Health Matters » Syringomyelia
What Is Syringomyelia?
Syringomyelia is disorder that causes a cyst or syrinx to form in the spinal cord. A syrinx gets wider and longer over time destroying part of the spinal cord.
How does this syrinx form?
In the normal body there is a flow of fluid which moves steadily around the brain and through the spinal cord. This fluid is called cerebral spinal fluid. A syrinx will form when there is a blockage of this flow. One of the most frequent conditions that will cause this flow interference is when the bone at the back of the head (known as the occipital bone) is too small . This is called a ‘Chiari malformation”. This malformed bone changes the shape of the skull and the brain can be compromised for space. The brain may push through the hole at the base of the skull( known as the foramen magnum). A brain that extends beyond the foreamen magnum will obstuct this hole.This results in blocking of the normal flow of cerebral spinal fluid and can create a syrinx the spinal cord.
What are the signs and symptoms?
A dog affected with Syringomyelia will scratch at the air around the neck area (air or phantom scratching) without connecting with the skin. This is most often observed when the dog is walking on a lead. The dog will continue these behaviours after ear or skin infections have been ruled out by a qualified veterinarian. The dog may at times cry out or yelp with no apparent reason. The dog may also show weakness in the front or rear legs. The symptoms can be observed intermittently and may worsen over the course of a few months or years. An affected dog may also show no visible symptoms and go undetected.
How is Syringomyelia diagnosed?
No one can simply look at a dog and diagnose it. At this time there is no blood test for syringomyelia. An x-ray cannot show the tissue and fluid around the spine or brain. An MRI is the definitive diagnostic tool for determining if a dog has Syringomelia. An MRI can show individual transverse photos (similar to slicing a loaf of bread) of the spine so a syrinx or anomalies at the foramen magum can be easily identified.
What is the treatment?
The primary intention of medical management is to reduce the dog’s pain. Medication options include treatment with NSAIDs (Non steroidal anti-inflammatory drugs). Diuretics that reduce the production of cerebral spinal fluid may be prescibed. Anticonvulsant therapy may be considered as it has been used successfully for pain mangement in affected dogs. Medical management will treat the pain associated with syringmyelia. However, it will not treat the underlying cause.
Surgical intervention can be done. It is a complex procedure by a neurologist to alleviate the the crowding of the brain. This can be done by either removing some or all of the occipital bone. A shunt procedure may also be indicated.
Why do so many Cavaliers have this disease?
It is important to note that syringomyelia is not isolated to a "Cavalier disease". The Chiari malformation can be an inherited condition. Cavaliers are commonly identified as having the Chiari malformation. The malformation does not always develop into syringomeylia. At this time Cavalier owners are actively participating in research and detection. This results in more Cavaliers being identified by definitve MRI diagnosis.
This neurological disorder affects many different breeds of dog. Some of the known affected breeds are the Brussels Griffon, Boston Terrier, Yorkshire Terrier, Cavalier King Charles Spaniel, Chihuahua, French Bulldog, King Charles Spaniel, Maltese, Pomeranian, Staffordshire Bull Terrier, Hungarian Vizsla, Weimaraner, Rhodesian Ridgeback and Poodle.
Syringomyelia is also a human disorder that is increasing in identification.
The Human Side of Chiari and Syringomyelia
(© Copyright 2008, The Royal Spaniels, Volume 13, Number 3; Author: Tammi Brown)
What is being done to help Cavaliers?
Many many Cavaliers live long and healthy lives. That is the wish of everyone who has ever loved a Cavalier. At this time there is no guarantee that a Cavalier will not develop the disease. Due to the genetic incident of this disease it is advisable to avoid dogs with closely related pedigrees. Strategies to attempt to reduce the incidence of syringomelia continue to be developed.
The following articles explain MRI testing:
Basic Canine Neuro Anatomy
Understanding Canine Chiari Malformation and Syringomyelia
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