Syringomyelia in Cavalier King Charles Spaniels: A Devastating Reality for a Beloved Breed
As a dog lover, it‘s impossible not to be charmed by the gentle, playful, affectionate nature of Cavalier King Charles Spaniels. With their silky coats, expressive eyes, and boundless love for their humans, it‘s no surprise Cavaliers consistently rank in the top 20 most popular breeds in the US [1].
But behind those heart-melting moments snuggling your Cavalier on the couch, an alarming statistic looms: up to 70% of Cavaliers will develop a devastating neurological disorder called syringomyelia (SM) by the age of 6 [2]. This sobering reality is well-known to Cavalier owners, who often witness the heartbreaking decline of their lively, cuddly companion into a pain-ridden, disabled dog far too early.
At its core, syringomyelia is the result of a mismatch between brain and skull size. The vast majority of Cavaliers (up to 95% in some studies) have a congenital malformation called Chiari-like malformation (CM) [3]. With CM, the back part of the skull is too small, causing the cerebellum to be squished through the opening at the base of the skull (foramen magnum). This blocks the normal flow of cerebrospinal fluid (CSF) between the brain and spinal cord.
Over time, the abnormal CSF pressure causes fluid-filled cavities called syrinxes to develop within the spinal cord, most commonly in the neck region. These syrinxes put pressure on the surrounding nerves, causing a wide range of pain and neurological symptoms. In a breed already prone to heart disease (mitral valve disease), eye issues (cataracts and retinal dysplasia), and orthopedic problems (hip dysplasia and patellar luxation), syringomyelia is yet another devastating blow.
Syringomyelia by the numbers
Just how common is syringomyelia in Cavaliers? Far too common, research shows. Numerous studies around the world have used MRI screening to investigate the prevalence of CM and SM in the breed. And the results are staggering:
| Age | % with Syrinx | Study |
|---|---|---|
| 12 months | 25% | Parker 2011 [2] |
| 3 years | 50% | Thofner 2015 [4] |
| 5 years | 50% | Parker 2011 [2] |
| 6 years | 70% | Parker 2011 [2] |
| 7 years | 75% | Cirovic 2022 [5] |
| 9 years | 92% | Thofner 2015 [4] |
Table 1. Percent of CKCS with a syrinx visible on MRI at different ages, across multiple studies.
It‘s a devastating reality – the question is not "if" a Cavalier will develop syringomyelia, but "when". And often SM strikes young; dogs may start showing signs as early as 6 months of age, with the majority symptomatic by 4 years [2,3,4].
In a 2017 study of 189 symptomatic UK Cavaliers, the average age at onset of signs was just 3.8 years, with 50% showing signs by 3 years and 87% by 6 years [6].
Figure 1. Cumulative percent of 189 symptomatic CKCS showing clinical signs of syringomyelia by age. Adapted from Spiteri 2017 [6].
A challenging diagnosis
For Cavalier owners, one of the most difficult aspects of syringomyelia is how long it can take to get a definitive diagnosis. Symptoms often start subtly – a little scratching at the ears, an intermittent yelp when picked up. It‘s easy to brush these signs off as just a bothersome ear infection or a pulled muscle. But Cavalier owners must be vigilant, as SM is always a possibility lurking in the background.
Many owners go through months to even years of seeing their dog decline without answers. Karen, a long-time Cavalier owner in the UK, shared her experience: "Our girl Rosie first showed strange symptoms around 16 months. She would yelp when touched near her shoulder blades and went through bouts of frantic scratching. The vets treated her for allergies but the signs kept worsening. It wasn‘t until an MRI nearly 2 years later that syringomyelia was officially diagnosed. In hindsight, all those early red flags added up."
Reaching a diagnosis is often a process of ruling out other potential causes first. "With Cavaliers, we have to consider numerous differentials for neck pain and scratching. These include ear infections, skin allergies, orthopedic pain, and intervertebral disk disease (IVDD)," explains Dr. Julia Tomlinson, BVSc, MS, DACVS, CCRP, CVSMT, a board-certified veterinary surgeon and rehabilitation practitioner with a special interest in Cavalier health. A full exam, ear swab, skin tests, x-rays, and even advanced imaging like a CT scan may all be part of the work-up before an MRI is pursued.
An MRI provides the highest detail images of the soft tissues, making it the gold standard for diagnosing SM. But with limited availability, need for general anesthesia, and high cost (often $2000-3000 in the US), MRI can be a huge barrier. "It‘s an unfortunate reality that many dogs go undiagnosed or are treated with incomplete information because an MRI isn‘t technically or financially feasible," laments Dr. Tomlinson.
Even with an MRI, it‘s important to recognize that not all syrinxes cause clinical signs. Dogs may have a visible syrinx on MRI but no symptoms, known as asymptomatic or subclinical SM. In fact, in a study of 79 asymptomatic Cavaliers, 25% had a syrinx at 12 months old and 70% by 6 years [2]. While asymptomatic dogs aren‘t painful at the time, they are still at higher risk for developing clinical SM in the future. Any Cavalier with a syrinx must be monitored closely.
Living with syringomyelia: a day in the life
For the tens of thousands of Cavaliers affected by syringomyelia worldwide, daily life revolves around maximizing comfort and minimizing pain. Liz, who has cared for three SM-affected Cavaliers in the UK, describes her management approach:
"Medication is the cornerstone of keeping them comfortable. Most are on a cocktail of gabapentin, carprofen or other NSAIDs, omeprazole to protect the stomach, and sometimes tramadol for breakthrough pain. The doses and combinations change over time as their disease progresses and pain worsens. It‘s a constant balancing act.
Twice daily gabapentin seems to be the biggest help for the nerve pain. When the scratching intensifies, I know it‘s time to increase the dose. We‘ve also had success adding amantadine, which boosts the gabapentin when it starts losing effectiveness. And hydrotherapy has made a huge difference for our SM crew in keeping their core strong and taking pressure off the neck and shoulders.
Our home is SM-proofed with soft bedding, rubber mats, ramps to the sofa, and raised bowls everywhere. No jumping, no collars, and lots of interactive puzzle toys to keep their minds busy and not focused on scratching. I strictly limit visitors from touching them and have a zero tolerance policy for rough play, even if it‘s an accident. An extra treat is not worth seeing them yelp in pain later.
It‘s a 24/7 job and emotionally draining at times. With multiple affected dogs, someone is always having a painful day. But I wouldn‘t trade the time I‘ve had with each of them for anything. They are the most loving, resilient creatures."
Figure 2. Many drug and lifestyle modifications can help keep an SM-affected Cavalier comfortable. Image credit: Antonio Sanchez, Unsplash.
Breeding conundrums: the heart vs. the head
Undeniably, much of the heartache of syringomyelia could be reduced or prevented through more responsible breeding practices. CM/SM is highly heritable in Cavaliers, with multiple genes thought to be involved in this complex disease. With MRI screening, breeders can select the best possible pairings using lines with a lower incidence and later onset.
The Kennel Club (UK) and Cavalier Club (USA) have established some guidelines, recommending that all breeding dogs be MRI screened and graded at a minimum age (2.5 years). Ideally, neither parent should have CM or SM themselves, though this severely limits the breeding pool. The Kennel Club maintains a health database where breeders can access MRI grades of potential mates. There are also ongoing efforts, like the Cavalier Matters Charitable Trust, funding research to better understand the inheritance of CM/SM.
But progress is slow. Even with strict MRI screening and selection pressure, it‘s estimated to take at least 5 generations (25+ years) to substantially reduce the prevalence of SM in Cavaliers [7,8]. Many are skeptical this is achievable, feeling the breed is too far engrained to reverse course now.
Others raise ethical concerns about knowingly breeding dogs at risk for SM and the toll it takes on the offspring and their owners. Some go as far as suggesting outcrossing Cavaliers with other breeds to reduce incidence. These remain hotly debated issues with no clear consensus.
For prospective Cavalier owners, the best approach is extensive research and asking breeders tough questions. The more that puppy buyers demand proof of health testing for SM, the more pressure for breeders to comply and prioritize producing healthy dogs above all else.
It‘s a devastating reality to confront, but one that can‘t be ignored. Syringomyelia touches the lives of most Cavalier owners in some way. It‘s a relentless, progressive disease with no easy fix. But with dedicated management, affected dogs can still enjoy a good quality of life for many years. And by supporting research, raising awareness, and expecting the highest standards from breeders, there is hope the next generation of Cavaliers may be spared this heartbreaking fate.
References
- American Kennel Club. Most Popular Dog Breeds of 2021. https://www.akc.org/expert-advice/dog-breeds/most-popular-dog-breeds-of-2021/
- Parker JE, Knowler SP, Rusbridge C, et al. Prevalence of asymptomatic syringomyelia in Cavalier King Charles spaniels. Veterinary Record. 2011;168(25):667.
- Hechler AC, Moore SA. Understanding and Treating Chiari-like Malformation and Syringomyelia in Dogs. Topics in Companion Animal Medicine. 2018;33(1):1-11.
- Thofner MS, Stougaard CL, Westrup U, et al. Prevalence and Heritability of Symptomatic Syringomyelia in Cavalier King Charles Spaniels and Long-term Outcome in Symptomatic and Asymptomatic Littermates. Journal of Veterinary Internal Medicine. 2015;29(1):243-250.
- Cirovic S, Sparkes A, Johnson B, et al. Morphometric features of Chiari-like malformation in Cavalier King Charles spaniels:a retrospective case-control study. Scientific Reports. 2022;12(1):7425.
- Spiteri M, Knowler SP, Rusbridge C. Age of onset and symptom distribution in syringomyelia in 189 Cavalier King Charles Spaniels presenting to a UK referral hospital [abstract]. Journal of Veterinary Internal Medicine. 2017; 31(4):1338-1433.
- Lewis T, Rusbridge C, Knowler P, et al. Heritability of syringomyelia in Cavalier King Charles spaniels. The Veterinary Journal. 2010;183(3):345-347.
- Knowler SP, McFadyen AK, Rusbridge C. Effectiveness of breeding guidelines for reducing the prevalence of syringomyelia. Veterinary Record. 2011;169(26):681.
