A Condition Unique to a Beloved Breed
Syringomyelia is a condition that carries disproportionate significance in the world of Cavalier King Charles Spaniels. While it is found in other small breeds including Brussels Griffons, Affenpinschers, and Chihuahuas, it is in the Cavalier that the condition has received the most scrutiny — and with good reason. Studies suggest that a significant proportion of Cavaliers over the age of one year have the underlying structural abnormality associated with the disease, making it one of the most pressing breed health concerns in the UK today.
Understanding the Anatomy
Syringomyelia cannot be properly understood without first grasping the anatomical problem that underlies it. Most Cavaliers affected by syringomyelia have a condition called Chiari-like malformation (CLM), in which the back of the skull (the occipital bone) is too small for the cerebellum — the part of the brain it is meant to contain. This overcrowding causes the cerebellum to be partially pushed into or through the foramen magnum (the opening at the base of the skull through which the brainstem passes).
This obstruction disrupts the normal flow of cerebrospinal fluid (CSF) between the brain and spinal canal. The resulting pressure and flow abnormalities lead, in some affected dogs, to the formation of fluid-filled cavities within the spinal cord itself. These cavities are the syrinxes (singular: syrinx) that give the condition its name. The syrinx damages spinal cord tissue from within, causing pain and a characteristic pattern of neurological signs.
The Defining Sign: Phantom Scratching
One of the most recognisable and distressing signs of syringomyelia is phantom scratching — a behaviour where the dog scratches at the side of its neck, shoulder, or ear, usually whilst walking, without making actual contact with the skin. This scratching-in-the-air is thought to reflect abnormal sensory signals arising from the affected spinal cord, creating a sensation of itching or discomfort that the dog is attempting to relieve.
Owners sometimes initially attribute this to an ear problem, skin condition, or simple habit, and misdiagnosis is common in the early stages. The key distinguishing feature is that the scratching typically occurs on the move and does not result in physical contact with the skin — unlike genuine itching, which produces visible skin changes over time.
Other Symptoms and Their Significance
Syringomyelia presents differently across affected individuals, and the range of signs can be broad.
- Neck and head pain: Yelping or vocalising without an obvious cause, reluctance to have the head or neck touched, and hypersensitivity around the collar region are common early signs.
- Scoliosis: Curvature of the spine may develop in some dogs, particularly those affected at a younger age.
- Weakness and ataxia: As the syrinx expands, weakness of the limbs and unsteady gait may develop.
- Sleep disturbance: Pain may disrupt normal sleep patterns, with some dogs refusing to lie in certain positions or waking frequently during the night.
- Sensitivity to touch or change in sensation: Some dogs show extreme sensitivity to being touched around the head, ears, or shoulders even when not actively scratching.
It is important to note that not all dogs with Chiari-like malformation develop a syrinx, and not all dogs with a syrinx are symptomatic. The severity of symptoms does not always correlate neatly with the size of the syrinx on MRI, a fact that can complicate treatment decisions.
Diagnosis
MRI is the only way to definitively diagnose syringomyelia and Chiari-like malformation. The imaging reveals the extent of the cerebellar crowding, whether the cerebellum is herniating through the foramen magnum, and the presence, size, and location of any syrinxes within the spinal cord. CT scanning is less informative for soft tissue detail but may identify bony abnormalities.
A neurological examination assessing reflexes, limb strength, and sensation, alongside a thorough history of symptoms, helps guide when MRI is appropriate and how to interpret findings in context.
Medical Management
For many dogs, particularly those with mild to moderate symptoms, medical management is the first line of treatment and can provide good quality of life for a significant period.
Medications Commonly Used
Gabapentin is widely used for its effects on neuropathic pain — the type of pain generated by damaged nervous tissue — and is frequently a cornerstone of medical management in symptomatic dogs. Pregabalin is an alternative with a similar mechanism. Non-steroidal anti-inflammatory drugs may provide additional pain relief. Omeprazole (a proton pump inhibitor) has been used based on the theory that it may reduce CSF production, though evidence for this specific use is limited. Corticosteroids such as prednisolone are sometimes used but carry significant long-term side effects.
Surgical Options
Surgery is considered for dogs whose symptoms are poorly controlled with medication, for those with rapidly progressive signs, and in younger dogs where the aim is to slow disease progression. The most common surgical procedure is foramen magnum decompression, which involves enlarging the opening at the base of the skull to reduce the obstruction to CSF flow. Some surgeons also place a patch to reconstruct the area.
Surgery does not cure the condition and does not remove the syrinx, but it can stabilise or improve symptoms in a meaningful proportion of dogs. Recurrence of symptoms is documented in some cases, and repeated surgery may be required.
Breeding and Prevention
Given the hereditary nature of Chiari-like malformation and syringomyelia, the Kennel Club and health organisations have developed breeding protocols aimed at reducing the prevalence of these conditions over generations. MRI screening of breeding dogs, ideally at a minimum age of two and a half years, is recommended. Breeding dogs with significant malformation or syrinxes is actively discouraged.
Progress has been slow, partly because the underlying genetics are complex and not yet fully understood, and partly because selection for the characteristic domed skull of the Cavalier has historically run counter to the skull size needed to comfortably house the cerebellum. Breed health and breed type are in genuine tension here, and that tension is not yet resolved.
Living with a Cavalier with Syringomyelia
Many Cavaliers with syringomyelia live comfortable, enjoyable lives with appropriate management. Avoiding collar pressure by using a harness, maintaining a healthy weight to reduce physical strain, and working closely with a veterinary neurologist to adjust medication as needed are the practical cornerstones of ongoing care. Regular follow-up MRI may be recommended to monitor syrinx progression in dogs managed medically.