|Epilepsy generally starts in dogs 6 months to 5 years of age, usually at 2-3 years.|
Epilepsy is a disorder of recurring seizures. Seizures are described as an uncoordinated firing of the neurons usually within a portion of the brain called the cerebrum. The mechanisms of why these neurons do not function normally is not understood, but is similar if not identical to the causes in humans. Probably certain substances called neurotransmitters are not in the proper chemical balance, so the nerves do not behave in the normal coordinated fashion. A patient with epilepsy will exhibit periodic bouts of uncoordinated firing of the neurons within the brain. These episodes are called seizures and occasionally referred to as convulsions or "fits."
Causes of seizures
When a vet is first presented with a patient that has had a seizure, initially they will attempt to find the cause. Seizures can be caused by many conditions:
Types of seizures
Partial seizures affect only a small part or one side of the body. These are often caused by a brain lesion.
Generalised seizures affect the whole body and can be divided into two types, grand mal and petit mal. Grand mal seizures are the most common. A patient experiencing a grand mal seizure usually falls on her side and has uncontrollable muscle activity such as kicking her legs as if swimming or paddling. Salivation is profuse and often the patient involuntarily urinates and defecates. The patient is unaware of you, her surroundings, or her own actions. Petit mal seizures do not result in convulsions, but the animal loses consciousness. It may look like the animal just collapsed.
The worst form of seizure is one in which the patient exhibits one or more grand mal episodes without recovering from the first. This patient may actually be in a seizure for hours. This is termed Status Epilepticus and is usually referred to simply as Status. Seizures by themselves are not life threatening unless they progress into Status, in which case medical attention should be sought immediately.
What are the phases in a seizure?
If you observe closely, you can often recognize three phases to a seizure.
Pre-Seizure Phase: The pre-seizure phase is commonly called the aura. Your pet may appear restless, pace, seek affection, salivate, whine, or hide. These signs occur just minutes before the actual seizure begins.
Ictus: The seizure itself is called ictus. Your pet may appear excited, vomit, salivate, run in circles, collapse, and have uncoordinated muscle activity. This stage generally lasts less than 5 minutes.
Post-Ictal Phase: After the seizure, the recovery (post-ictal) period begins. Your pet may seem disoriented, uncoordinated, and occasionally blind (temporary). This may last several minutes to days.
Rarely does a patient become vicious during a seizure. In fact, most patients will actually feel the seizure coming on and seek out the owner for comfort. During the actual seizure, a patient is unaware of his surroundings so it does little good for the owner to try to comfort the seizuring patient. It is best to be there for comfort when the pet recovers.
What triggers a seizure?
The actual triggering of a seizure is unknown, but most patients tend to seizure during periods of excitability. Often, the owner will state that the patient seizures while playing ball or when the children returned home from school. We had one patient who seizured the day after visiting our veterinary hospital, no matter what the reason for the visit. Some patients have been known to seizure while sleeping. Please do not confuse this with dreaming, where it is common for the patient to bark or shake while sleeping. A dreaming patient can be awakened, but a seizuring patient cannot.
How is epilepsy diagnosed?
First, a detailed history is needed. A physical and neurologic exam are performed by your veterinarian, a panel of laboratory tests are run, and sometimes x-rays (radiographs) are taken. If a cause of the seizure can not be identified, the condition is diagnosed as idiopathic or primary epilepsy. There is no test to diagnose epilepsy per se, our tests simply rule out other causes of seizures.
What type of information can the owner provide to help the veterinarian make the diagnosis?
It is helpful if you, the owner, can give your veterinarian answers to the following questions:
Are some animals more prone to epilepsy?
Epilepsy generally starts in animals 6 months to 5 years of age, usually at 2-3 years.
Epilepsy occurs in all breeds, including mixed breeds. Epilepsy can be a genetic trait. It can even be familial where the epileptic disorder can pass down through generations within one family. Beagles, German Shepherds, Irish Setters, Poodles, Saint Bernards, Springers, Malamutes and Huskies, Cockers, Collies, Dachshunds, and Golden and Labrador Retrievers are some of the breeds which have a higher tendency to develop epilepsy. It is recommended that dogs with epilepsy should not be used for breeding, since this tendency can be inherited.
How is epilepsy treated?
Treatment for epilepsy is usually not begun until a seizure is severe or multiple seizures have occurred and a pattern is observed. It is very important to know the pattern of seizures in your pet so your veterinarian can determine if the treatment is helping.
TREATMENT IS NEVER CURATIVE. The goal is to decrease the frequency, severity, and duration of the seizures.
Medications used to treat epilepsy are given orally. Each animal reacts differently to the medications. Your veterinarian may need to try different types or combinations to find what will be right for your pet. Many pets will become sleepy when they first start medication, but this soon wears off after several weeks.
The drug most commonly used to control epilepsy is Phenobarbital. Dilantin and Primidone are other drugs used in veterinary medicine. All are phenobarbital-related drugs. These medications must be given every day. These medications are classified as sedatives in which case the objective is to sedate the neurons of the brain, but not to the point where the patient becomes obviously sedated or "dopey." In the normal patient receiving these drugs, you can seldom detect that the dog is on any medication. These are the same medications used in humans with epilepsy and the goal of treatment is the same. Other medications, such as potassium bromide (KBr), clorazepate, phenytoin and clonazepam, dimethylglycine, and felbamate may be used alone or in combination with phenobarbital, if phenobarbital alone is not effective. Once medication has started it is IMPORTANT to NOT suddenly discontinue or 'skip' a dose of medication. Severe seizures could result.
If a patient experiences prolonged seizures referred to as Status, injectable drugs such as valium are administered intravenous for rapid effect.
Phenobarbitol and related anti-epileptic drugs can have side effects on the liver, especially if high dosages are required. We usually suggest liver function tests before we adjust dosages upward. Although this is a good practice, it is very rare to see liver damage even at high levels.
It is common for one dosage level of medication to work for a period of time, then have the seizures increase in length or frequency. In these cases, the drug dosages may be adjusted. If the treated patient goes months with no seizures, then we may try a lower dosage, which may still control the seizures. We might add here that we have all of our clients keep a calendar or log of the seizures, recording the date and length of time they lasted. This makes it easier for us to determine if adjustments are necessary. Obviously, the owner may miss some episodes, since they can not watch their dog every minute, but the calendar is beneficial.
What should I do if my pet has a seizure?
Do not put your hand in your pet's mouth. This will not help your pet and you may be bitten. (Contrary to popular belief, a dog will not swallow his tongue.)
To prevent injury to your pet, remove nearby sharp or hard objects (e.g.; tables and chairs).
Observe your pet closely. Call your veterinarian if the seizure lasts more than 20 minutes, or if your pet has one seizure right after another. Severe and long seizures are a medical emergency and can be fatal.
A single, mild seizure is not an emergency and rarely indicates the need for long-term treatment. But at a convenient time, you should call your veterinarian and report what occurred. Be sure to record the date, time, and duration of any seizure.
Further info on Epilepsy can be found here: http://www.canine-epilepsy.net/basics/basics_index.html
& here http://www.canineepilepsy.co.uk/