CONDITION

Episodic Falling Syndrome

Episodic falling syndrome is an inherited condition seen almost exclusively in Cavalier King Charles Spaniels, in which episodes of muscle stiffness prevent normal movement during moments of excitement, play, or exertion. An affected dog may suddenly freeze mid-stride, fall onto their side with rigid limbs, or adopt a bunny-hopping gait, all while remaining conscious and aware. The episodes typically last seconds to minutes, then resolve completely. Owners often arrive on this page because they have witnessed a collapse or stumble that looked alarming but did not follow the pattern of a seizure — the dog's eyes stayed open, they seemed awake, and they recovered quickly once the excitement passed. The episodes tend to begin in young dogs and can vary in frequency and severity over time. This page explores what these episodes may look like in practice, the underlying genetic and neurological mechanisms, how the condition is investigated and distinguished from other causes of collapse, and the medical and management approaches that can reduce episode frequency and severity.

Why this matters now

Episodic falling syndrome typically becomes apparent in young Cavalier King Charles Spaniels, most often between three and seven months of age, though reported ages at first presentation range from about two months to four years. The condition is inherited in an autosomal recessive pattern, meaning both parents must carry the gene for a puppy to be affected. Episodes tend to be triggered by excitement, exercise, or stress, and the pattern of triggers often becomes recognisable to owners over time.

The frequency and severity of episodes can vary widely between individuals, and the pattern may shift over a dog's lifetime. Some dogs experience episodes weekly or even daily during certain periods, whilst others may have long stretches with few or no events. In many cases, episodes become less frequent or severe as the dog matures, though this is not universal. The condition does not typically shorten lifespan, and muscle function between episodes remains normal.

Signals & patterns

Early signals

Sudden stiffness during play

The dog may freeze mid-stride or mid-movement, with the legs becoming rigid and extended. This can happen during moments of excitement, such as greeting another dog or chasing a toy, and the stiffness resolves within seconds to a few minutes.

Deer-stalking or bunny-hopping gait

Some dogs adopt an unusual gait during or just before an episode, with stiff, extended rear legs that give a characteristic high-stepping or hopping appearance. Owners may notice this when the dog is particularly animated or anticipating something enjoyable.

Brief collapse without loss of awareness

The dog may lean to one side or fall over whilst remaining fully conscious, often with eyes open and responsive to surroundings. The collapse is mechanical rather than neurological, and the dog typically gets up once the stiffness passes.

Arched or hunched posture

During an episode, the spine and trunk muscles can stiffen, causing the back to arch or the body to adopt a rigid, hunched position. This postural change may be subtle or pronounced, and it resolves as the episode ends.

Later signals

Predictable triggers become apparent

Over time, owners often identify specific situations that reliably provoke episodes, such as the sight of a lead, arrival of visitors, or the start of a walk. Recognising these patterns can help in understanding the individual dog's threshold for excitement or stress.

Longer or more complex episodes

In some dogs, episodes may lengthen or involve more muscle groups as the condition continues, with stiffness affecting all four limbs and the trunk. The dog may remain down for several minutes, though consciousness and awareness are preserved throughout.

Fatigue following episodes

After a particularly prolonged or severe episode, some dogs appear tired or reluctant to continue activity for a short period. This fatigue is temporary, and normal muscle function and energy levels return once the dog has rested.

Click to read about the biological mechanisms

How this is usually investigated

The investigation of episodic falling syndrome begins with a detailed history of the episodes, including their timing, triggers, and appearance, alongside observation of the dog's breed, age, and behaviour between events. Physical examination is typically unremarkable outside of an episode, which often points towards a neurological or inherited cause. Targeted tests are then used to rule out other conditions that can cause collapse or rigidity, and genetic testing can confirm the diagnosis when the clinical picture is consistent.

Physical examination

Purpose: A thorough neurological and musculoskeletal examination helps establish that the dog appears normal between episodes and that there are no signs of pain, weakness, or other abnormalities that might suggest alternative causes of collapse.
Considerations: Findings are usually entirely normal in dogs with episodic falling syndrome, which is itself a useful piece of information. The examination cannot confirm the diagnosis, but it can help narrow the list of possibilities.

Genetic testing

Purpose: A DNA test identifies the specific microdeletion in the BCAN gene that causes episodic falling syndrome. The test can confirm the diagnosis in affected dogs and can also identify carriers, which is useful for breeding decisions.
Considerations: The test requires a cheek swab or blood sample and is highly specific for this condition. A positive result confirms the diagnosis when the clinical signs are consistent, though the test does not predict severity or frequency of episodes.

Magnetic resonance imaging (MRI)

Purpose: MRI of the brain and spinal cord is used to rule out structural abnormalities such as syringomyelia, Chiari-like malformation, or other lesions that can cause collapse or abnormal movement in Cavalier King Charles Spaniels.
Considerations: MRI findings are typically normal in episodic falling syndrome. The scan is useful when the clinical picture is unclear or when other neurological signs are present, but it requires general anaesthesia and does not confirm the diagnosis of episodic falling syndrome itself.

Chemistry panel

Purpose: Blood chemistry helps rule out metabolic causes of collapse, such as low blood glucose, electrolyte disturbances, or liver dysfunction, which can occasionally mimic episodic events.
Considerations: Results are usually normal in episodic falling syndrome. The test is more useful for excluding other conditions than for confirming this one, and it provides a baseline if medication is being considered.

Video documentation

Purpose: Recording an episode on video allows the veterinary surgeon to observe the character of the stiffness, the dog's level of awareness, and the pattern of onset and resolution, which can help distinguish episodic falling syndrome from seizures or other paroxysmal events.
Considerations: Video is often one of the most informative parts of the investigation, particularly when episodes do not occur during a consultation. It cannot replace other tests, but it can clarify the type of event being described.

Options & trade-offs

Management of episodic falling syndrome is usually tailored to the individual dog, taking into account the frequency and severity of episodes, the impact on daily life, and the owner's observations of what triggers or worsens events. Many dogs live comfortably with minimal intervention, whilst others benefit from medication or adjustments to routine. Different combinations of approaches suit different households, and the pattern of episodes often shifts over time, so what works at one stage may need revisiting later.

Environmental and activity modification

This involves identifying and, where practical, reducing exposure to triggers that tend to provoke episodes, such as intense excitement, sudden bursts of exercise, or stressful situations. Many owners find that a calm, predictable routine and gradual warm-up before activity can reduce the frequency or intensity of events. The dog's overall quality of life is supported by allowing normal activity whilst being mindful of known triggers.

Trade-offs: This approach requires careful observation and may not be practical in all situations, particularly if triggers are unavoidable or if the dog's temperament makes excitement difficult to manage. It does not prevent episodes entirely and is often used alongside other measures.

Clonazepam

Clonazepam is a benzodiazepine medication that has muscle-relaxant and anticonvulsant properties. It is used to reduce the frequency and severity of episodes in dogs whose quality of life is affected by frequent or prolonged events. The dose is adjusted to the individual, and many dogs remain on the medication long-term.

Trade-offs: Clonazepam can cause sedation, particularly when treatment begins or when the dose is adjusted, and some dogs develop tolerance over time, requiring dose increases. It does not eliminate episodes in all individuals, and withdrawal must be gradual if the medication is stopped.

Acetazolamide

Acetazolamide is a carbonic anhydrase inhibitor that is sometimes used in dogs whose episodes are frequent or poorly controlled by other means. It is thought to alter the excitability of nerve cells, though the precise mechanism in episodic falling syndrome is not fully understood. It may be used alone or in combination with other medications.

Trade-offs: Acetazolamide can cause increased thirst and urination, and it may not be suitable for dogs with certain kidney or metabolic conditions. Response is variable, and not all dogs show a clear reduction in episode frequency.

Monitoring and supportive care during episodes

For dogs with infrequent or mild episodes, many owners choose to monitor without medical intervention, ensuring the dog is safe during an event and allowing it to resolve on its own. This involves staying calm, preventing injury from falls, and giving the dog space to recover without restraint or over-handling.

Trade-offs: This approach is appropriate when episodes are brief and do not cause distress, but it may be less suitable if episodes are frequent, prolonged, or cause the dog to fall in hazardous situations. It does not reduce the frequency of events.

Common misconceptions

Misconception:

"Episodic falling syndrome is a type of seizure or epilepsy."

Reality:

Dogs with episodic falling syndrome remain fully conscious and aware during episodes, and there is no seizure activity in the brain. The muscle stiffness is caused by a genetic fault affecting the structural support of certain nerve pathways, not by the abnormal electrical discharges that characterise epilepsy. The two conditions are investigated and managed differently.

Misconception:

"Episodes will worsen progressively over time and eventually cause permanent disability."

Reality:

Episodic falling syndrome is not a progressive degenerative disease. Muscle function between episodes remains normal throughout life, and many dogs experience fewer or less severe episodes as they mature. The pattern can vary, and some dogs do continue to have frequent events, but the condition does not typically lead to permanent weakness or loss of mobility.

Misconception:

"Affected dogs should be prevented from exercising to avoid triggering episodes."

Reality:

Most dogs with episodic falling syndrome can enjoy normal activity, and exercise itself is not harmful. Episodes are triggered by excitement or exertion, but restricting all activity is rarely necessary and can affect the dog's overall wellbeing. Many owners find that gradual warm-up, avoiding sudden bursts of intense play, and recognising individual triggers allows their dog to remain active and engaged.

Related conditions

Epilepsy in Dogs

Epilepsy in dogs can sometimes be confused with episodic falling syndrome by owners, as both conditions involve sudden, recurrent episodes during which the dog's behaviour changes abruptly. The key distinction lies in consciousness: dogs with epilepsy typically lose awareness during a seizure, whilst those with episodic falling syndrome remain alert and responsive throughout the episode of muscle stiffness.

Eclampsia in Dogs

Eclampsia can cause sudden muscle rigidity and tremors that may superficially resemble the stiffness seen in episodic falling syndrome, though eclampsia occurs in a specific context (nursing females with low blood calcium) and is typically accompanied by other signs such as restlessness, panting, and altered mentation. The muscle changes in eclampsia reflect a biochemical disturbance rather than the inherited neuromuscular mechanism underlying episodic falling syndrome.

Addisons Disease in Dogs

Addison's disease in dogs can present with episodic weakness or collapse triggered by stress or exertion, which may prompt owners to consider conditions such as episodic falling syndrome. The collapse in Addison's disease tends to involve generalised weakness rather than the rigid, locked-limb stiffness characteristic of episodic falling, and metabolic testing typically reveals abnormalities in electrolytes and cortisol that are not present in episodic falling syndrome.

Fibrocartilaginous Embolism (FCE)

Fibrocartilaginous embolism can cause sudden-onset weakness or abnormal gait that might initially be mistaken for an episode of falling or stiffness, particularly if the dog is observed during activity. However, FCE typically results in persistent neurological deficits affecting one side or specific limbs that do not resolve spontaneously, in contrast to the self-limiting, reversible episodes seen in episodic falling syndrome.

Understanding the pattern of episodes in an individual dog often takes time, and what works at one stage may shift as the dog matures or as triggers become clearer. For Cavalier King Charles Spaniels, episodic falling syndrome exists alongside other inherited conditions that can affect this breed, and awareness of the broader health picture can inform conversations about management and long-term planning. The experience of living with a dog whose episodes vary unpredictably is one many owners share, and the strategies that prove most workable often emerge through observation and gradual adjustment.

Last reviewed: 1 July 2026 · Dr Alastair Greenway MRCVS