CONDITION

Syringomyelia (CM/SM)

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

Purpose: MRI is the only way to visualise syrinxes within the spinal cord and assess the degree of Chiari-like malformation.
Considerations: Requires general anaesthesia. Provides definitive diagnosis and helps guide treatment decisions.

Neurological examination

Purpose: Assesses the extent of neurological deficits and pain responses.
Considerations: Helps characterise severity but cannot confirm diagnosis without imaging.

CSF analysis

Purpose: May be performed during MRI to rule out inflammatory conditions.
Considerations: Often normal in CM/SM but helps exclude other causes of similar signs.

Screening programmes

Purpose: MRI screening is available for breeding dogs in some breeds to identify affected individuals.
Considerations: Useful for breeding decisions but findings in young dogs may not predict lifetime severity.

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 or cimetidine 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

Misconception:

"Phantom scratching means the dog has an itch or skin problem."

Reality:

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.

Misconception:

"Only Cavalier King Charles Spaniels get this condition."

Reality:

While Cavaliers have very high prevalence, CM/SM affects many toy and small breeds including Griffon Bruxellois, Chihuahuas, and others.

Misconception:

"Surgery cures the condition."

Reality:

Surgery can help relieve symptoms in some cases, but outcomes are variable and symptoms may recur. The underlying skull/brain mismatch cannot be corrected.

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