Syringomyelia (SM) in Dogs

The breeds that are most often affected include the Cavalier King Charles Spaniel and Griffon Bruxellois, but other breeds have been reported as well. Some of these breeds are the Staffordshire Bull Terrier, Boston Terrier, Havanese, Affenpinscher, Pomeranian, Papillon, Chihuahua, Yorkshire Terrier, and Maltese Terrier. This is a serious disorder that needs to be addressed by a veterinary professional right away.

Syringomyelia (SM) in dogs is a relatively common condition that mostly affects Griffon Bruxellois and Cavalier King Charles Spaniels, leading experts to believe it is an inherited disorder. The nature of this disease is that the dog’s skull is too small for his brain, which blocks the opening at the base of the skull and prevents the flow of spinal fluid. Because of this backup of fluid, pockets of fluid called syrinxes are created in the spinal cord which causes extreme pain in the shoulders, neck, head, and chest. They are usually very sensitive to touch in these areas and some dogs show weakness of extremities and possible paralysis.

The signs of syringomyelia depend on the stage of the disease and age of your dog. In fact, some dogs with mild SM may never have symptoms and the only way you will know about the condition is if your dog has to get an MRI for a different reason. However, the most commonly reported symptoms include:

• Extreme sensitivity to touch in the neck, chest, shoulders, head, and back
• Holding head high and at a certain angle to prevent pain
• Sleeping with head held up
• Whining and yelping for no obvious reasons
• Phantom scratching (scratching about an inch or two from the head)
• Weakness of the extremities
• Inability to play or walk
• Depression
• Irritability
• Paralysis
• Seizures

Types

There are several grades of SM, which include:

• Grade 0 - Normal (with no syrinx or pre-syrinx and is not dilated)
• Grade 1 - Central canal dilation (CCD) under two millimeters
• Grade 2 - Syringomyelia (has CCD of more than 2 millimeters and a pre-syrinx or syrinx)

In addition, each grade includes a letter corresponding with the dog’s age because SM is a progressive condition. The letters include:

• A - more than five years old
• B - three to five years old
• C - one to three years old

This system is important for an individual's diagnosis but also for the breeding population. Breeding Cavaliers, for example, should be screened even if they do not have symptoms. This is important to protect future generations from this awful condition.

The cause of SM is thought to be hereditary although this disease is not completely understood yet. It seems to affect certain breeds most often, which include:

• Pomeranians
• Staffordshire Bull Terriers
• Shih Tzus
• Boston Terriers
• French Bulldogs
• Yorkshire Terriers
• Maltese Terriers
• Chihuahuas
• Miniature Dachshunds
• Miniature Poodles
• Bichon Frisés
• Pugs
• Pekingese
• Miniature Pinschers
• Cavalier King Charles Spaniels
• Griffon Bruxellois
• Havaneses
• Affenpinschers

The most effective way to diagnose SM is an MRI scan of the spinal column and brain. Your dog will need to be put under general anesthesia during the procedure and will be given oxygen and fluids. The results should indicate pockets filled with spinal fluid throughout the spinal column if your dog has SM. First, your veterinarian will need to do a thorough physical examination including palpation and auscultation, vital signs, and a complete body condition score.

Also, you need to provide the veterinarian with your dog’s medical history and the most recent symptoms you have noticed. Afterward, the veterinarian will perform some blood tests such as a serum biochemical analysis and complete blood count (CBC). Urine and stool samples will be collected for microscopic analysis as well. Then, your veterinarian will do the imaging including x-rays, ultrasound, CT scans, and MRIs.

Treating SM depends on the stage of the disease and age of your dog. The most important objective is to relieve the pain that your dog is experiencing. This may include surgery or medication as well as physical therapy in some cases.

Surgery

Cervical or cranial decompression is done to remove part of the bone that is blocking the spinal column. This procedure is successful about 80% of the time. However, in some cases (25% to 50%), the syrinx causes it to become blocked again and the symptoms will return. This can be due to the scarring or the regrowth of the syrinx.

Medication

There are a few drugs that can help with pain, swelling, and reduction of spinal fluid production: Pain medications include opioids and NSAIDs, steroids to reduce swelling, and diuretics or omeprazole to reduce the production of spinal fluid.

Physical Therapy

There are several types of therapy that can help your dog, which include aqua therapy and massage therapy. Your veterinarian can teach you how to do these yourself or you can take your dog to special physical therapy classes.

Lifestyle changes

Use a body harness rather than neck collar and avoid touching your dog in areas where it hurts them. 

If your dog was treated with surgery, you will need to be very observant for a few weeks while he heals. Provide plenty of fresh water because hydration is essential. You should also keep your dog as calm as possible, placing your dog on cage rest when needed. Call your veterinarian if you have any concerns or questions.