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Epilepsy

Watching a beloved dog endure a seizure is heartbreaking.

The day to day medication and above all continuous observation is exhausting and stressful but of course we continue as long as we can to offer a good quality of life for our dogs that suffer visits from “the monster” of epilepsy.

Our Health Co-ordinator is Lynne Dale.

Contact Lynne Dale 01924 255590

What is a seizure? 

Seizures are one of the most frequently seen neurological problems in dogs. A seizure is also known as a convulsion or fit. It may have all or any combination of the following: 

1. Loss or derangement of consciousness 

2. Contractions of all the muscles in the body 

3. Changes in mental awareness from non-responsiveness to hallucinations 

4. Involuntary urination, defecation, or salivation 

5. Behavioural changes, including non-recognition of owner, viciousness, pacing, and running in circles

What are the three phases of a seizure? 

Seizures consist of three components: 

1. The pre-ictal phase, or aura, is a period of altered behaviour in which the dog may hide, appear nervous. or seek out the owner. It may be restless, nervous, whining, shaking or salivating, This may last a few seconds to a few hours. 

2. The ictal phase is the fit or seizure itself and lasts from a few seconds to about 5 minutes. During this period, all of the muscles of the body contract strongly. The dog usually falls on its side and seems paralysed while shaking. The head may be drawn backward. Urination, defecation, and salivation often occur. If it is not over within 5 minutes, the dog may be in status epilepticus or going from one seizure into another without respite. 

3. During the post-ictal phase. there is confusion, disorientation, salivation, pacing, restlessness, and/or temporary blindness. There is no direct correlation between the severity of the seizure and the duration of the post-ictal phase. 

Is the dog in trouble during a seizure? 

Despite the dramatic signs of a seizure the dog feels no pain, only bewilderment. Dogs do not swallow their tongues. If you put your fingers into its mouth, you will do no benefit to your pet and will run a high risk of being bitten very badly. The important thing is to keep the dog from falling and hurting itself. As long as it is on the floor or ground. there is little chance of harm occurring. If seizures continue for longer than a few minutes, the body temperature begins to rise. If hyperthemia develops secondary to a seizure, another set of problems may have to be addressed. 

What causes seizures? 

There are many of seizures. Epilepsy is the most common and of least consequence to the dog. The other extreme includes severe diseases such as brain tumours. fortunately, most are due to epilepsy.

Now that the seizure is over, can anything be done to understand why it happened? 

When a seizure occurs, we begin by taking a thorough history concentrating on possible exposure to poisonous or hallucinogenic substances or history of head trauma. We will also carry out a full physical examination including blood tests and an electrocardiogram (EGG). These tests rule out disorders of the liver. kidneys, heart, electrolytes, and blood sugar level. If these tests are normal and there is no exposure to poison or recent trauma. under these circumstances we may refer you to a veterinary neurologist for further tests and examinations which could, conceivably, involve more sophisticated tests including MRl, CAT scans and an electroencephelogram. Fortunately, these additional tests are usually not needed. 

What can be done to prevent future seizures? 

We generally prescribe 1-2 weeks of anticonvulsant therapy. If there are no more seizures during that time. the anticonvulsants are then gradually discontinued. The next treatment is determined by how long it takes for another seizure to occur. That may be days, months, or years. At some point, many dogs have seizures frequently enough to justify continuous anticonvulsant therapy. Since that means that medication must be given every 12 to 24 hours for the rest of the dog’s life, we do not recommend that until seizures occur about every 30 days or unless they last more than 5 minutes. 
It is important to avoid sudden discontinuation of any anticonvulsant medication. Even normal dogs may be induced to seizure if placed on anticonvulsant medication and then abruptly withdrawn from it. This would be fully discussed with you. 

You mentioned status epilepticus. What does that mean? 

Status epilepticus bears special note. It is characterised by a seizure that lasts more than 5 minutes. When it occurs, the dog’s life is endangered. Unless intravenous medication is given promptly, the patient may die. If you think your dog is in status, you should seek treatment immediately. 

Extracts from veterinary practice leaflets kindly supplied by F.J. Marshall BVMS MRCVS Castle View Veterinary Clinic, Wakefield

 

 

From Professor Ed Hall–JISBC Health Coordinator

November 2013

Epilepsy is characterised by recurrent seizure activity (fits), and is the most common chronic neurological problem in dogs. It has been estimated to affect 0.6% of the canine population, and there are some clear breed predispositions, with an increased risk identified in Beagles, Border collies, German shepherd dogs, Labrador retrievers and Golden retrievers, for example. Inheritance has been demonstrated in several breeds, although the exact genetic defect has yet to be elucidated, and indeed may be different in unrelated breeds.  It seems likely that mutations in the ion channels in nerves that help conduct electrical impulses alter the excitability of nerve pathways, and when a certain excitement  threshold is reached a full seizure occurs.

The condition is more common in male dogs (1.5 x risk), and typically first occurs between six months and six years of age. Seizures in younger dogs are more likely caused by developmental  brain problems such as hydrocephalus, or metabolic problems such as liver shunts; seizures in older dogs are more likely associated with brain tumours, although late-onset epilepsy is possible.

The cause of true epilepsy is unknown; it is often called idiopathic epilepsy to distinguish it from other causes of seizures, such as previous brain trauma, hydrocephalus and metabolic causes. An association between seizures and hypothyroidism has been suggested, but hypothyroidism is more typically a disease of older dogs, and thyroid hormone supplementation is rarely successful in treating epileptic dogs, although testing thyroid function could still be considered.

Epileptic seizures are preceded by a short period of abnormal behaviour (the aura phase) and most often happen when the dog is resting.  Typically they involve loss of consciousness, paddling of limbs and loss of bowel and bladder control, although partial seizures can occur. Although to an owner observing their dog, the fit seems to last for ages, most only last less than two minutes. During this time the dog should be kept safe, but it is helpful if owners try to record the duration of the fit and what happened during it, rather than trying to pull the tongue out of the mouth, which is dangerous and should not be attempted. After a seizure (the post-ictal phase) the dog may be depressed and disorientated for a few hours to days. In between seizures, a true epileptic will be neurologically normal; if there are persistent nerve deficits another cause is more likely.

Epilepsy is a serious problem that affects the quality of life of both the dog and its owner, and can cause premature death. Dogs with frequent seizures (two or more isolated seizures in a six-month period, or infrequent clusters of seizures) or which develop a continuous seizure (‘status epilepticus’) require treatment, and yet approximately 60% will continue to have some seizures, and about one‑third do not achieve adequate control (i.e. a 50% reduction in seizure frequency) with treatment.

First-line treatment is usually with phenobarbitone or with a new (and potentially safer) drug called imepitoin (Pexion).  Phenobarbitone often causes sedation and increased appetite and thirst initially, but this soon wanes.  However, chronic therapy at high doses can cause liver damage. If neither drug produces adequate control , potassium bromide may be added.  Periodic monitoring of drug levels is essential. If no seizures occur for two years, medication may be withdrawn although this must be done gradually to avoid precipitating more seizures.

Finally, concern has been expressed that the prevalence of epilepsy is increasing in Irish setters and a familial basis is suspected.  So studies are underway in Finland to try to identify an underlying genetic mutation. However, the exact numbers of epileptics in Irish setters is currently unknown, although it is hoped that, as one of the supplementary questions in the AHT/KC Bloat survey, more accurate data will soon be available.

Professor Ed Hall

 

Continuing with research into canine idiopathic epilepsy at the Royal Veterinary College, the Clinical Investigation Centre and the Epilepsy Clinic at the RVC is working with a small animal health and wellness company to confirm the efficacy and safety of a novel diet in the management of dogs with idiopathic epilepsy being treated with phenobarbitone and/or potassium bromide.
The influence of diet on epilepsy severity is established in humans, with many diets having been shown to improve seizure control. However, there is little data to support the use of diets in veterinary medicine. A new diet has been developed which could improve the management of epileptic dogs, not only by reducing seizure frequency, but also by decreasing the level of side-effects seen with standard antiepileptic drugs.
To confirm the efficacy of this new diet, we would like to recruit dogs which are suspected of having idiopathic epilepsy.
Dogs which have a seizure frequency of at least three seizures in the last three months.
Dogs receiving phenobarbitone and/or potassium bromide treatment.
Client incentives:
1.A comprehensive investigation of the idiopathic epilepsy by our neurologists Ms Emma Davies or Dr. Holger Volk with a special interest in this field.
2.Free diagnostic tests including haematology, biochemistry, metabolic profiling and a dynamic bile acid test.
3.Serum phenobarbitone and potentially potassium bromide concentrations will be assessed.
4.A six month supply of dog food.

Inclusion criteria:
1.Dogs suspected of having idiopathic epilepsy.
2.Unremarkable MRI and CSF analysis.
3.Dogs aged ≥6 months and ≤11 years.

Canine idiopathic epilepsy: The influence of a diet on improving seizure control.

Sharing passions, Shaping futures
For further information please contact:
The Clinical Investigation Centre Tel: +44 (0) 1707 666605
Royal Veterinary College, Fax: +44 (0) 1707 666223
Hawkshead Lane, North Mymms,Email: cic@rvc.ac.uk
Hertfordshire AL9 7TA

 

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