Ataxia in dogs – causes of wobbling and loss of coordination

Overview

Loss of coordination is a finding whose cause needs investigation

In ataxia, control of movement is disrupted rather than the problem being simply a lack of muscle strength or lameness. A dog can nevertheless have both ataxia and weakness, particularly when pathways carrying information about body position are damaged. Paresis means a partial reduction in the ability to move. In paralysis, voluntary movement is completely absent. Impaired coordination is usually divided into 3 main forms: proprioceptive, cerebellar and vestibular ataxia.

Proprioception is information carried by the nervous system about the position of the limbs and body. The cerebellum helps fine-tune movement. A vestibular, or balance system, disorder may be located in the inner ear or brainstem. Investigations of outwardly similar wobbling therefore seek to locate the problem within the nervous system.

Causes

Disruption of information about body position

Proprioceptive ataxia can arise from damage to a peripheral nerve, the spinal cord or a nerve pathway travelling to the brain. Affected dogs may sway when walking and place their feet further apart than usual. A slipped disc, tumour, inflammation or accident can damage the spinal cord, for example. A disturbance of spinal cord blood flow, such as fibrocartilaginous embolism, can also cause signs.

Disease of the balance organs or brainstem

Inner or middle ear infection can be associated with vestibular wobbling. Other possible causes include a head injury, a tumour or medication that damages the inner ear. In sudden idiopathic vestibular syndrome in an older dog, the exact cause may remain unknown. Brainstem inflammation or infection can cause a central vestibular disorder.

Cerebellar disease and other disturbances in the body

Cerebellar atrophy, a developmental disorder, a tumour or inflammation can alter the precision of steps. Hereditary cerebellar ataxia in the Finnish Hound is associated with a change in the SEL1L gene. It is progressive cerebellar degeneration starting in puppyhood.

Low blood glucose, potassium or calcium can also be associated with wobbling. Metronidazole can cause vestibular or cerebellar signs as an adverse drug effect or through toxicity. Severe circulatory or respiratory diseases can also present as abnormal coordination.

Risk factors

Risk factors for ataxia vary according to the disease disrupting nervous system function. Congenital and developmental neurological diseases are more prominent in young animals, while tumours and degenerative diseases are more common in older ones. Idiopathic vestibular syndrome occurs particularly in elderly dogs. Disc disease can, however, cause signs in a young adult dog.

A distinct recessively inherited cerebellar ataxia is recognised in the Finnish Hound. In a study, affected puppies first showed signs at an average age of 9 weeks, ranging from 4–12 weeks. Both male and female puppies were affected. This age distribution concerns that particular hereditary disease, rather than all wobbly puppies. Among 241 dogs without signs in a genetic study of the breed, 24, or around 10%, were carriers. This is a result from an older study group, rather than a current estimate of carrier frequency in all Finnish Hounds.

Typical symptoms

The most common observation is an unsteady gait in which a dog cannot control their steps normally. Signs may include:

• Body swaying and a wider stance than usual.
• Dragging the paws so that the claws scrape against the ground.
• Steps that are too high or reach too far.
• Leaning, falling or rolling to one side.
• A head tilt and involuntary jerking eye movements, called nystagmus.
• Head tremor when starting to move or making a purposeful movement.

A dog with cerebellar signs may look almost normal at rest, although starting to move reveals a clear abnormality. With a head tilt, one ear is lower than the other. With a head turn alone, the ears remain level while the muzzle points to the side. Persistent head turning and circling in the same direction can also be associated with a forebrain lesion. A balance disorder may cause nausea, vomiting and reduced appetite. With a bilateral vestibular disorder, a dog may walk low to the ground and swing their head from side to side.

Complications and consequences

The cause determines the outlook

Some diseases causing ataxia are treatable, while others progress despite treatment. The Finnish Hound's rapidly progressive hereditary cerebellar degeneration should not be equated with a temporary balance disorder. All 10 affected Finnish Hound puppies in the study were euthanised because of rapidly progressive signs and a poor prognosis.

Severe disc-related spinal cord injury may also cause difficulty emptying the bladder.

Recovery from vestibular signs

In idiopathic vestibular syndrome in older dogs, clear improvement often begins within 2–3 days. Full recovery may occur within 1–2 weeks. Another estimate for recovery is around 2–3 weeks. Some dogs retain a permanent head tilt or mild unsteadiness. Worsening signs or a failure to start improving may indicate a more serious underlying disease.

Diagnosis at the vet

Onset of signs and neurological examination

Your vet establishes when signs began and whether they are constant, episodic or gradually worsening. Medication, possible toxin exposure and a preceding accident also form part of the history. Walking is observed from the side, front and rear on a surface with good grip. Mild loss of coordination may be particularly apparent during turns, even if walking straight is easier.

The examination distinguishes impaired coordination from muscle weakness, lameness and abnormal involuntary movements. Testing postural reactions helps locate deficits in nerve pathways and distinguish a neurological problem from an orthopaedic one. Withdrawal of a limb after touch or a pinch may be a spinal reflex. It does not by itself show that the dog consciously feels the stimulus. In cerebellar disease, proprioception tests may be normal despite clearly inaccurate step length. For example, your vet may assess whether your dog normally corrects a paw placed in the wrong position. Such tests are not forced on an injured dog unable to walk whose spine may be unstable.

Blood tests and further investigations

Blood tests can investigate whether low glucose, potassium or calcium contributes to the signs. Investigating vestibular signs may involve examining the ears, measuring blood pressure and taking blood samples. MRI can show structural changes in the brain or spinal cord. Some situations require cerebrospinal fluid analysis or targeted infection tests.

The Finnish Hound SEL1L genetic test identifies the gene change associated with that particular hereditary disease. It does not replace a neurological examination when another disease could be causing the wobbling. In the study, routine blood tests and cerebrospinal fluid cell counts in the hereditarily affected hound puppies were largely normal. MRI showed a reduced cerebellar size in 9 of the 10 affected hound puppies. A normal routine blood sample therefore does not rule out every neurological disease.

Treatment

Treatment is chosen according to the underlying cause

There is no single treatment suitable for all ataxia: the plan depends on its cause. Milder cases of disc-related spinal cord injury may be treated with rest and pain relief prescribed by your vet. More severe spinal cord compression may require surgery.

An infection of the middle or inner ear may be treated with antimicrobial medication directed at the cause. Medication may be prescribed to ease vomiting and feelings of dizziness or nausea. Corticosteroids are not generally recommended as routine treatment for idiopathic vestibular syndrome. Treatment choices belong to your vet, who also considers whether medication may have contributed to the loss of coordination.

Hospital care and safe movement

A dog with severe vestibular signs may need intravenous fluids and hospital care until they can eat and move around. In milder cases, home care may be sufficient after veterinary examination. Your dog may need help getting up, going outside, eating and staying clean.

Access to stairs is prevented in a wobbly dog to reduce falls and other injuries. A floor with good grip or a flat non-slip mat helps a dog with vestibular signs stand and walk. A dog with a balance disorder can be supported under the abdomen with a towel or support harness. With disc-related spinal cord injury, however, activity restriction and rehabilitation are tailored to the diagnosis.

Follow-up and quality of life

Agreed reassessments help establish whether recovery is progressing as expected or treatment needs to change. Worsening vestibular signs or a lack of improvement may lead to more extensive investigations. In a progressive incurable disease, assessment considers the dog's wellbeing and suffering, rather than just how walking looks.

Prevention

Genetic tests help guide breeding combinations to prevent hereditary cerebellar ataxia. In Finnish Hounds, 2 carriers of the particular gene change are not mated together, to avoid producing puppies affected by that disease. This prevention concerns the known genetic form, rather than every possible coordination disorder.

Keeping a dog with disc disease at a healthy weight and reducing jumping can lessen strain on the back. Ramps are used where necessary so that the dog does not have to jump up high. The exact cause of idiopathic vestibular syndrome in older dogs is unknown, so no single exposure that can be removed has been identified. Follow medication prescriptions and report new movement problems to the treating vet.

Important for dog owners

Record whether signs started suddenly or gradually, whether all legs are affected and whether your dog can stand. Also describe any periods without signs, head tilt, vomiting and pain. A short video recorded safely can help show what walking looks like at home. The examination adds to home observations by locating the disturbance within the nervous system.

Bring a list of all medicines and possible chemical exposures. If an injury is suspected, move your dog onto a firm surface and minimise movement of the head, neck and back. Do not test paw pain sensation by squeezing or force your dog to walk on stairs.

At home, eating, drinking, going outside and staying clean may require assistance. Agree practical care instructions according to the diagnosis and monitor which activities require more help than before. Rapid deterioration or inability to remain standing requires an emergency assessment.

Frequently asked questions

Is ataxia the same as paralysis?

No. Ataxia means impaired coordination of movement, whereas paralysis means a complete loss of the ability to move. A dog may nevertheless be both uncoordinated and weak at the same time. Your vet assesses walking, postural reactions and other neurological findings to distinguish these situations.

Can ataxia go away on its own?

Some idiopathic vestibular signs improve quickly, but this outlook does not apply to every cause of ataxia. Some diseases are progressive and incurable. Sudden wobbling is therefore investigated, particularly if your dog cannot stand or their general condition deteriorates.

Does wobbling in an older dog mean a brain tumour?

Not necessarily. An older dog can also have idiopathic vestibular syndrome, in which the exact cause is not found. A tumour is nevertheless one possible cause of a balance disorder. The course of signs, a neurological examination and imaging where necessary help identify the cause of this particular dog's wobbling.

Can a dog carry an ataxia gene without being ill?

Hereditary cerebellar ataxia in the Finnish Hound is recessively inherited, and genetic testing can distinguish carriers of the disease-associated change from dogs normal for that gene. A carrier may have no clinical signs. Mating carriers together is avoided to prevent affected puppies being born. The result concerns this particular hereditary disease, so other possible causes in a dog with signs are also investigated.

Should a wobbly dog practise walking on stairs?

Access to stairs is prevented initially because an unsteady dog may fall and be injured. A flat surface with good grip and body support where needed make everyday life easier for a dog with a balance disorder. Rehabilitation is tailored to the disease diagnosed by your vet, because disc-related spinal cord injury also requires activity restriction.