Epilepsy

Epilepsy in the Giant Schnauzer

Info

What is Epilepsy?

Epilepsy is the most common long-term neurological disorder experienced by dogs and is described as at least two unprovoked seizures occurring more than 24 hours apart. A seizure is the result of abnormal electrical activity in the brain which can lead to sudden but short-term disturbances in behavior, conscious level, and/or physical movements. Seizures may be focal, affecting only one part of the brain, or generalised, and as such presentation may vary. The frequency of seizures can also vary, ranging from an initial onset with no further episodes to regular seizures occurring most often on a monthly or 3 monthly basis. However seizure frequency has also been reported outside of these parameters.

What Causes Epilepsy/Seizures?

Often the cause of seizure activity is unknown or may be genetic. However, there are numerous other possible underlying diseases and causes for seizures that a veterinary examination may be able to either confirm or rule out.

  • Ingesting poisonous substances
  • Liver disease
  • Low or high blood sugar
  • Kidney disease
  • Vaccination reaction
  • Adverse reaction to flea treatment/medication
  • Adverse reaction to worming medication
  • Electrolyte imbalance
  • Anaemia
  • Head injury
  • Encephalitis – inflammation of the brain
  • Meningitis
  • Hydrocephalus
  • Strokes
  • Brain abnormalities e.g Brain tumour, vascular obstructions/bleeding, infection, trauma, congenital or degenerative brain disease
  • Hypothyroidism
  • Low or high blood Calcium levels
  • Hyperthermia – over exposure to heat
  • Vitamin deficiencies / malabsorption e.g. thiamine (B1), cobolamin (B12), taurine
  • Dehydration
  • Internal parasites – lungworm can live in the heart, lungs and sometimes the brain
  • Cancers

There are also many episodes that can mimic seizures (e.g. syncope (fainting), cervical muscle spasm). Therefore, it is important to obtain a thorough veterinary examination.

Poisonous substances include:

  • Ingestion of medications – e.g. Ibuprofen, antidepressants, decongestants
  • Rodent poisons – affected animals can show symptoms anywhere from two days to several weeks after exposure
  • Heavy Metals – e.g. lead (which may be in paint), linoleum, batteries
  • Poisonous plants – e.g. Azaleas, rhododendrons, Tulip and daffodil bulbs, Eucalyptus, Sago palms; eating just a few seeds may be enough to cause vomiting, seizures, and liver failure
  • Household chemicals – e.g. disinfectants, paint thinner, window cleaner, toilet cleaners, air fresheners, scented oils/candles, scented diffusers, essential oil burners, fly killer, aerosols, cleaning products
  • Garden chemicals – e.g. snail/slug poison, weed killer, fertilizers, insecticides, pool chemicals
  • Antifreeze
  • Foods – e.g. Chocolate, raisins/grapes, foods containing xylitol sweetener, alcohol, macadamia nuts, rosemary

 

Seizure Triggers

Owners are often able to predict when their dog may have a seizure by identifying a change in behaviour and monitoring the frequency of seizures along with the dog’s activity. Reported behavioural changes included, anxiety, hyperactivity, clinginess, hiding and vomiting. Although seizures have been noted at all different times of the day, the most likely time for a seizure to occur appears to be after midnight into the early hours of the morning up to 9am whilst the dog is sleeping or resting. Potential triggers noted by owners include:

  • Stress
  • Diet
  • Puberty/hormones
  • Flea treatment
  • Worming medication
  • Weather
  • Vaccinations
  • Loud noises

Prevalence

The UK Schnauzer Breed Clubs 2013/2014 Joint Schnauzer Breeds Health Survey reported a prevalence of 4% (11) out of 275 live Giant Schnauzers. And the UK Kennel Club’s Health Survey 2014 found the prevalence to be 3.7% (3/82 live dogs).

Table 1

From information obtained via the Giant Schnauzer seizure/epilepsy study it was possible to identify the number of new cases per year compared to the number of UK puppy registrations, in order to determine the incidence of epilepsy. Those born and registered in the UK over the previous 10 years; 2009-2018 (19) dogs, were compared against UK KC puppy registrations for the same period (2,194), indicating an incidence of 1 in 100 (0.9%) (see Table 1).

Therefore, whilst 3.7 – 4% of the population may be living with epilepsy the seizure study showed that the chances of a puppy being affected was 1 in 100 (0.9%)

In addition, males in the study were 1.9 times more likely to be affected than females.

Age of Onset

The breed specific seizure study showed that the most common age of onset in females is between 6 months and 2 years, and between 1 and 3 years in males. Although seizure onset has also occurred above this age in both males and females, the risk appeared to be reduced further after the age of 6 years.

Mode of Inheritance

It is currently not possible to determine the mode of inheritance for those that may have a genetic link, however it is thought to be inherited in a complex manner, affected by many genes and may also involve an environmental element/non-genetic risk factor in some cases.

Signs & Symptoms

Focal Seizures

Focal seizures occur in only one part of the brain and affect the corresponding area of the body. Presentation can vary depending on which lobe of the brain is affected, typical motor signs include facial twitching, muscle twitching of one extremity, rhythmic blinking or head shaking. Autonomic nervous system signs can cause excessive salivation, vomiting and dilated pupils. And behavioural signs include restlessness, anxiety, attention seeking, and fear behaviour. In some cases a seizure may begin as a focal seizure and quickly progress to a generalised seizure.

Generalised Seizures

Generalised seizures usually involve loss of consciousness often seen with jerking or shaking movements and muscle twitching. Both sides of the brain and body are affected, and muscles may stiffen causing rigid limbs, or rapid and rhythmic jerking. There may be a sequence of stiffness and jerking or sporadic jerks on both sides of the body. There may also be loss of control of the bladder and/or bowel. Seizures can also appear as a sudden drop attack with no twitching or jerking. The seizure comes on suddenly, lasting only a short period of time (a few seconds or a few minutes), and is followed by a post-ictal (after seizure) state. The post-ictal phase may involve transient confusion, excessive salivation, panting, apparent loss of vision, and/or restlessness. This period may last anything from a few minutes to an hour, or may be extended in some cases.

A cluster is defined as two or more seizures within a 24-hour period, with a recovery of consciousness. Status epilepticus is a seizure lasting longer than 5 minutes or two or more seizures without a recovery of consciousness, requiring urgent veterinary attention.

Diagnosis

There is currently no specific diagnostic or DNA test available to determine whether a dog is affected, and the diagnosis is one of exclusion, where veterinary tests are performed in order to rule out any underlying cause. The vet will take a comprehensive medical history along with a neurological examination, and may perform a number of different diagnostic tests such as bloods, urinalysis, MRI scan of the brain and cerebrospinal fluid analysis. If all tests are found to be normal, and no cause can be identified a diagnosis of Idiopathic Epilepsy is made, which simply means Epilepsy of unknown cause. Idiopathic epilepsy is often thought to have a possible genetic link.

Treatment

Treatment will depend on the presence of any underlying disease or cause. If a cause can be found, treatment will focus on correcting or stabilising the underlying issue where possible, and eliminating/minimising any seizure triggers. Idiopathic Epilepsy is most often treated with Anti-epileptic drugs (AEDs) either a single medication therapy or a combination of more than one drug, depending on the frequency of seizures. Dietary changes may also be beneficial, and some owners have found herbal calming remedies to have a beneficial effect. Different treatment regimes have proved to have varying degrees of success and appear to be individual to each particular dog

Prognosis

The prognosis depends on any underlying causes, and also the severity of seizures along with responsiveness to treatment. For Idiopathic Epilepsy the majority of dogs often live a normal life between seizures. A study carried out among Giant Schnauzers having seizures showed that 55% required treatment, mainly with prescription medication, and 5% of these with herbal remedies. The remainder received no treatment at all in cases where seizures were less frequent. 50% of those treated saw some improvement, however where seizures were poorly controlled 28% died as a direct result, most often between 3-4yrs of age. There is no cure for Idiopathic Epilepsy however the aim is to manage and monitor seizures whilst maintaining a good quality of life. 

Owner Advice

Owner Advice

During a Seizure

Stay calm.

Remove any obstacles/items that may cause injury to the dog, and keep hands away from the dogs mouth to avoid getting bit.

Monitor the situation, timing the duration of a seizure is helpful to ensure the correct management. Contact your vet if a seizure is prolonged more than 5 minutes, also with cluster seizures were a number of fits occur without 24 hours.

Keep Track of Seizures

The Royal Veterinary College (RVC) developed an epilepsy tracker app to provide information and facilitate monitoring of seizure activity. The app is free to download from the RVC website

Keep a seizure diary of exactly what happens, when, where, and anything that is common with each seizure. Observe for anything that may trigger a seizure, previously reported triggers include:

  • Stress
  • Diet
  • Puberty/hormones
  • Flea treatment
  • Worming medication
  • Weather
  • Vaccinations
  • Loud noises

 

Identify or Rule Out Any Underlying Cause

If your dog has just started having seizures consult with a vet, where more than one seizure has occurred your vet may want to do more tests to find out if there is an underlying illness or cause. Veterinary investigations may include; blood tests, urine test and later an MRI scan of the brain and cerebro-spinal fluid analysis.

Rule out any contact with poisonous substances or medications where reactions are known to cause seizures. Different poisons can include:

  • Ingestion of medications – e.g. Ibuprofen, antidepressants, decongestants
  • Rodent poisons – affected animals can show symptoms anywhere from two days to several weeks after exposure
  • Heavy Metals – e.g. lead (which may be in paint), linoleum, batteries
  • Poisonous plants – e.g. Azaleas, rhododendrons, Tulip and daffodil bulbs, Eucalyptus, Sago palms; eating just a few seeds may be enough to cause vomiting, seizures, and liver failure
  • Household chemicals – e.g. disinfectants, paint thinner, window cleaner, toilet cleaners, air fresheners, scented oils/candles, scented diffusers, essential oil burners, fly killer, aerosols, cleaning products
  • Garden chemicals – e.g. snail/slug poison, weed killer, fertilizers, insecticides, pool chemicals
  • Antifreeze
  • Foods – e.g. Chocolate, raisins/grapes, foods containing xylitol sweetener, alcohol, macadamia nuts

There is also limited information that rosemary may cause seizures in dogs, and therefore worth considering if your dogs regular diet and/or treats contain rosemary as a natural preservative.

Also note if your dog has received any recent medications or vaccinations, including any flea/worming treatments. Several flea treatments such as Bravecto, Nexgard and Simparica now have a warning regarding adverse effects in some dogs. See the FDA Flea/Tick adverse events

Milbemax worming treatment also states muscle tremors, ataxia and convulsions can occur as a rare side effect and is therefore also worth noting if there is any associations with the timing of medications and seizures.

Long Term Management

Once all underlying causes have been ruled out and/or investigated and treated, if no cause has been found a long term management strategy will be required.

Your vet/neurologist will determine whether anti-epileptic medication is required depending on the frequency and severity of seizures.

If your dog is prescribed anti-epileptic medication, make sure you give it consistently at the same time every day. There are a number of different medications available, do not make changes to medication unless under the guidance of your vet.

Dietary Changes

The Royal Veterinary College (RVC) did some interesting research into adding MCT oil to the diet. The MCT oil used in the research was a commercially available dietary supplement suitable for human consumption containing 50%-65% octanoic acid (C8) and 30%-50% decanoic acid (C10). Overall, the RVC research found that dogs had significantly fewer seizures with MCT oil, and an improved quality of life. The research article can be found on the following link: A multicenter randomized controlled trial of medium‐chain triglyceride dietary supplementation on epilepsy in dogs. Talk to your vet/neurologist about the possible benefits of adding MCT oil to the diet.

Buyer Advice

Advice for Puppy Buyers

Unfortunately there are currently no health screening schemes available that test whether a dog is genetically affected or carrying epilepsy, and it can also occur at any age. However the breeder should be aware that it may occur, and be able to talk to you about epilepsy and what measures have been taken to avoid it in their breeding plans.

 

Breeder Advice

Advice for Breeders

Epilepsy is a difficult condition about which to give breeding recommendations. It is currently not possible to determine the mode of inheritance, however it appears to be inherited in a complex manner, with potential environmental and non-genetic risk factors in some, but not all, cases. For complex conditions, breeding decisions in many ways become about risk management. At the very least it would be unwise to repeat a mating which has produced puppies that have gone on to be diagnosed with idiopathic epilepsy.

The KC website provides general guidance for complex inherited diseases where no test is available such as some forms of epilepsy. The guidelines may be useful in formulating an action plan as a way forward, however whilst the information may help reduce the risk of producing affected puppies, it cannot be used as a guarantee.

A summary of the guidelines is provided below:

Breeding from an affected dog

  • Not recommended

 

Breeding from an unaffected dog that already produced affected puppies

  • Do not repeat a mating that produced affected offspring
  • If the dog is unaffected themselves if choosing an alternative mate, ensure there is no record of the condition in their line, paying particular care to immediate relatives

 

Breeding from an unaffected dog with affected siblings or parent

  • Only consider breeding later on in life, ensuring the dog does not become affected later.
  • Choose a mate where there is no record of the condition in their line, paying particular care to immediate relatives.

 

Breeding from an unaffected dog with affected distant relatives

  • Choose a mate with no record of the condition in their line, paying particular care to immediate relatives.

 

Unaffected dogs with no history of affected relatives

  • Low risk

Regarding breeding later on in life to ensure the dog does not become affected later,  information provided by the Giant Schnauzer seizure study analysis may be useful in determining the minimum age after which the risk of developing epilepsy may begin to reduce. In females the incidence appears to reduce slightly after the age of 2 years and in males after the age of 3 years, in both males and females the risk is reduced further after the age of 6 years. However, the statistics also show that seizures have been known to occur beyond these ages in some cases and therefore provides no guarantee. Consideration should also be given to dogs producing epilepsy when mated to more than one breeding partner, and whether it is wise to continue breeding from a dog associated with multiple instances of epilepsy.

The inbreeding coefficients of affected Giant Schnauzers vary from as high as 20% in a number of dogs down to 0.6%. This shows that utilising a breeding strategy based solely on a low inbreeding coefficient may not necessarily suffice. Consideration for the health status of dogs on both sides of the pedigree is also required in order to manage the risk, even though breeding mates may appear to be unrelated.

How You Can Help

If you Own an Affected Dog

Inform the breeder and keep them up to date with your dog’s progress, the breeder will need to be aware for future reference and breeding decisions.

Please take part in the Epilepsy/Seizure Study

If you own a Giant Schnauzer with epilepsy, please take part in the Epilepsy/Seizure Study.

In this way the incidence of health conditions can be monitored and any emerging problems identified.

 

Make a Donation to the GSHF

The purpose of the GSHF is to provide monies for research into inherited health problems in the Giant Schnauzer. All donations gratefully received.

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