KC health screening
it is vital everyone wanting to breed from these lines must get there dogs MRI screened. contact your vet to find your local test center.
SM has now been seen in every toy breed and is more prevalent in some like CKCS, Chihuahua, Griffon. We only know this because the breeders have made the effort and investment to scan there dogs to see if it is an issue in the breed. To get a clear picture you need to have 50% or more breeding dogs scanned and only then can you say if there is a problem in the breed. Unfortunately Pomeranian breeders are not pushing for testing in the UK even though it can be done for as little as £250. The south of england pom club http://www.southofenglandpomeranianclub.co.uk/ held a seminar on the 17th November 2014 and i can only hope this will make people see that it is not isolated to a couple of lines as the pom club web site states. We have already seen it in at least 6 different lines in the UK and there are poms around the world who have this condition. Some are descendants of these affected UK lines but some totally unrelated.
Sadly the seminar was said to have been well attended but it has not encourage the breed clubs or breeders to start testing for SM/CM and again yet another health condition is swept under the carpet and the breeders with affected dogs are carrying on regardless of the fact the parents and or grandparents of their dog are proven as affected and producers of this terrible condition.
It is new news to the pomeranian world as of 2012 and it is normal for people to want to say it is not an issue in the breed but with so many other toy breeds highly affected it is ignorant to think this way and for the breed clubs to make the statement that it is only a minority of affected lines is irresponsible when it is already proven to be in the most used lines in the uk which are behind and come from all the same dogs anyway. Until many more poms are tested there is no way of knowing the extent of affected poms and lines.
I have stopped using UK lines because of affected dogs from the UK being high percentage.
So far 5 current breeding and show poms from my kennel have been MRI'd and all are clear with NO CM or SM.
Even though all my dogs are now imports they will still be scanned in time because just because they show no symptoms does not mean they are not affected.
It is my feeling from research and experience that many dogs who have SM but no CM will not show any or obvious symptoms. It is the CM ( Malformation of the back of the skull ) that is responsible for the typical symptoms and pain. This makes perfect sense as in CM the skull is deformed pushing into the back of the brain and pushing down on the spinal cord as it enters the brain. This is what causes the air scratching and head tilt, shaking of the head and pain. The SM is pockets of excess (CSF) fluid in the spinal cord and depending on their placement depends on symptoms you might or might not see. These pockets of fluid push on the nerves and can cause weakness in the limbs so falling, limping, unable to stand can all be signs you will see. If the swelling is not in the areas affecting the limbs then you will not see these symptoms which is why you can still have an affected dog but it appears to be healthy. So those who are sayings there dog shows no signs but it is from affected lines does not mean it is clear. This can only be determined by an MRI Scan.
ALL CM affected 1 or 2 should not be bred from full stop only a clear CM 0 grade is acceptable for breeding.
We have to work in the same way they CKCS breeders are but sadly even when they have 2 or 3 generations of clears they are still producing affected offspring. Without more testing the experts leading the studies cannot work out why this is happening and how to breed away from this and to find hopefully a DNA test.
What is Syringomyelia?
Syringomyelia is a condition whereby fluid filled cavities develop within the spinal cord. Some refer to SM as "neck scratcher's disease" because scratching in the air near the neck is a common sign.
What causes it?
Syringomyelia is a consequence of an obstruction to cerebrospinal fluid (CSF) flow. In the normal mammal, the CSF around the brain shunts back and forth with the arterial pulse. If this rapid efflux and influx is obstructed then the pressure wave is transmitted down the spinal cord distending it below the blockage. This results in the formation of a cavity or syrinx. Syringomyelia can occur from any blockage in the subarachnoid space (space containing CSF around the brain and spinal cord). However, the most common cause is the cerebellum within the foramen magnum (i.e. the back of the brain poking though the hole at the back of the skull). The cerebellum is pushed (herniated) out the skull because there is not enough space since the volume of the back of the skull (occipital bone) is too small. This condition occurs in many small breeds but is common in the cavalier King Charles spaniel (CKCS) (conservative estimates at least 50% of the breed although only a proportion are severe enough to have clinical signs). It is similar to the human condition Chiari malformation (some vets refer to it as Arnold Chiari syndrome which can be confusing as the original description by Arnold was of syringomyelia associated with spina bifida and this is not the case in the CKCS).
What are the clinical signs of syringomyelia?
By far the most important sign of syringomyelia is pain. This is most commonly localised to the neck region but may be difficult to define or intermittent. Owners often report that their dog is worse at night; when first getting up; during hot or cold temperature extremes; when excited; or related to posture e.g. preferring to sleep with their head elevated. They may seem to be overly sensitive to touch on one side of the neck / ear / shoulder / sternum. In addition some affected dogs scratch at one area of the shoulder, ear, neck or sternum. This is typically one side only, while the dog is moving and sometimes without making skin contact Some dogs, more commonly younger patients, develop a scoliosis (twisted spine). Some severe cases may have other neurological deficits such as fore and hindlimb limb weakness and ataxia (wobbliness). Facial nerve paralysis, deafness and seizures have also been associated with the condition but a link has yet to be proven.
What age of dog is affected?
Clinical signs of syringomyelia secondary to occipital hypoplasia are usually recognized between 6 months and 3 years of age. However, dogs of any age may be presented and dogs with more severe disease tend to be presented before two years of age.
Do the signs get worse?
Progression of the disease is very variable. Some dogs have the tendency to scratch with mild pain only and other neurological signs, such as paresis, never or very slowly develop. Others can be severely disabled by pain and neurological deficits within 6 months of the first signs developing. A small syringomyelia may also be found as an incidental finding, with no recognised clinical signs, in the investigation of another neurological disease.
Are there any diseases with similar signs to syringomyelia?
The main diseases to rule out are other causes of neck pain e.g. disc disease (uncommon in dogs less than two years of age); CNS inflammatory diseases and other malformations. If scratching or face rubbing is the main sign then skin disease should be eliminated.
How do I know if my dog has Syringomyelia?
The only way to confirm a diagnosis is by MRI (Magnetic Resonance imaging). This is essentially a picture of the water content of the body presented in a series of slices (like a loaf of bread). Nervous tissue, which contains a lot of water, is not imaged by x-rays but is shown in great detail by MRI. The syringomyelia can be easily visualised as a pocket of fluid within the spinal cord. In severe cases the syrinx is so wide that only a thin rim of spinal cord remains
If my dog has been diagnosed with Syringomyelia what are the options?
No one can make the decision for you about what is best for your dog.
Long-term studies of medical management of syringomyelia are not available yet. The drugs used to treat syringomyelia can be divided into 3 types:
drugs which reduce CSF production;
Pain in mild cases may be controlled by non steroidal anti-inflammatory drugs (NSAIDs) e.g. Rimadyl and Metacam. In more severe cases anticonvulsants, which have a neuromodulatory effect on hyperexcitable damaged nervous system, may be useful, for example gabapentin (Neurontin Pfizer;- these are not licenced for dogs). Oral opioids, e.g. pethidine or methadone are also an alternative.
Drugs which reduce CSF production
Proton pump inhibitors such as omeprazole (Losec or Prilosec) can inhibit cerebrospinal fluid formation and therefore may be valuable; clinical data on their use and effectiveness for SM is currently lacking. This drug is unlikely to be useful in the long term as therapy longer than 8 weeks duration is not recommended as this may increase the risk for stomach cancer. Carbonic anhydrase inhibitors such as acetazolamide (Diamox; Lederle laboratories) also decrease CSF flow and may also be helpful in treating syringomyelia although adverse effects of abdominal pain, lethargy and weakness may limit long term use.). Furosemide also decreases intracranial pressure and therefore could be useful in the treatment of syringomyelia.
Corticosteroids are very effective in reducing both pain and neurological deficits although the exact mechanism is not known. It has been suggested that these drugs reduce CSF pressure however laboratory evidence of this is lacking. They possibly have a direct effect on pain mediators such as substance P. Although corticosteroids may be effective in limiting the signs and progression, most dogs require continuous therapy and subsequently develop the concomitant side effects of immunosuppression, weight gain and skin changes. If there is no alternative then the lowest possible dose that can control signs is used. Alternate day therapy is preferred.
Surgical management is indicated for dogs with significant pain or with worsening neurological signs. The aim is to restore CSF dynamics and if this can be achieved then the syrinx can resolve. The most common procedure for Chiari like malformation is suboccipital decompression where the hypoplastic occipital bone and sometimes the cranial dorsal laminae of the atlas are removed (with or without a durotomy) to decompress the foramen magnum. The success reported in the small case series varies from no improvement to post operative resolution of the syrinx. Syringosubarachnoid shunting has also been described. In the author's experience surgery is usually successful at significantly reducing the pain but some dogs may still show signs of discomfort /scratching. Also in the author's experience signs may recur in a proportion of dogs after several months/years. One must weigh the risks and benefits of surgery versus medication versus no intervention. Remember, progressive disease means that no action may enable further deterioration.
When to have surgery?
There is more chance of success if the surgery is done early in the course of the disease before permanent damage has occurred. Surgical management is indicated for dogs with significant pain or with worsening neurological signs.
What are the risks of surgery?
There are major blood vessels in the area and if traumatised the dog could quickly bleed to death. Although not actually operating on the brain/spinal cord, it is in close proximity and there is a risk of permanent neurological injury. In reality complications from surgery seem to be rare.
Can the disease recur?
In the authors' experience signs may recur in a proportion of dogs after several months/years due to redevelopment of syringomyelia. The newly created "space" from surgery may fill in with scar tissue. If this happens, repeat surgery may be indicated; some owner prefer to continue with medical management e.g. with frusemide, NSAIDs, gabapentin or corticosteroids.
What post surgery drug treatment would you advise?
Dogs are hospitalised until comfortable enough for morphine-like-drugs to be discontinued and then discharged on a combination of non steroidal anti-inflammatory drugs (e.g. Rimadyl) and gabapentin (Neurontin). This is withdrawn when the dog is comfortable (about 2 weeks in most cases).
© Clare Rusbridge BVMS DipECVN MRCVS
- www.fckc.com (French website)
- Canine Syringomyelia
- Report from the Chiari-Like Malformation and Syringomyelia Working Group
- Syringomyelia in Cavalier King Charles Spaniels
- Chiari & Syringomyelia News
- History of the Syndrome
- Syringomyelia News April/May 2007
- Syringomyelia (SM) and the Cavalier King Charles Spaniel
- Canine Syringomyelia Support Email Group
- Syringomyelia - Genetic Challenges to Good Health