Syringomyelia (SM) and the Cavalier King Charles Spaniel

IN SHORT: | Symptoms | Diagnosis | Treatment | Breeders' Responsibilities

Rusbridge Winter 2007 SM Update NCSU 2006 Study Reports Reduced Rate MRI Clinics

Cornell June 2007 Report on frontal-sinus size and SM

IN DEPTH:

-- Chiari-like malformation

Breeders' Responsibilties

Dr. Rusbridge's Syringomyelia News Autumn 2007 Research Update

Dr. Rusbridge's Syringomyelia News 2007 Research Update

SM Breeding Protocol

Board Certified Veterinary Neurologists

MRI Screening Protocol

Questions for Cavalier Breeders

Primary Secretory Otitis Media (PSOM)

Canine Health Testing Clinics

A website devoted to syringomyelia in Cavaliers is Karlin Lillington's SM.CavalierTalk.com.

Two SM support email groups for owners of dogs with SM are Yahoo! Group: Arnold Chiari Dogs and Yahoo! Group: CKCS SM-support .

Two SM email discussion groups are Yahoo! Group: CKCS-SM and Karlin Lillington's CavalierTalk: SM and MVD Cavaliers Forum.

Clare Rusbridge video DVD "Syringomyelia Seminar", contact penny.knowler@ntlworld.com

A website and a book about a Cavalier diagnosed with syringomyelia is For the love of Ollie.

One Cavalier's daily blog about his life with SM: Charlie's SM Weblog

See additional Related Links below.

In Depth:

CavalierHealth.org Copyright © 2004 Blenheim Company Syringomyelia (SM -- also known as syrinx and hydromyelia, and occasionally mis-identified as Arnold Chiari malformation) is a condition of the development of fluid-filled cavities in the spinal cord, due to abnormal flow of cerebrospinal fluid (CSF) between the brain and the spinal cord through the foramen magnum at the base of the skull. It more technically is described as syringomyelia secondary to Chiari-like malformation (CM or CLM). CM also is referred to as occipital hypoplasia (OH) or caudal occipital malformation syndrome (COMS).

SM is rare in most breeds but has become very widespread in Cavalier King Charles spaniels. Some researchers estimate that as many as 95% of CKCSs have Chiari-like malformation (CM or CLM), the skull bone malformation believed to cause syringomyelia, and that up to 50% of Cavaliers have SM. It is worldwide in scope and not limited to any country, breeding line, or kennel, and experts report that it is believed to be inherited in the Cavalier King Charles spaniel. The severity and extent of syringomyelia also appear to get worse in each succeeding generation of Cavaliers. Other breeds known to be affected to a lesser extent include the Boston terrier, Brussels Griffon, bull terrier, Chihuahua, King Charles spaniel (the English toy spaniel), and the Yorkshire terrier.

Chiari-like malformation (CM or CLM) -- Occipital hypoplasia (OH) -- Caudal occipital malformation syndrome (COMS)

These three terms have been used to identify the malformation believed to cause syringomyelia. Although they technically mean different things, they often are used interchangeably. Some neurologists prefer one term over the others. However, researchers meeting at the International Conference on Syringomyelia at the Royal Veterinary College in London in November 2006 agreed upon the use of Chiari-like malformation (CM or CLM) to describe the malformation found in the Cavalier and to a lesser extent in a few other breeds.

4Chiari-like malformation (CM or CLM): The foramen magnum is a hole in the back of the skull, leading to the spinal cord. In the Cavalier breed, the back half of the skull is smaller than the typical toy dog breed. This condition is called Chiari-like malformation, named after a similar condition in humans, discovered by Dr. Hans Chiari. Chiari-like malformation is defined as "decreased caudal fossa volume with caudal descent of the cerebellum, and often the brainstem, into or though the foramen magnum." See Karen Kennedy's* Understanding Canine Chiari Malformation and Syrningomyelia for diagrams of the occipital bone and foramen magnum.

There is not yet a consensus among veterinary investigators as to how to measure the Cavalier's occipital bone to determine what should be the shape of the cerebellum within a "normal" CKCS's occipital bone. Dr. Clare Rusbridge, BVMS, MRCVS, PhD, DipECVN, of the Stone Lion Veterinary Centre in London, England, a leading investigator into SM, describes the three "classic features" of occipital malformation as: (1) loss of the normal round shape of the cerebellum, which can appear to be indented by the occipital bone; (2) displacement of the cerebellum into and through the foramen magnum, i.e. herniation; and (3) kinking of the medulla.

In a 2006 study conducted by Dr. Natasha J. Olby and Dr. Sofia Cerda-Gonzalez, both board certified veterinary neurologists, and others at North Carolina State University's College of Veterinary Medicine's Department of Clinical Sciences and the IAMS Pet Imaging Center in Raleigh, NC., they have concluded that the incidence of caudal fossa and cervical spinal abnormalities is high in Cavaliers, and that the pathogenesis of syringomyelia is multifactorial rather than due to a single malformation.

4Occipital hypoplasia (OH) has been used to describe the displacement of the cerebellum into the area of the foramen magnum and a kinking of the medulla and an indentation of the cerebellum. "Hypoplasia" is a medical term defined as underdevelopment or incomplete development, and so, "occipital hypoplasia" in this instance means an underdeveloped or incompletely developed occipital bone, which is part of the back of the skull. However, at the November 2006 London conference, this term was rejected because there is no proof yet that the condition is related to a hypoplastic occipital bone. The actual disorder is believed to be caused either by an unusually small occipital bone or a confining membrane within the occipital bone, resulting in the cavity in the skull containing the cerebellum to be too small to fully contain it, leading to overcrowding of the caudal fossa and obstruction of the neural structures, including the incomplete closure or development of the neural tube through which flows the cerebrospinal fluid (CSF).

Occipital hypoplasia is to be distinguished from occipital dysplasia, which is an incomplete ossification of the supraoccipital bone, causing a widening of the foramen magnum. The more brachycephalic is the shape of the dog's skull, the more likely there will be occipital dysplasia. The Cavalier is a brachycephalic breed, and therefore a combination of both occipital hypoplasia and occipital dysplasia can occur in the CKCS.

4Caudal occipital malformation syndrome (COMS), had been used, particularly by some specialists in the United States, to describe the disorder. However, at the November 2006 London conference, the term COMS also was rejected because there is no proof yet that the condition is related to a malformed occipital bone.

Because prior to the November 2006 London conference, CM and OH and COMS all were used to describe the same malformation, they all are used interchangeably in this article. See Karen Kennedy's* Understanding Canine Chiari Malformation and Syrningomyelia for scans of the occipital bone and foramen magnum, comparing "normal", mild Chiari" and "severe Chiari" dogs.

*Karen Kennedy, RTMR, MappSc, is a magnetic resonance imaging specialist with The London Health Sciences Centre, London, Ontario, Canada.

What SM is

Syringomyelia (SM) is defined as "a condition that results in the development of fluid-containing cavities within the parenchyma of the spinal cord. as a consequence of abnormal cerebrospinal fluid movement." (November 2006 International Conference on Syringomyelia).

Cerebrospinal fluid normally flows back and forth between the brain and spinal cord with each heart beat. As the heart pumps blood to the brain, the CSF flows from the brain through the hole called the foramen magnum to the spinal cord, to accommodate the increased volume of incoming blood.

Syringomyelia results when the cerebrospinal fluid is prevented from circulating normally between the brain and spinal cord, due to a narrowing or blockage of the CSF flow at the foramen magnum, thereby forcing the CSF at a higher than normal pressure into the spinal cord. The pressure difference causes the spinal cord to distend or pull apart, creating a cavity called a syrinx, and squeezing fluid from blood vessels into the cavity. Technically, hydromyelia is a dilatation of the central canal within the spinal cord, and syringomyelia is the cavitation of the spinal cord parenchyma. Combined, they are referred to either as syringohydromyelia (SHM) or hydrosyringomyelia. The disease is referred to generally as syringomyelia and SM herein. This condition is similar, but not identical, to Arnold Chiari Type I Syndrome in humans.

(Note: There are other forms of syringomyelia in canines: (a) spinal dysraphism or spinal dysplasia, a genetic disorder in which puppies normally under the age of three months display a bunny hopping gait and wide-based stance and scoliosis, due to the spinal cord not developing forming completely in the womb; and (b) SM caused by tumors, cysts, or trauma; and (c) possible SM-like neurological symptoms due to Chiari-like malformation in brachycephalic breeds. None are discussed here.)

Syringomyelia is an extremely serious, progressively worsening spinal disease which is rare in most breeds but is becoming very widespread in Cavalier King Charles Spaniels of all bloodlines. In May 2005, Dr. Rusbridge and Susan P. (Penny) Knowler, BSc (Hons), who have been studying the disease in several hundreds of Cavaliers, reported that a conservative estimate is that at least 50% of Cavalier King Charles Spaniels have a degree of Chiari-like malformation, although not all are so severely affected as to have syringomyelia.

Symptoms

The number of diagnosed cases in Cavaliers has increased dramatically since 2000. SM and CM very seldom can be detected in young puppies, as symptoms usually are not evident before the age of six months or even many years later. There is no way to know in advance of the symptoms whether a dog is normal or is a syringomyelia carrier which does not develop the disease but can pass it on to its offspring.

The condition causes damage to the spinal cord and usually results in symptoms of hypersensitivity, intense pain, and leg dysfunction. The primary symptoms may vary widely, and in some cases, a Cavalier may have SM without displaying any outward symptoms at all. It also is possible that a dog with Chiari-like malformation (CM) does not have syringomyelia (the syrinx in the spinal cord), but still may have symptoms of SM due to the CM obstructing the flow of cerebrospinal fluid (CSF).

Symptoms may vary widely among different dogs, but the earliest sign often is that the dog feels a sensitivity in its neck area, causing an uncontrollable urge to scratch at its neck and shoulders excessively, particularly when walking or during other forms of exercise. This is due to an increase in the pressure of the flow of cerebrospinal fluid through the central canal from the brain down the spinal column, causing the central canal to expand and press against the nerves of the spinal column and creating the needle-like tingling which prompts the dog to scratch.

As the disorder progresses, there usually follows increasingly severe pain around the dog's head, neck, and shoulders, causing it yelp or scream. It is believed to be a neuropathic pain, probably due to disordered neural processing in the damaged dorsal horn. As the disease destroys portions of the Cavalier's spinal cord, the dog may experience so much pain that it may contort its neck and may even sleep and eat only with its head held high. The dog may develop scoliosis, as a result. There may also be progressive weakness in the legs, so that walking becomes increasingly difficult. Some dogs deteriorate to the point of paralysis.

In a June 2007 study of 55 Cavaliers, the researchers reported that the wider the syrinx, the stronger the predictor of pain, scratching behavior and scoliosis in dogs with syringomyelia. They stated: "Both pain and syrinx size were positively correlated with syrinxes located in the dorsal half of the spinal cord." They also concluded that such pain is likely to be neuropathic pain, resulting from disordered neural processing in the damaged dorsal horn.

Syringomyelia can be very deceptive because some symptoms (which may include paw licking, head shaking, head rubbing, circular walking, fly biting, and reluctance to defecate) are common behaviors for many unaffected dogs. One distinction is that dogs suffering from SM engage in these patterns excessively and seemingly compulsively. So, other causes of the dog's symptoms need to be considered and should be ruled out before concluding that SM is the cause. For example, if a syrinx develops in a lower area of the spine, such as the lumbar region, the dog may scoot excessively, even to the extent of rubbing the anal area raw. However, scooting is a common symptom of other disorders, or even of no particular disorder at all.

Another disorder common to Cavaliers and with symptoms similar to SM is Primary Secretory Otitis Media (PSOM), which is a highly viscous mucus plug which fills the middle ear and causes the tympanic membrane to bulge. Because the pain and other sensations in the head and neck areas, resulting from PSOM, are so similar to symptoms due to SM, the possibility that the Cavalier has PSOM and not SM should be determined before diagnosing SM.

An excellent review of the various symptoms displayed by dogs affected with syringomyelia may be found on the SM.CavalierTalk.com website, prepared by Karlin Lillington of Dublin, Ireland. Her website includes videos of SM-affected dogs. Also, see flycatcher's syndrome for a description of another disorder prevalent in CKCSs and which has identical symptoms to the fly biting of some SM/CM-affected dogs.

The only accurate way of diagnosing the disease is through the use of magnetic resonance imaging (MRI) scanning. Clinic charges for MRI examinations of canines have been known to vary from $400.00 to over $2,000.00. Accurate MRI results require that usually the dog be anesthetized. In view of the high cost of MRI scans, the examining veterinary specialist usually will attempt to rule out other causes of the symptoms first. Veterinarians who perform MRIs of should consider following this MRI Screening Protocol devised by Dr. Rusbridge.

The MRI allows the veterinary neurologist or neurosurgeon to study the skull and spine for the presence of any abnormality which might obstruct the flow of the cerebrospinal fluid. When examined by MRI, the syringomyelia appears as a tubular cavity of fluid, called a syrinx, within the spinal cord. In severe cases, the syrinx is so wide that only a thin rim of the spinal cord is visible. An MRI scan of a dog without any syrinxes at all still may show that the dog has Chiari-like malformation.

The MRI scan of a Cavalier at the right shows the occipital malformation, with the cerebellum being squeezed out of the occipital bone and into the area of the foramen magnum (red-outlined area). It also shows pockets of white cerebrospinal fluid in the spinal cord (yellow-outlined area). See Karen Kennedy's Basic Canine NeuroAnatomy and MRI Imaging Planes, for further information about MRI scans.

In a study conducted by Dr. Rusbridge and Ms. Knowler, in a sample of seventy "unaffected” Cavaliers from Europe and North America, which were MRI-scanned only for breeding purposes, 70% of them had syringomyelia, 17% were "at risk", meaning were young dogs with Chiari-like malformation but no syringomyelia yet, and only 13% were "clear" of both the malformation and SM.

A supplemental diagnostic screening tool used by at least two veterinary neurologists, Dr. Curtis W. Dewey and Dr. Georgina Barone, is the BAER (for Brainstem Auditory Evoked Response) test. The BAER test measures the timing of electrical waves from the brainstem in response to clicks in the ear. Dr. Dewey reports that, assuming the dog is not deaf, the detected brain waves can be used to assess the integrity of the brain stem, since CM involves some degree of brain stem compression.

The following MRI photographs, and their descriptive text, are courtesy of Dr. Clare Rusbridge and Ms. Penny Knowler of Stone Lion Veterinary Centre:

Above: This image shows mild Chiari-like malformation – the cerebellum is very slightly indented, the kinking of the medulla is normal for a toy breed and there is displacement of the cerebellum into and just out of the foramen magnum. The ventricular system is slightly dilated.

Above: Although the cerebellum is not coming through the foramen magnum, this dog has a greater degree of Chiari-like malformation than the first dog. The cerebellum is indented, and the medulla is kinked. The central canal is dilated above the first disc space – this is the first sign of syringomyelia developing. There is also mild ventricular dilatation.

Above: This dog has descent of the cerebellum towards the foramen magnum and the cerebellum is indented. The medulla is normal for a toy breed; there is mild ventricular dilatation and a small syrinx/central canal dilatation in the upper cervical spinal cord.

Progression of SM is extremely variable. Some Cavaliers may exhibit no scratching or pain; others tend to scratch with only mild pain and no other neurological signs. Other CKCSs can be severely disabled by pain and neurological signs within twelve months of the first signs developing.

Treatment options consist of drugs and surgery, as are examined in detail below. Dr. Rusbridge has prepared a diagram of treatment options, which she calls a treatment algorithm, which is downloadable here in pdf format.

Treatment options for CM/SM are very limited. Before the disease progresses to its severe form, the use of anti-inflammatory cortisteroids, such as prednisolone (Prelone), methylprednisolone (Medrol, Medrone), and dexamethasone (Decadron, Dexamethasone Intensol, Dexone, Hexadrol), or non-steroidal anti-inflammatory drugs (NSAIDs), such as carprofen (Rimadyl), Metacam, and aspirin, may relieve the symptoms but not the deterioration. Cortisteroids have serious side effects, such as weight, gait, and skin changes, and harmful suppression of the immune system. Long term use of these drugs is not advised.

NSAIDs and other conventional analgesic medications have not been found to be effective by themselves to relieve pain. Two 2007 studies (1) (2) show that the type of pain behavior suggests that the dogs experience neuropathic pain, probably due to disordered neural processing in the damaged dorsal horn, and that, "as such it is likely that conventional analgesic medication may be ineffective."

Anticonvulsants, such as gabapentin (Neurontin, Gabarone), have been CavalierHealth.org -- Blenheim Company

successful in some more severe cases. Gabapentin works through a receptor on the membranes of brain and peripheral nerve cells. It binds to calcium channels and modulates calcium influx as well as influences GABergic neurotransmission. Its effect is to deaden the irritated nerve impulses in the dog's neck. In humans, gabapentin reportedly does not interact with any other medications, and it is not metabolized, so it is fully excreted in the urine and has no affect upon the liver. However, in dogs, gabapentin is partially metabolized in the liver, and therefore the prescribing neurologist may be expected to order periodic blood tests to check the liver enzymes.

In human studies, gabapentin has caused side effects, including sleepiness, dizziness, and leg edema, which were minimized by increasing the dose gradually and by taking the drug with food. Gabapentin also may be given in combination with NSAIDs.

A newer anticonvulsant, pregabalin (Lyrica), is being prescribed by some neurologists in treating SM. It is closely related to gabapentin and was developed by Pfizer, which also developed gabapentin. Pfizer reports that pregabalin is more potent than gabapentin and achieves its effect at lower doses. Doses of pregabalin also reportedly have a longer lasting effect than gabapentin. No generic version is available, and as an exclusive brand, Lyrica is quite expensive in comparison to generic gabapentin.

Oral opioids (pethidine, methadone, tramadol) are alternatives to anticonvulsants. Methylsulfonylmethane (MSM) is recommended by some veterinary neurologists as a dietary supplement.

Drugs which reduce the production of cerebrospinal fluid, including proton pump inhibitors such as omeprazole (Prilosec, Losec, Zegerid), and the diuretics, furosemide (Lasix, Diuride, Frudix, Frusemide) and spironolactone (Aldactone), are reported to be useful to reduce intracranial pressure. Long term use of omeprazole is not recommended, as it may increase the risk of stomach cancer. Carbonic anhydrase inhibitors, such as acetazolamide (Diamox) also serve to decrease the flow of cerebrospinal fluid, but their adverse side effects of abdominal pain, lethargy, weakness, and bone marrow suppression limit long term use. Researchers have been examining the effects of cimetidine (Tagamet), which is a histamine H2-receptor antagonist -- an antihistamine. Histamine contributes to inflammation and causes smooth muscles to constrict. Cimetidine is diffused into the cerebrospinal fluid and reportedly may contribute to reducing the flow of CSF. When taken with gabapentin, cimetidine also reportedly may increase the amount of gabapentin in the blood by decreasing its elimination. Therefore, when taken together, the dosages may require adjustment.

Some neurologists are prescribing amantadine (Symmetrel), which is used for control of the symptoms of Parkinson's disease in humans, together with gabapentin or pregabalin. Amantadine is believed to release brain dopamine from nerve endings making it more available to activate dopaminergic receptors.

An herbal supplement which Cavalier owners report calms dogs suffering from the symptomatic scratching of SM is a product called "Nerve Eight" or "Nerve 8" (manufactured by Nature's Sunshine of Provo, Utah), which consists of white willow bark (salix alba), black cohosh root (cimicifuga racemosa), capsicum fruit (capsicum annuum), valerian root (Valeriana officinalis), ginger root (zingiber officinale), hops flowers (humulus lupulus), wood betony herb (betonica officinalis), and devil’s claw root (harpagophytum procumbens).

Some owners of SM dogs report that periodic treatments of acupuncture provide relief.

Surgery to allow the cerebrospinal fluid to flow normally may be necessary to reduce the pain and deterioration. Surgery is recommended if there is significant pain or a deteriorating condition. It usually is successful in significantly reducing the pain and improving the neurological deficits. Neurologists experienced with CM and SM in Cavaliers have found that early surgical treatment is more successful than waiting and considering it as a last resort, and that the longer the dog has been in pain, the less likely it will recover.

One form of surgery is called foramen magnum decompression (FMD), or suboccipital decompression, surgery. The surgeon removes the supraoccipital bone and the cranial dorsal laminae of the atlas. Decompression surgery may include incising through the dura sac, a tough membrane which contains the brain inside of the skull, and installing a dural graft or shunt, to allow more space for the cerebellum and to reduce the pressure of the flow of CSF. In some surgeries, the entire occipital bone also is removed. A less frequent surgical procedure is subarachnoid shunting, which essentially is a salvage operation when the surgeon has no other surgical options. All FMD surgeries are technically difficult and should be performed only by experienced neurological surgeons.

Although this form of surgery often is successful, it is very expensive, and many dogs either have a recurrence of the disease or still show signs of pain and scratching. Some post-operative pain is only temporary, due to leakage of CSF through the incision in the dura until that incision heals, or because the syrinx is still present after the surgery. The most frequent reason for recurrence reportedly is the development of post-operative scar tissue which compresses the cervicomedullary junction. Scar tissue has required additional surgery to remove it in as many as half of all FMD surgical cases. To avoid the development of scar tissue, it is important to not allow the dog too much freedom of movement or excitement during the healing process, which may last from three to six months.

Copyright © 2007 Long Island Veterinary Specialists

Dr. Curtis W. Dewey, veterinary neurologist in New York, and Dr. Dominic J. Marino, board certified veterinary neuro-surgeon, also in New York, and Dr. Wayne L. Berry, veterinary neurologist in California (and perhaps other specialists) have been inserting a skull plate made of titanium mesh at the junction before closing the incisions in several surgeries thus far (see photo), in an effort to prevent such scar tissue from re-compressing the junction. This procedure is called cranioplasty. In a report published in July 2007 in Veterinary Surgery, Drs. Dewey and Marino wrote: "Foramen Magnum Decompression (FMD) with cranioplasty was well tolerated, with no intraoperative complications, and minor postoperative complications. Most dogs improved clinically, and none required further surgery at the original FMD site." Dr. Dewey also has reported that the "re-operation rate" has been reduced to 10% or less of all FMD surgeries with the titanium mesh cranioplasty. See more about Drs. Dewey and Marino under Current Research below.

Decompression surgery is not expected to cure the SM. It is intended to reduce the pressure and stop the progression of the syrinxes. Damage done to the brain and spinal cord before the surgery usually will not be reversed, and most dogs will need to continue on medications afterwards, including gabapentin or pregabalin and cortisteroids, depending upon the severity of that damage before the surgeries. The neurologists also may recommend that the post-surgery patient undergo rehabilitation physical therapy, in part to offset debilitating effects to the muscles, which may result from long term doses of cortisteroids.

Another form of surgery, performed by veterinary neurosurgeon Geoffrey Skerritt, BVSc DipECVN FRCVS, in the United Kingdom, involves inserting a shunt, rather than removing the supraoccipital bone or a portion of the atlas. He is said to prefer the shunt because it reduces the higher risk of nerve damage and blood loss in decompression surgery, and it lessens the possibility of the cerebellum continuing to herniate. Mr. Skerritt may be contacted at Chase Lodge, Welsh Road, Childer Thornton, South Wirral, Cheshire CH66 5NU, telephone 0124 485 3823, email GCSkerritt@aol.com.

These studies all have been "case studies", meaning that they were practiced without the controls normally included in clinical trials. In the July 2007 issue of Veterinary Surgery, Dr. Richard A. LeCouteur, board certified veterinary neurologist at the University of California, writes that "Medical history is replete with examples of invasive procedures and pharmacologic interventions that were widely accepted based on results of case studies, only to later be rejected based on results of controlled clinical trials. ... It’s time to adopt a more structured scientific approach to the study of the management of neurologic conditions that may benefit from surgical intervention. The randomized (preferably) double-blinded (preferably) placebo-controlled study is the gold standard for evaluating a new treatment intervention."

-- post-surgery soundwave therapy

At least one Cavalier King Charles spaniel, which continued to suffer severe pain due to post-decompression surgery scar tissue, recently has been very successfully treated with an infrasonic instrument called AlphaSonic™. This infrasound technology generates multiple, random, chaotic sound waves in the range of Alpha (approximately 8 to 14 Hz), and unlike ultrasound waves, does not heat body tissue. Ultrasound uses a single high frequency (from 20,000 to1,000,000 Hz) to stimulate a localized area and heats tissue.

The manufacturer of the device represents that AlphaSonic™ is safer and more effective than ultrasound, penetrates deeper into the tissues, reduces inflammation, and softens scar tissue. It can be applied locally and at acupressure points, and is said to increase blood circulation and can allow the body to heal itself, much like the affects of acupuncture, but without the needles.

The device is electrically operated and looks very similar to an ultrasound unit. Dr. Ronald J. Riegel, DVM, who has studied the effects of the AlphaSonic™ since 2001, stated, "The goal of any physical therapy modality is to increase the circulation and increase the elasticity and flexibility of the tissue. the alphasonic absolutely increases circulation and allows the body to heal itself. The metabolism is increased, reducing recovery times".

Adequate hydration is important for optimum bodily function. The dog should be kept hydrated before, during, and after treatment with fresh clean water. Although the manufacturer reports that AlphaSonic™ is totally safe and that no negative side effects are known, any AlphaSonic™ treatments for dogs with veterinary conditions, especially those taking medication, should be performed only under the guidance of a qualified, licensed veterinarian. For more information about AlphaSonic™, contact Susan Stoltz at AlphaSonic, P.O. Box 2727, Valley Center, CA 92082, telephone 760-751-2836, email alphasonics@sbcglobal.net, website www.alphasonic.com

4New therapeutic agent to provide improved pain relief. The Clinical Investigation Center at the University of Minnesota College of Veterinary Medicine is conducting a 14-day study of CM/SM in Cavalier King Charles spaniels. The project will examine treatment with a new therapeutic agent which is hoped to provide improved relief from the pain associated with this condition. Before a CKCS can be enrolled in the study, it will need to have been diagnosed by MRI scan with CM/SM within the last 8 months. This evaluation can be performed at the University of Minnesota Veterinary Medical Center. Additionally, prior to enrollment, the dog must have some clinical signs of scratching, pain, and sensitivity to touch. Cavaliers aged from 1 year to 11 years and weigh between 8.8 lbs. and 28.6 lbs. to eligible. Dogs currently on other pain medications are still eligible but we will have a transition period to wean them off current therapies. Dogs intended for breeding or with concurrent medical conditions including ear disease, grade 3 to 5/6 MVD heart murmur, or epilepsy are not eligible for the study. The initial neurological evaluation is offered free of charge, and and if eligible for study enrollment, the MRI is also free of charge.

Dogs enrolled onto this study will be randomly allocated the new therapy or placebo, in a 1 to 1 ratio. A placebo is a product which looks like the investigational product, but contains no active ingredient. You and the veterinarian will not know which treatment your dog is receiving; this is known as a “masked” study. This helps the accuracy of the drug evaluation. The dog will still receive basic pain medication with carprofen (Rimadyl®) regardless of whether they are taking the new drug or the placebo.

Once the diagnosis of syringomyelia has been confirmed by MRI, a blood sample will be taken to determine if the dog is in good general health. Participating Cavaliers will be prescribed carprofen (Rimadyl®) and will need to take this treatment twice daily for a minimum of 7 days prior to enrollment on the study. The dog will then need to return to the Veterinary Medical Center to be enrolled in the study and will be assigned either the new therapy or placebo. The dog will take this medication twice daily in addition to the carprofen for 14 days. There would be two further follow-up visits- one after 7 days of treatment and one after 14 days of treatment (end of study visit).

The principal investigator is Dr. Ned Patterson. For more information, contact Marianne Robeck, study technician, telephone 612-624-1352, email robec008@umn.edu website www.cvm.umn.edu/cic/current/Neurology/Syringomyelia.html (May 2008)

4Evaluation of a new medication to manage the pain and discomfort associated with syringomyelia. Veterinary Clinical Investigation Center at the Matthew J. Ryan Veterinary Hospital of the University of Pennsylvania is conducting a Syringomyelia Clinical Study for the treatment of neuropathic pain in Cavalier King Charles spaniels. Cavaliers that have any of the following symptoms: neck pain, sensitivity to touch, or scratching at the head and neck and have been diagnosed with, or is suspected of having Chiari-like malformation (CM), syringomyelia, or occipital hypoplasia, may be eligible to participate in the study.

The study will run over the course of one month and may require five or six visits to the Ryan Veterinary Hospital. Following the consult with the neurologist, all dogs will receive an MRI. All study participants will initially be prescribed Rimadyl® and then randomized to either the study medication or placebo which they will take for two weeks. Upon completion of the study, the neurologist will discuss any other options and considerations with the owner as well as set up a long-term pain management regimen.

For more information, contact Dana W. Durso, RN, Veterinary Clinical Investigation Center, telephone 215-573-0302, email vcic@vet.upenn.edu (May 2008)

4Transcranial Magnetic MEP to assess motor and sensory pathways in Cavaliers' spinal cords. Drs. Roberto Poma and K. C. Wolfe of the Ontario Veterinary College, University of Guelph, in Ontario, report they are conducting a study to assess the functional integrity of the descending (motor) and ascending (sensory) pathways in CKCS dogs with magnetic resonance imaging of cervical spinal cord and brain suggestive of SM and Chiari-associated SM

They state: "Stimuli applied to the scalp can excite the motor pathways, inducing muscle action potentials from fore- and hind limbs. A motor evoked potential (MEP) can be elicited by transcranial magnetic stimulation. Transcranial Magnetic MEP (Transcranial Magnetic Motor Evoked Potential) is not painful and can be performed with or without sedation. ... In veterinary medicine especially, TMMEP has been used to assess the correlation between severity of clinical signs and motor evoked potentials (MEP) in large-breed dogs with cervical spinal cord diseases, in Doberman Pinscher with cervical vertebral instability and in chondrodystrophic breeds with intervertebral disc disease. ... In CKCS dogs with clinical signs of SM, intermittent neck pain is the most common neurological sign observed. The pain is likely to be multifactorial and related to obstruction of CSF flow and spinal cord damage. Damage to the dorsal horn of the spinal cord is a key feature in the chronic pain of SM The dorsal horn of the spinal cord is the most important relay center for transmission of sensory information to the brain. Somatosensory evoked potentials of the cervical spinal cord were performed in human patients affected by SM. Abnormal SEP latencies were detected in patients with neck pain supporting a sensory etiology affecting the cervical spinal cord of dogs affected with SM."

Drs. Poma and Wolfe may be reached at telephone 519-824-4120, ext. 54129, email rpoma@uoguelph.ca (March 2008)

4"Radiographic morphology of the cranial portion of the cervical vertebral column in Cavalier King Charles Spaniels and its relationship to syringomyelia". Researchers at the Department of Veterinary Medicine, University of Cambridge, England (Stalin CE, Rusbridge C, Granger N, Jeffery ND) published in January 2008 a report of their study to compare radiographic morphology of the atlantoaxial region between Cavaliers and other breeds and determine whether there was an association between radiographic morphology of the atlantoaxial region and syringomyelia in CKCSs. Sixty-five Cavaliers and 72 other dogs were examined. The result was that "the amount of overlap of the atlas and axis and the relative size of the spinous process of the axis were significantly smaller in CKCSs than in dogs of other breeds. However, the amount of widening of the atlantoaxial joint that occurred when the neck was moved from a neutral to a flexed position was not significantly different between groups, and no association was detected between syringomyelia and excessive atlantoaxial joint space widening or between syringomyelia and an excessively small axial spinous process." They concluded "that these differences do not account for why some CKCSs develop syringomyelia and others do not." (January 2008)

4Study of the treatment of neuropathic pain associated with syringomyelia in Cavalier King Charles Spaniels. The Royal Veterinary College of the University of London is conducting a clinic trial, beginning in November 2007, to assess the therapeutic value of a novel pharmacological agent in CKCSs with syringomyelia. Dogs enrolled onto the study will be treated with this novel agent, given orally, for 14 days. The researchers anticipate that the novel agent will ease clinical signs and offer a therapeutic advantage over current analgesic remedies. Eligibility Requirements: CKCS with SM confirmed by a MRI within 8 months prior to enrollment; clinical signs of: scratching, pain, sensitivity to touch; dogs must weigh 4Kg-12Kg; dogs must be aged 1yr – 10yrs; dogs currently on other pain medications are still eligible but a changeover program will be implemented.

Participating dogs will receive free MRIs, CSFs, pre-anaesthetic blood profiles, and neurological evaluations if not been performed in the last 8 months. As a post study incentive, a veterinary care voucher will be given and may be used towards treatment of the condition. Contact: Clinical Investigation Centre, Veterinary Clinical Sciences, Royal Veterinary College, Tel: (01707) 666605, email: cic@rvc.ac.uk. (November 2007)

4"The search for the gene(s) predisposing to Chiari 1 malformation with syringomyelia." At the International Symposium on Syringomyelia held in October 2007 in Rugby UK, Dr. Guy A. Rouleau, (M.D., Ph.D., Director , Centre for the Study of Brain Diseases, Montreal, Canada) reported: "Pedigree analysis in a large database of over 5,500 CKCS has suggested that Cm/SM is inherited where all clinically affected dogs share a small number of common ancestors. To date, no genetic factor predisosing to CMI has been identified in either humans or dogs.

He further stated: "The CKCS is the only known naturally-occurring animal with a high frequency of CMI. We constructed a genealogy of more than 10,600 related CKCS dogs spanning 24 generations across 3 continents (North America, Australia, and Europe) from over 600 MRI confirmed dogs. A molecular genetic study of 173 CKCS dogs identified six chromosomal regions with potentionally significant results: chromosomes 3, 5, 9, 11, and 15. We are currently performing additional studies in additional dogs. Confirmed chromosomal regions will be further studied, with the aim of identifying the causative mutation(s) and gene(s). Identification of the CM/SM gene(s) will allow the development of a genetic test for the identification of carriers for breeding purposes with the ultimate aim of reducing or eliminating this devastating condition in the CKCS breed." (October 2007)

4Alternatives to MRI Scans: Dr. Curtis W. Dewey, board certified veterinary neurologist and board certified veterinary surgeon, Cornell University in Ithaca, New York, and Dr. Dominic J. Marino, board certified veterinary neuro-surgeon and chief of staff at Long Island Veterinary Specialists (LIVS) in Plainview, New York, Dr. Georgina Barone (board certified veterinary neurologist), and other specialists at LIVS also have been researching the possible use of the brain stem auditory evoked response (BAER) test, infrared thermography (IRT), and helical (spiral) computed tomography (CT), as screening tools for identifying adult CKCSs with CM. BAER is a clinical electro-diagnostic tool used to evaluate hearing ability as well as the functional integrity of the brain stem.

In an October 2007 update, Dr. Marino reported that 38 Cavaliers had been evaluated thus far. Of those, one dog had a normal MRI, BAER, and thermographic evaluation; 23 dogs without clinical signs of SM had abnormal MRI findings, with 16 of those 23 dogs (69.6%) also having abnormalities with BAER testing; and 14 dogs with clinical signs of SM had abnormal MRI findings, and 13 of those 14 dogs (92.8%) also had abnormal BAER tests. He concluded that “BAER testing may play a more useful role in screening ‘clinical’ dogs rather than dogs without clinical signs.”

Dr. Marino also reported that each dog was imaged with thermography, both awake and under general anesthesia. He stated that the complete analysis of thermal patterns is on-going, but that preliminary results revealed “cooler” thermographic patterns in dogs with abnormal MRI findings compared with the one dog with a normal MRI. Magnetic resonance imaging findings were classified as mild, moderate, and severe correlated with thermographic findings, 100%, 50%, and 0% of the time respectively. Based on these very preliminary findings, Dr. Marino concluded in his October 2007 report that "thermography may be a viable imaging modality to use as a screening tool to detect CLM in dogs." Dr. Marino may be contacted at telephone 516-501-1700, email Bongorno@aol.com LIVS's website is www.LIVS.org. (October 2007)

4Association between frontal-sinus size and SM: Dr. Dewey and others (Drs. Peter V. Scrivani, Margret S. Thompson, Kevin R. Winegardner, and Janet M. Scarlett) report in a June 2007 article of a study of 62 dogs (four of them were CKCSs) that there may be an association between frontal-sinus size and SM in Cavaliers and other small-breed dogs. They state: "Our data do suggest, however, that the pathogenesis of syringohydromyelia in small-breed dogs may involve the supratentorial portion of the cranial cavity. We postulate that syringohydromyelia develops in many small-breed dogs and certain breeds in particular as a result of global malformation of the entire cranial cavity or supratentorial portion of the cavity and is not limited to the infratentorial portion of the cranial cavity. If this is true and results can be generalized to the target population, our understanding of the pathogenesis of syringohydromyelia in small-breed dogs and several aspects of clinical management (e.g., screening and diagnostic testing, breeding recommendations for dogs with dome-shaped heads, and treatments) will require further investigation." (June 2007)

4Study of possible correlation between head shape and CM/SM in Cavaliers and other toy breeds. Dr. Rusbridge and Ms. Knowler report in their April/May 2007 Research Newsletter the the preliminary results of pilot study looking at the possible correlation between head shape and CM/SM in different toy breeds. They report: "In response to some observations made by breeders on head shape, a simple pilot study was devised. Dogs were selected on the basis of head length/breadth ratio, degree of doming, and presence or absence of a ski-slope shape to the back of the head. CM/SM status was confirmed by MRI. Early results of this pilot study found no correlation, however the investigation is still ongoing. This study has been a tremendously valuable exercise in other ways. On the basis of head shape, some dogs had been presumed to be affected, and owners had originally elected against MRI screening. However some of these dogs were actually found to be free of the condition. This suggests that it is not yet possible to predict CM/SM by a visual assessment of head shape. It also provided the opportunity to obtain blood DNA samples for the Genome study in Montreal. In particular, we would like to thank Lee Pieterse for co-ordinating the project in Australia. She and her husband Frank also contributed $4000 towards the research. Sandy Smith in Canada, generously donated $8000 from the ‘For the Love of Ollie’ Fund. An additional sum of $4000 came from the ‘Syringomyelia DNA Research’ Fund. Total $16,000." Donate to For the love of Ollie or directly to SM DNA Research! (May 2007)

4Geneticist to Research SM Breeding Protocol: Dr. Rusbridge and Ms. Knowler report in their Syringomyelia News 2007 Research Update that Dr. Sarah Blott MSc PhD of the Genetics Department at the Animal Health Trust has joined the CM/SM research team. Dr. Blott is a geneticist with a particular interest in developing breeding schemes for companion animals. She combines state-of-the-art knowledge in quantitative genetics with molecular genetic markers.

4Full Genome Scan & Genetic Mapping: Dr. Rusbridge and Ms. Knowler reported in August 2005 that their study of Cavalier King Charles spaniels diagnosed with syringomyelia has shown that the disease is a common condition in Cavaliers and appears to be more severe and have an earlier onset with increased inbreeding, especially when breeding from affected dogs. They have been leading a successful effort to collect DNA from thousands of Cavaliers from throughout the world, to conduct a survey to identify DNA markers. In an April 2006 research update, Dr. Rusbridge reports that "a full genome scan looking for the causal gene/s of syringomyelia and mitral valve disease is underway!" (A Dr. Clare Rusbridge video DVD "Syringomyelia Seminar" is available by contacting penny.knowler@ntlworld.com ). The Cavalier Health Foundation (associated with the Cavalier King Charles Spaniel Club, USA) has contributed a grant to help underwrite this project. Donate to the Cavalier Health Foundation and For the love of Ollie or directly to SM DNA Research!

Also participating are Marie Pierre Dube, a genetics epidemiologist at the Montreal Heart Institute, and Dr. Zoha Kibar, the molecular geneticist in charge of fine mapping and identification of the gene(s) defective in SM in CKCSs, at the Centre for the Study of Brain Diseases, CHUM – Montreal. The study is searching for recessive genes which may be the cause of the disease. The researchers suspect that the disorder is not due to a simple recessive gene, but rather a complex trait. Their future plans include genotyping, linkage disequilibrium analysis gene mapping, and positional candidate gene cloning.

Dr. Kibar commented about her current gene study, as follows: "Breeders should understand that our study will not be the magic solution that will help them identify dogs that will not develop SM for breeding purposes (at least not in the short term). But identifying a gene will open the door to understanding pathways involved in the development of this disease and hopefully in the long run, a cure for these suffering dogs. Of course we are also interested in the biology. Irrespective of the complexity we are dealing with, we have to try to understand the disease with the tools we have and hence the genetic approach. And irrespective of this complexity, and if we don’t want to think about the multifactorial etiology, the breeding protocol scheme Dr. Rusbridge came up with is the best solution for now. Then later we can deal with the causes."

In the April 2006 update, Dr. Kibar reports:

    "Both Syringomyelia and Mitral valve disease are particularly common in the Cavaliers. Such high incidence in a particular breed as compared to other breeds suggests the involvement of genetic factors. The mode of inheritance including the number, identity and relative contribution of the causative genes is not determined yet. The etiology of both conditions could be further complicated by variable penetrance of the various genotypes and the involvement of environmental factors.

    "The first step which is genetic mapping is currently underway. Due to the complex inbreeding in the CKCS, a preliminary genetic analysis was necessary to evaluate the informativeness of the genetic markers and hence the feasibility of a whole genome scan in such breed. Consequently, 10 dogs were selected for genotyping with 122 markers distributed among the 38 autosomes and X chromosome. The markers were found to be sufficiently polymorphic and informative. Next, 200 dogs were selected for a whole genome scan, primarily for Chiari malformation. However with additional phenotypic information on mitral valve disease, it is possible to use the same data to map the gene(s) defective in this disease. The whole genome scan was conducted at the Mammalian genotyping Center [Center for Medical Genetics] at the Marshfield Clinic in Wisconsin, USA. The genotyping data will now be analyzed using both linkage-based and association studies. In the latter, we will be taking advantage of the founder effect demonstrated for both these disorders in the CKCS breed.

    "This strategy involves: 1) genetic mapping of the underlying gene(s), 2) identification of these defective gene(s) using the positional candidate gene approach and characterization of the mutation(s) and 3) initial functional characterization of the protein(s) encoded by the gene(s). This will help better understand the underlying pathogenic mechanisms for better diagnosis, prognosis and clinical management of these devastating conditions. These studies will also help unravel some of the complexity involved in this malformation in humans and in the embryonic development of the affected structures."

Canadian physicians and researchers Dr. Guy A. Rouleau, at McGill University, and Dr. Berge Minassian, at the University of Toronto also are participating in this research. Drs. Rouleau's and Minassian's experience includes having isolated the canine gene deemed responsible for Lafora's disease, a form of epilepsy. Dr. Clare Rusbridge and Penny Knowler may be reached at Stone Lion Veterinary Centre, 41 High Street, Wimbledon, London, SW19 5AU, telephone 0208 946 4228, email Dr. Rusbridge neuro.vet@btinternet.com email Ms. Knowler penny.knowler@ntlworld.com

4Development of Clinical Signs and CSF Flow: Dr. Natasha J. Olby, board certified veterinary neurologist, and Dr. Sofia Cerda-Gonzalez, both at North Carolina State University's College of Veterinary Medicine's Department of Clinical Sciences, reported in June 2006 that they and team members at IAMS Pet Imaging Center, Raleigh, NC. are in the process of conducting a three year study to determine whether abnormalities of the caudal fossa and cervical spine predict future development of clinical signs of SM.

The NC State/IAMS Pet Imaging Center team also has been studying the dynamics of cerebrospinal fluid flow in Cavalier King Charles Spaniels, and the extent to which head positions of the dogs affect the flow patterns. They reported in June 2006 finding that turbulent flow occurs in dogs with SM and can be found within syrinxes, and that CSF flow velocity may be higher within the dorsal subarachnoid space of affected dogs. They stated that additional studies are needed to determine whether their findings are significant. For more information, go to http://www.cvm.ncsu.edu/docs/neuro_studies.html or contact Dr. Cerda-Gonzalez at scerdag@ncsu.edu. (June 2006)

4Progression of SM as Puppies Grow: Dr. Curtis W. Dewey, board certified veterinary neurologist and board certified veterinary surgeon, Cornell University in Ithaca, New York, is planning to begin a project of repeated MRI scanning of litters of Cavalier King Charles spaniel puppies to identify the prevalence of Chiari-like malformation in the breed, and its progression as the puppies grow. For more information, contact Dr. Dewey at cwd27@cornell.edu

4Ultrasound As SM Detector: Dr. Amy S. Tidwell, board certified veterinary radiologist, at the Cummings School of Veterinary Medicine at Tufts University in Massachusetts, is researching the use of ultrasonography to diagnose syringohydromyelia in dogs, with Drs. Dominik Faissler and John McDonnell. In a 2005 interim report, the researchers stated, "This preliminary study indicates that cervical spinal cord ultrasound can be useful as a diagnostic aid for CM. It cannot rule out a diagnosis of CM, however no false positives were found. To investigate the sensitivity and specificity of this imaging modality blinded U/S examination of large numbers of dogs after MRI evaluation is planned." For more information, contact Dr. Tidwell at amy.tidwell@tufts.edu

4Positioning for MRIs: In April 2006, the Cavalier King Charles Spaniel Club, UK announced that it will be funding research into whether the positioning of the dog's head in the MRI's receiving coil influences the accuracy of the resulting MRI scan of the dog's brain and spinal canal. Dr. Rusbridge and Dr. Nick Jeffery, BVSc PhD CertSAO DSAS (soft tissue) DECVN DECVS FRCVS, at the University of Cambridge's Department of Veterinary Medicine, in Cambridge, England will be conducting this project. This research is expected to lead to greater accuracy and uniformity in MRI scans of dogs with CM and SM. For more information, contact Dr. Rusbridge at Stone Lion Veterinary Centre, 41 High Street, Wimbledon, SW19 5AU, telephone: 00 44 208 9464228, email neuro.vet@btinternet.com or Dr. Jeffery at telephone 01223 337621, email ndj1000@cam.ac.uk (April 2006)

4Repeated MRIs Study: In March 2006, the Cavalier King Charles Spaniel Club of Canada (CKCSCC) announced plans for a syringomyelia research project to be conducted by Dr. Roberto Poma, DMV, DVSc, ACVIM Neurology, Assistant Professor, Department of Clinical Studies, Ontario Veterinary College. Participating Cavalier King Charles Spaniels first will undergo a preliminary examination, including blood work, by Dr. Poma to determine eligibility for the project. Once accepted, the dogs will have MRIs at a cost of about $600.00 (Canadian). The preferred age of participating Cavaliers is as young as 5 1/2 months. A second evaluation will be conducted 3.5 years. However, depending on the findings of the first MRI, the dog may be examined again at 1.5 years and then again at 3.5 years. As group of older dogs, over age 3.5 years, also may be included, with their data collected as a subset grouping. Anyone interested in having their Cavaliers participate in this program should contact Pat Barrington of the CKCSCC's Health & Education Committee to receive a questionnaire or for more information. Her email address is harley2@sympatico.ca (March 2006)

4Post-mortem studies of Cavaliers: Owners of deceased Cavalier King Charles spaniels, which had been diagnosed with syringomyelia or Chiari-like malformation are urged to donate their dogs' bodies to researchers for post-mortem studies to enable the designing of a protocol for dealing with pathological material. Any owners interested in contributing their late Cavaliers to SM research should contact any of these researchers: Dr. Nick Jeffery, Department of Veterinary Medicine, University of Cambridge, Madingley Road, Cambridge, CB3 OES, telephone 01223 337621, email ndj1000@cam.ac.uk; Dr. Jim Anderson, Glasgow University, email Gvsa07@udcf.gla.ac.uk; Dr. Rodolfo Cappello, The Royal Veterinary College, University of London, email RCappello@RVC.AC.UK; or Dr. Curtis Dewey, Cornell University, email cwd27@cornell.edu The nervous system degenerates rapidly after death and must be handled appropriately, so please contact these researchers as soon as or ideally before the dog has been euthanatized.

4Fetal and neonatal specimens of Cavaliers: Dr. Imelda McGonnell of the Department of Veterinary Basic Sciences, The Royal Veterinary College, is leading a study looking at anomalies in different stages from the Cavalier's early growth in the uterus to its maturity. The study needs aborted fetuses and deceased young puppies that die for any reason. Owners williing to participate should contact Sheena Stevens in Devon, UK, telephone 01884 821080, email Kilnshena@hotmail.com The nervous system degenerates rapidly after death and must be handled appropriately, so please contact Ms. Stevens as soon as or ideally before the dog has been euthanatized.

4International Symposium on Syringomyelia held October 23, 24, 25, 2007 in Rugby UK, sponsored by The Ann Conroy Trust, with the University of Birmingham, the Society of British Neurological Surgeons, and the Spine Society of Europe. Summaries of presentations by Clare Rusbridge, Dominic Marino, Graham Flint, Guy Rouleau, and Sarah Blott are available at www.syringomyelia2007.org/symposium07_supplement.pdf. Obtain compact discs of all five talks and the hour long Q&A session with leading experts on syringomyelia and the Chiari-like malformation in cavaliers, for a contribution to support CKCS genome research at http://www.cafepress.com/cavaliertalk/4311456

4Syringomyelia International Conference held November 11, 2006 at the Royal Veterinary College: Read summaries of presentations by Clare Rusbridge, Paul Mandigers, Laurent Cauzinille, Harvey Carruthers, Nick D. Jeffery, Catherine A. Loughin, Martin Deutschland, Dominic J. Marino, and G. Flint, and view their slide presentations.

SM has a tendency to be more severe in each subsequent generation, and with an earlier onset. Breeders should follow the SM Breeding Protocol .

A website devoted to syringomyelia in Cavaliers is Karlin Lillington's SM.CavalierTalk.com

A website and a book about a Cavalier diagnosed with syringomyelia is For the love of Ollie.

Webpages from Laura Lang's CKCS Info Center website, showing additional MRIs and x-rays of SM-affected or CM Cavaliers:

Mechanism of the decrease in intracranial pressure as affected by furosemide. Pinegin LE, Dolzhenko DA, Natochin IuV. Biull Eksp Biol Med 1984;98:682–685.

Furosemide lowers intracranial pressure by inhibiting CSF production. Lorenzo AV, Hornig G, Zavala LM, et al. Z Kinderchir 1986;41(Suppl 1):10–12.

Dorsal notch of foramen magnum due to incomplete ossification of supraoccipital bone in dogs. Watson, A.G., De Lahunta, A., and Evans, H.E. J. Small Anim. Prac. 1989 30:666-673.

Effect of histamine H2 receptor antagonists on the secretion of cerebrospinal fluid in the cat. Naveh Y, Kitzes R, Lemberger A, Ben-David S, Feinsod M. J Neurochem. 1992 Apr;58(4):1347-52.

Occipital dysplasia and associated cranial spinal cord abnormalities in two dogs. Rodney S. Bagley, Michael L. Harrington, Russell L. Tucker, Ronald D. Sande, Charles R. Root, Robert W. Kramer. Vet. Rad. & Ultra. Sept 1996; 37(5): 359.

Persistent scratching in Cavalier King Charles spaniels. Rusbridge C. Vet Rec. Aug 1997;141(7):179.

A syndrome of syringomyelia in the cavalier King Charles spaniel, and its treatment by syringo-subarachnoid shunting. Skerritt GC, Hughes D: In Proceedings from the 12th Annual Symposium of the European Society of Veterinary Neurology, Vienna, 23: 1998.

Syringohydromyelia in Cavalier King Charles spaniels. Rusbridge C, MacSweeny JE, Davies JV, Chandler K, Fitzmaurice SN, Dennis R, Cappello R, Wheeler SJ. J Am Anim Hosp Assoc. 2000 Jan-Feb;36(1):34-41.

Chiari 1/syringomyelia complex in a King Charles Spaniel. Churcher RK, Child G. Aust Vet J. 2000 Feb;78(2):92-5.

Dorsal dens angulation and a Chiari type malformation in a Cavalier King Charles Spaniel. Bynevelt M, Rusbridge C, Britton J. Vet Radiol Ultrasound. 2000 Nov-Dec;41(6):521-4.

Primary secretory otitis media in the Cavalier King Charles spaniel: a review of 61 cases. Stern-Bertholtz W.; Sjöström L.; Wallin Håkanson N. J Small Anim. Prac., June 2003, 44(6): 253-256(4).

Hereditary aspects of occipital bone hypoplasia and syringomyelia (Chiari type I malformation) in cavalier King Charles spaniels. Rusbridge C, Knowler SP. Vet Rec. Jul 2003;153(4):107-12.

Neurological signs and results of magnetic resonance imaging in 40 cavalier King Charles spaniels with Chiari type 1-like malformations. Lu D, Lamb CR, Pfeiffer DU, Targett MP. Vet Rec. Aug 2003;153(9):260-3.

Sound Wave Therapy Not So Shocking. Kate Chope, José M. García-López. Tufts Vety School, Dec 2003 Case Report. http://www.tufts.edu/vet/vet_common/pdf/petinfo/dvm/case_dec2003.pdf

Caudal occipital malformation syndrome in dogs. Dewey CW, Berg JM, Stefanacci JD, et al. Compend. Contin. Educ. Pract. Vet. 2004:26:886-896.