CONDITION
Syringomyelia (CM/SM)
Syringomyelia describes the development of fluid-filled cavities within the spinal cord itself. These cavities form when the normal flow of cerebrospinal fluid around the brain and spinal cord is disrupted, often because the space at the back of the skull is smaller than usual. The condition is seen most often in certain breeds, particularly Cavalier King Charles Spaniels, though it can occur in others. Owners may notice signs that suggest discomfort in the head or neck — scratching at the air near the ear or shoulder without making contact with the skin, reluctance to be touched around the head, sensitivity to collar pressure, or changes in behaviour during excitement or rest. Some dogs show no outward signs at all, while others may develop difficulty walking or coordinating movement if the cavities affect larger portions of the spinal cord. The picture varies widely between individuals. This page explores what these signs may reflect, how the condition is identified through imaging, the factors that influence whether and how it progresses, and the range of approaches — both medical and surgical — that exist to manage it. The goal is to help you understand what syringomyelia can look like and what the options are, not to tell you what is happening in your own dog.
Why this matters now
Clinical signs of syringomyelia most commonly appear between 6 months and 3 years of age, though they can develop at any point in life. Some dogs with MRI-confirmed syrinxes never develop clinical signs, whilst others become symptomatic early.
The condition tends to be progressive in affected dogs, with symptoms often worsening over time. The rate of progression varies considerably between individuals. Some dogs remain stable for extended periods, whilst others experience gradual deterioration in comfort and neurological function.
Signals & patterns
Early signals
Phantom scratching
A distinctive scratching motion towards the neck, ear or shoulder without making contact with the skin. Often occurs during walks or excitement.
Sensitivity around the head, neck or shoulders
Dogs may flinch, yelp or show discomfort when touched in certain areas or when wearing collars.
Reluctance to be groomed
Affected dogs may resist brushing or show discomfort during coat care, particularly around the neck.
Sleep disruption
Dogs may wake frequently, change position often, or seem unable to settle comfortably.
Later signals
Persistent pain behaviours
Crying out unexpectedly, holding the head in unusual positions, or appearing distressed without obvious cause.
Weakness or wobbliness
Coordination problems may develop, particularly affecting the hind legs.
Facial nerve signs
Some dogs develop facial sensitivity, ear problems, or difficulty swallowing.
Severe scratching episodes
Phantom scratching may become more frequent and intense as the condition progresses.
Click to read about the biological mechanisms
How this is usually investigated
Diagnosis of syringomyelia requires advanced imaging, as clinical signs alone cannot confirm the presence of syrinxes.
MRI of brain and cervical spine
Neurological examination
CSF analysis
Screening programmes
Options & trade-offs
Management of CM/SM ranges from medical pain control to surgical intervention, depending on severity and individual circumstances.
Medical pain management
Various medications can help manage neuropathic pain, including gabapentin, pregabalin, and non-steroidal anti-inflammatory drugs.
Trade-offs: May provide good control in many dogs. Requires ongoing medication and monitoring. Effectiveness varies between individuals.
Drugs affecting CSF production
Medications like omeprazole, furosemide, or corticosteroids may reduce CSF production and improve comfort in some cases.
Trade-offs: Evidence for efficacy is variable. May be used alongside pain medications.
Surgical decompression
Surgery to enlarge the foramen magnum and restore CSF flow can be considered in severe cases.
Trade-offs: Major procedure with associated risks. Outcomes are variable and symptoms may recur. More likely to help when performed earlier in disease course.
Lifestyle modifications
Using harnesses instead of collars, avoiding excitement triggers, and managing activities may help reduce symptom frequency.
Trade-offs: Supportive measure that may improve comfort but does not address underlying pathology.
Common misconceptions
"Phantom scratching means the dog has an itch or skin problem."
Phantom scratching in CM/SM reflects neuropathic sensations caused by spinal cord damage, not a skin issue. The dog is responding to abnormal nerve signals.
"Only Cavalier King Charles Spaniels get this condition."
While Cavaliers have very high prevalence, CM/SM affects many toy and small breeds including Griffon Bruxellois, Chihuahuas, and others.
"Surgery cures the condition."
Surgery can help relieve symptoms in some cases, but outcomes are variable and symptoms may recur. The underlying skull/brain mismatch cannot be corrected.
Related conditions
Hydrocephalus
Hydrocephalus and syringomyelia both involve disrupted cerebrospinal fluid dynamics, and in some dogs—particularly small or brachycephalic breeds—both conditions can occur together when developmental changes to the skull affect fluid flow around the brain and spinal cord. The imaging used to investigate one condition often reveals the other.
Intervertebral Disc Disease (IVDD)
Intervertebral disc disease and syringomyelia can both cause neck pain, reluctance to move the head, and changes in gait, though the underlying mechanisms differ. In dogs showing spinal signs, imaging may be needed to distinguish between compression from disc material and the presence of fluid cavities within the cord itself.
Brain Tumours
Brain tumours can alter the flow or absorption of cerebrospinal fluid, occasionally leading to secondary syringomyelia when increased pressure disrupts normal fluid movement around the spinal cord. Both conditions may present with neurological signs that develop gradually and require advanced imaging to identify.
Meningioma
Meningiomas arising near the base of the skull or along the spine can obstruct cerebrospinal fluid pathways in a way that resembles the disruption seen in syringomyelia, and in rare cases the two may coexist. The distinction often rests on imaging findings rather than clinical signs alone.
Steroid-Responsive Meningitis-Arteritis (SRMA)
Steroid-responsive meningitis-arteritis causes inflammation of the membranes around the brain and spinal cord and can present with neck pain and reluctance to move the head—signs that may overlap with those seen in syringomyelia. The two conditions arise from different mechanisms, but both may require imaging and cerebrospinal fluid analysis to distinguish them.
Understanding the hereditary nature of CM/SM in affected breeds provides important context for owners. Learning to recognise characteristic signs like phantom scratching may help with early identification. Discussing harness use and collar avoidance with your veterinary team can be helpful for affected dogs. Awareness of available screening programmes may be relevant for those involved with breeding.
Last reviewed: 24 April 2026 · Dr Alastair Greenway MRCVS