentage with a serious neurological disorder considered one of the most painful and horrific health issues that humans can get. In a human population, that would bring national enquiries and massive funding to find out what is going wrong.
I think it would be unfortunate if breeders now misunderstand this all to mean there's no CM and that SM is the issue. There is clear evidence from the genome work that there are separate genes for CM and SM -- a key initial finding -- and that while not all CM dogs go on to get SM, all dogs with SM have CM. In about a fourth of cases dogs show symptoms from CM alone (this is much much higher in humans where Chiari is more common and causes the most pain). Some very eminent human SM specialists who attended both the SM events in the UK both agreed with a description of CM in dogs that is like, but not the same as, Chiari maformation.
Understanding the relationship between the genes for CM and those for SM and why some dogs switch on the SM genes and some do not is considered a quite critical part of current research.
From some breeder posts in reply to your posting elsewhere, I can see some already totally misunderstand what the genome research is about and ow will run with this interpretation as defense of ... well whatever misreadings they already have of existing research.:sl*p:
The issue of name for the condition was already debated at length and CM was chosen precisely because it was NOT meant to mislead people into confusing Chiari with a Chiari-like malformation. But a lot of neurologists continue to call CM 'Chiari malformation' in dogs (including some who were amongst the group at the meeting, that decided the condition should not be called Chiari malformation or COMS...
...go figure). But no matter how confusing, I think both those approaches still demonstrate that *all* these researchers and the ones cited in other papers define the issue as one of a malformed bone at the base of the skull which does not grow in accordance with brain development and therefore, due to a mismatch between resulting skull volume (caused by CM) and brain size, ends up compressing the hindbrain in a way similar to Chiari malformation in humans.For what it is worth I know of geneticists and other specialists including some who have not said this publicly who believe the situation for the breed is quite dire and that it probably will not survive many more (human) generations before it faces too high a risk of seriously compromised and painful life if drastic action isn't taken. Given club breeder opposition to nearly every single thing done by researchers and the BVA to try to improve health, including the screening schemes they themselves demanded (but don;t want to follow once put in place) I cannot imagine the breed can continue much longer without outside international regulation on breeding.
Even people like Dr Jeff Samson, the Kennel Club's own genetics specialist, are now saying they think the breed is under threat and what he has stated at a couple of breed events is quite different from what he said in Pedigree Dogs Exposed. He now accepts probably 70% eventually have SM -- that is a shocking, shocking percentage with a serious neurological disorder considered one of the most painful and horrific health issues that humans can get. In a human population, that would bring national enquiries and massive funding to find out what is going wrong.
RodRussell
Well-known member
I don't think that the bone at the base of the skull is malformed at all, as I interpret the 2009 and 2010 articles.
In the 2009 German study, Evaluation of the volumes of cranial cavities in Cavalier King Charles Spaniels with Chiari-like malformation and other brachycephalic dogs as measured via computed tomography. Schmidt MJ, Biel M, Klumpp S, Schneider M, Kramer M. Am J Vet Res. 2009 Apr;70(4):508-12; they wrote: "Results of this study suggested that descent of the cerebellum into the foramen magnum and the presence of syringohydromyelia in CKCSs are not necessarily associated with a volume reduction in the CF of the skull."
In the 2009 UK study, Comparison of cerebral cranium volumes between cavalier King Charles spaniels with Chiari-like malformation, small breed dogs and Labradors. H. R. Cross, R. Cappello, and C. Rusbridge. J Small Anim. Pract. 2009 Aug ; 50:399-405; they wrote: "Other small breeds of dogs had a proportionately smaller volume of parenchyma in their caudal fossa which can explain why, despite having a similar sized caudal fossa to CKCS, they do not experience overcrowding."
In the 2010 UK study, Volumetric Analysis Of Brain Parenchyma Within The Caudal Fossae Of Cavalier King Charles Spaniels. C Driver, C Rusbridge, H Cross, HA Volk. 22nd ECVN Annual Symposium, Sept. 2009; J Vet Intern Med, Jan/Feb 2010;24(1):242; they wrote: "This work supports recent evidence that caudal fossa size is not associated with SM, but that overcrowding of the caudal fossa leads to SM and may be caused by mesoderm insufficiency."
Granted, these may be cherry-picked passages, but they are consistent findings that there is no volume reduction in the caudal fossa. The definition of CM includes this element: "decreased caudal fossa volume".
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RodRussell
Well-known member
I am not aware that anyone fairly knowledgeable about SM has ever claimed that it has been found only in cavaliers. Dogs in a few other breeds have been diagnosed with SM, including the Bichon Frisé, Boston terrier, Brussels Griffon (Griffon Bruxellois), bull terrier, Chihuahua, French bulldog, Havanese, King Charles spaniel (the English toy spaniel), Maltese terrier, miniature dachshund, miniature and toy poodles, Papillon, Pomeranian, Pug, Shih Tzu, Staffordshire bull terrier, and the Yorkshire terrier.
RodRussell
Well-known member
At the Syringomyelia International Conference at the Royal Veterinary College held in November 2006, the participants agreed to define Chiari-like malformation as "decreased caudal fossa volume with caudal descent of the cerebellum, and often the brainstem, into or though the foramen magnum." I now have been told that the definition of Chiari-like malformation (CM) has been revised, and that it no longer is limited to just a "decreased caudal fossa volume".
Now, the definition of CM includes a mis-match due to the skull being too small and the brain being too large, meaning the ratio of the caudal fossa volume to the volume of the hindbrain parenchyma within the caudal fossa.
Here is how CM now is defined on Dr. Rusbridge's website:
"Chiari-like malformation (CM) is the most common cause of foramen magnum obstruction and syringomyelia in the dog. CM is a condition characterised by mismatch in size between the brain (too big) and the skull (too small). There is not enough room for the brain and the back part (cerebellum and medulla) is pushed out the FM."
And this is how Dr. Rusbridge describes what causes CM:
"CM is not yet fully understood. Somehow the miniaturisation process in the Cavalier went awry and unlike many other toy breeds the brain did not decrease in size in proportion with the skull. The Cavalier appears to have a brain more appropriate for a bigger dog."
This is a relief, because the old definition, focusing solely as it did upon the cavalier's caudal fossa volume, when compared to the caudal fossa volumes of other breeds, was reportedly proportionately consistent, according to how I have interpreted the 2009 and 2010 German and UK articles on the subject.
It may be that comparisons between the caudal fossa volume of cavaliers with the caudal fossa volume of other breeds is misleading and irrelevant. In the other breeds, the volume of the caudal fossa is adequate to accommodate the volume of the brain parenchyma, while in the CKCS, it is not. The researchers pretty consistently have hypothesized that the development of syringomyelia may be related to a cumulative effect of a small caudal fossa and an enlarged brain parenchyma within it.
Whether or not the size of the caudal fossa plays a major role in the mis-match is of little consequence. The important thing is to recognize that the CKCS has proportionately more hindbrain volume than other small breed dogs, and that this may be due to an overgrowth of the cerebellum in the embryo, or to early growth plate closure, or both.
Now, the definition of CM includes a mis-match due to the skull being too small and the brain being too large, meaning the ratio of the caudal fossa volume to the volume of the hindbrain parenchyma within the caudal fossa.
Here is how CM now is defined on Dr. Rusbridge's website:
"Chiari-like malformation (CM) is the most common cause of foramen magnum obstruction and syringomyelia in the dog. CM is a condition characterised by mismatch in size between the brain (too big) and the skull (too small). There is not enough room for the brain and the back part (cerebellum and medulla) is pushed out the FM."
And this is how Dr. Rusbridge describes what causes CM:
"CM is not yet fully understood. Somehow the miniaturisation process in the Cavalier went awry and unlike many other toy breeds the brain did not decrease in size in proportion with the skull. The Cavalier appears to have a brain more appropriate for a bigger dog."
This is a relief, because the old definition, focusing solely as it did upon the cavalier's caudal fossa volume, when compared to the caudal fossa volumes of other breeds, was reportedly proportionately consistent, according to how I have interpreted the 2009 and 2010 German and UK articles on the subject.
It may be that comparisons between the caudal fossa volume of cavaliers with the caudal fossa volume of other breeds is misleading and irrelevant. In the other breeds, the volume of the caudal fossa is adequate to accommodate the volume of the brain parenchyma, while in the CKCS, it is not. The researchers pretty consistently have hypothesized that the development of syringomyelia may be related to a cumulative effect of a small caudal fossa and an enlarged brain parenchyma within it.
Whether or not the size of the caudal fossa plays a major role in the mis-match is of little consequence. The important thing is to recognize that the CKCS has proportionately more hindbrain volume than other small breed dogs, and that this may be due to an overgrowth of the cerebellum in the embryo, or to early growth plate closure, or both.
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Maybe cavaliers don't even have a chiari -like malformation (cm)!
MAYBE CAVALIERS DON'T EVEN HAVE A CHIARI -LIKE MALFORMATION (CM) !
Karlin,
Thank -you for your Post.
I'm away now to watch Andy M, the Scot's Pin Up Boy on TV , hopefully winning his First Grand Slam.
Bet
Rod withall due respect I think you have misread the research -- which all pretty much agrees that there is a mismatch between 1) the skull being too small due to a formation similar but not the same as the Chiari Malformation in humans and 2) the brain having a larger volume that would be the norm for a breed of the cavalier's size. So the bone stops growing at a point when the brain keeps growing. My understanding from human specialists is that this too is what seems to happen with Chiari. Have any of these researchers actually agreed that they would not call this problem CM?
I think it would be unfortunate if breeders now misunderstand this all to mean there's no CM and that SM is the issue. There is clear evidence from the genome work that there are separate genes for CM and SM -- a key initial finding -- and that while not all CM dogs go on to get SM, all dogs with SM have CM. In about a fourth of cases dogs show symptoms from CM alone (this is much much higher in humans where Chiari is more common and causes the most pain). Some very eminent human SM specialists who attended both the SM events in the UK both agreed with a description of CM in dogs that is like, but not the same as, Chiari maformation.
Understanding the relationship between the genes for CM and those for SM and why some dogs switch on the SM genes and some do not is considered a quite critical part of current research.
From some breeder posts in reply to your posting elsewhere, I can see some already totally misunderstand what the genome research is about and ow will run with this interpretation as defense of ... well whatever misreadings they already have of existing research.:sl*p:
The issue of name for the condition was already debated at length and CM was chosen precisely because it was NOT meant to mislead people into confusing Chiari with a Chiari-like malformation. But a lot of neurologists continue to call CM 'Chiari malformation' in dogs (including some who were amongst the group at the meeting, that decided the condition should not be called Chiari malformation or COMS...
For what it is worth I know of geneticists and other specialists including some who have not said this publicly who believe the situation for the breed is quite dire and that it probably will not survive many more (human) generations before it faces too high a risk of seriously compromised and painful life if drastic action isn't taken. Given club breeder opposition to nearly every single thing done by researchers and the BVA to try to improve health, including the screening schemes they themselves demanded (but don;t want to follow once put in place) I cannot imagine the breed can continue much longer without outside international regulation on breeding.
Even people like Dr Jeff Samson, the Kennel Club's own genetics specialist, are now saying they think the breed is under threat and what he has stated at a couple of breed events is quite different from what he said in Pedigree Dogs Exposed. He now accepts probably 70% eventually have SM -- that is a shocking, shocking percentage with a serious neurological disorder considered one of the most painful and horrific health issues that humans can get. In a human population, that would bring national enquiries and massive funding to find out what is going wrong.
MAYBE CAVALIERS DON'T EVEN HAVE A CHIARI -LIKE MALFORMATION (CM) !
Karlin,
Thank -you for your Post.
I'm away now to watch Andy M, the Scot's Pin Up Boy on TV , hopefully winning his First Grand Slam.
Bet