Neurologic disease FAQs

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What is epilepsy?

Epilepsy is a seizure disorder featuring multiple seizures over time.  If no underlying cause can be found for the seizures the disease is called idiopathic or primary epilepsy.  Primary epilepsy is not a single disease, but several similar ones.  Research thus far indicates that no single gene or set of genes causes the disease in every breed.

 How do I know if my dog has epilepsy?

Epilepsy rarely arises in Aussies under a year of age.  Onset after seven years is also very unusual.  Any dog that suffers a major seizure should be taken to a veterinarian for evaluation and testing.  Seizures can be caused by many things–injury, a variety of diseases, toxic exposure, as well as heredity; to come to a diagnosis of primary epilepsy the vet must rule-out other possible causes.  Any of a variety of tests may be done, depending on the dog’s health history.  When all other likely causes of the seizures are ruled out, the diagnosis is epilepsy.

 What does having epilepsy mean for my dog?

Primary epilepsy cannot be cured and will not go away.  The dog will seize if untreated.  Seizures may occur periodically for the life of the dog even with treatment.  They often get worse if not controlled by medication.  The drugs themselves may have serious side effects and in some cases they become ineffective.  Epilepsy can kill.

 How common is epilepsy in Aussies?

Approximately 4% of Aussies have epilepsy.

 Is epilepsy inherited?

Yes.  The mode of inheritance for epilepsy is complex.

 Is there a DNA test for epilepsy in Aussies?

Not at this time.

 What does epilepsy mean for my breeding program?

This is a serious, incurable, sometimes difficult to treat disease.  Affected individuals should not be bred.  Because of the severe quality of life impacts of this disease and the long-term emotional and financial burden care for an epileptic dog can place on owners, first-step relatives (parents, offspring, and full or half siblings) of an epileptic dog should not be bred.  Other near relatives might be bred but only to mates without any recent family history of epilepsy.  Recent, in this case, means within three steps of relationship in any direction.

 What is neuronal ceroid lipofuscinosis (NCL)?

NCL, sometimes called canine ceroid lipofuscinosis in dogs, is a storage disease; toxins that the body normally would eliminate as waste build up in certain tissues.  With NCL it happens in the nervous system.  Affected dogs start showing signs around a year and a half of age.  They have seizures, but may also lose their eyesight, exhibit circling behavior, dementia and aggression. The disease kills the dog by the time it is 2-3 years old.  NCL is inherited in some breeds.  It is extremely rare in Aussies.

 How is NCL diagnosed?

Diagnosis of CCL can be difficult.  The only totally definitive test is through examination of nervous system tissue upon necropsy.  Levels of cartinene in the blood may be reduced, but this alone is not conclusive.

Is NCL a form of epilepsy?

No.  Epilepsy is a much more common disease in Aussies.  It usually comes on at about the same age as NCL and is sometimes lethal.  However, the other signs of NCL should enable the treating veterinarian to recognize that NCL seizures are due to something other than primary epilepsy.

Is NCL hereditary?

Yes, however there are multiple forms of the disease caused by different genes.  There are DNA tests for some forms.

Can a DNA test be used to diagnose a dog with NCL before it dies?

Maybe, if you know which form of NCL the dog might have.  Certain forms are highly associated with certain breeds.  There is a test that is offered for Aussies but only one Aussie has been found with that particular mutation.  If an Aussie may have NCL, that would be the test to run first, but if the results say it is clear the dog may still have a different form of NCL.

Are muscle tremors in Aussies a sign of disease?

It would depend on the situation.  If the dog is fatigued, it may simply be a sign of overworked muscles.  If there are other signs of something wrong, like a suddenly abnormal gait, exercise intolerance, or a tendency to collapse there may be something else wrong.  In a situation like that the dog should be taken to a vet for evaluation.  (Try to take a video of what’s going on because it may not be happening by the time you get to the vet’s office.)  However, some Aussies have muscle tremors alone.  The tremors may be a sign of a largely benign condition called hypomyelinogenesis.  Some owners report it only happens when the dog is excited or stressed.

My dog is very intense, is this why he has tremors?

Possibly, if it only happens when she is closely focused on some object or activity.

Do muscle tremors mean my dog has epilepsy?

In most cases, no.  A dog having a seizure would almost certainly be having other signs indicating that a seizure was in progress.  With epilepsy, nerves in the brain fail to turn off the current when they should.  The open switch causes a chain reaction, overloading one neuron after another.  If only a small area of the brain is affected, you get a focal seizure, a minor event that might include muscle tremors.  If it affects a large area you get major seizures that will cause far more that muscle tremors.  Epileptic seizures are centered in the brain.  The misfiring motor nerves that cause the leg tremors are localized and do not affect the brain.  If a dog had both epilepsy and tremors when not seizing it would be coincidence.

What is hypomyelinogenesis?

Myelin is the “insulation” on nerves.  In hypomyelinogenesis, this insulation failed to develop properly.  The most frequent sign of the disease is muscle tremors though in some species there may be seizures.  Clumsiness when walking and head tremors may be seen in young puppies but typically go away.  In these cases the myelin development may only have been delayed and the signs go away as the myelin develops.  However, muscle tremors may persist in adult dogs.  Seizures are reported in some species, likely when the lack of myelinization is in the brain.  This doesn’t spear to be the case in dogs.  Rat Terriers have a form that includes hypothyroidism and goiter. 

What causes hypomyelinogenesis?

Information on this disease in dogs is limited.  Causes of the disease across species include infection, dietary imbalance, and heredity.

What does having hypomyelinogenesis mean for my dog?

If the muscle tremor frequently seen in Aussies is hypomyelinogenesis, the impact on the dog is very minor.  The tremors come and go and do not appear to be associated with any of the other symptoms reported with this disease.

 How common is hypomyelinogenesis?

If the typical Aussie muscle tremor is hypomyelinogenesis, very common.

 Is hypomyelinogenesis hereditary?

It is in several breeds, none of them collie-type.  In those breeds it is X-linked so it would be seen more frequently in males than females.  There is no information indicating this is the case in Aussies, but it has been reported in related dogs so heredity is a possibility.

What does hypomyelinogenesis mean to my breeding program?

The effects of the muscle tremors, whether or not they are a form of myelinogenesis, are so minor it isn’t cause to withhold a dog from breeding.  However, it is unsightly and call it a fault is justified.  If you don’t like it, don’t breed dogs that have it to each other and avoid normal mates who have numerous affected family members.

What is exercise-induced collapse (EIC)?

EIC is a neurologic disorder in which strenuous exercise may trigger a collapse episode.  One form of EIC has been identified in the Labrador and several other breeds.  The type seen in Australian Shepherds is different; because it is most frequently observed in Border Collies it is often called “Border Collie Collapse.”  Several collie-type breeds are affected.  Other descriptions of the disease are exercise-induced hyperthermia, stress seizures, and “the wobbles.”

How do I know if my dog has EIC?

Dogs with the Border Collie form of EIC will become disoriented, confused, sway, stagger, or even fall to the ground after a few minutes of vigorous exercise.  During an episode a dog will make exaggerated vertical movement of its legs while walking.  If turning its legs may cross over each other.  It may also scruff its feet along the ground.  Hot temperatures, elevated excitement, and intensity of exercise may all contribute to triggering episodes.  A few won’t show signs until a few minutes after exercising.  Episodes may last from a few minutes to a half-hour, after which the dog returns to normal.

How is EIC diagnosed?

Patient history and observation of behavior during an episode are the only way to diagnose EIC in collie type breeds at present.  Episodes virtually never happen in a vet’s office, so if your dog has one try to take a video so the vet can see what happens.

What does having EIC mean for my dog?

Activity will need to be limited.  If the dog has been active in competitive physical events, it should be retired.

How common is EIC in Aussies?

Unknown at this time.  It is seen mostly in dogs engaged in vigorous activities like agility or stockwork.

Is EIC inherited?

Probably, given this form’s presence in several collie-type breeds.

 What does EIC mean for my breeding program?

Affected dogs should probably be withdrawn from breeding and certainly should not be bred tight on their own pedigrees or to dogs with affected relatives.

 What are hypoglycemic seizures? 

When blood sugar drops too low a seizure will sometimes result.  In dogs this is seen most frequently in young puppies that are otherwise healthy.  It is the most frequent cause of seizures in puppies in breeds where very early onset epilepsy is not reported.  (This would include the Aussie.)  A young puppy’s reserves of blood sugar are limited; if it is tired or stressed and hasn’t eaten recently a hypoglycemic seizure might be the result.  Give the puppy a little honey or something else sweet and it should recover quickly.  If it does not, a trip to the vet is in order.

 Can adult dogs have them when engaged in vigorous exercise?

It’s not impossible that an adult dog in a physically active situation might have seizures due to hypoglycemia.  In an older dog, if the seizure has clearly been tied to a hypoglycemic episode you should ask your veterinarian why the dog’s metabolism set it up for this.  It might be as simple as when/what you are feeding but it could be more serious than that.  If you’ve got a dog that is so work focused it may not eat or drink, you need to monitor that and make sure it takes breaks occasionally and that it gets some food and water.

Are hypoglycemic seizures hereditary?

Unknown.  To be on the safe side, if you breed an animal that exhibits this on more than one occasion it might be a good idea to choose a mate that does not.

What is cauda equina syndrome?   

Cauda equina syndrome is also known as degenerative lumbosacral stenosis.  The cauda equina are the nerve roots leaving the spine.  The phrase is Latin for “horse tail” and refers to the appearance of these nerves.  It can be caused by Tumors, arthritis, infection or a ruptured disc.  It is most commonly seen in large, middle aged or older, physically active dogs. Gait abnormalities, lameness and pain are a typical signs.  It can progress to the point the dog has difficulty getting to its feet or jumping.  Dogs may chew at the root of the tail or hind feet.  In the worst cases paralysis can result.

Is it common in Aussies?

No, probably because most Aussies are not large compared to dogs in general.

Is it inherited?

No.  It is a wear-and-tear issue.

What is lumbosacral stenosis?

Lumbosacral stenosis is a painful narrowing of the spinal column that can be congenital or degenerative.  It can be treated successfully with surgery.

Is it common in Aussies?

No.

Is it inherited?

In most cases skeletal degenerative disease is due to wear and tear though the conditions that lead to the wear and tear may be inherited, as with hip dysplasia.  If the cause was congenital (present at birth) there is a possibility it might be inherited, especially if it has been seen in more than one family member.  It would probably be best not to breed dogs with the congenital form of the disease.