Seizures are one of the most frequently seen neurological problems in dogs. A seizure is also known as a convulsion or fit. There may be any combination of the following:
Loss or derangement of consciousness
Contractions of all the muscles in the body
Changes in mental awareness from non-responsiveness to hallucinations
Involuntary urination, defecation or salivation
Behavioral 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:
The pre-ictal phase, or aura, is a period of altered behavior in which the dog may hide, appear nervous or seek out the owner. The dog may be restless, nervous, whining, shaking or salivating. This may last a few seconds to a few hours.
The ictal phase is the seizure itself and lasts from a few seconds to about five minutes. During this period, all of the muscles of the body contract strongly. The dog usually falls on its side and seems paralyzed while shaking. The head will be drawn backward. Urination, defecation and salivation often occur. If it is not over within five minutes, the dog is said to be in status epilepticus or prolonged seizure.
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. DO NOT put your fingers into its mouth, you will run a high risk of getting bitten. The important thing is to keep the dog from hurting itself. As long as they are on the floor, there is little chance of harm occurring.
If a seizure continues for longer than a few minutes, the body temperature begins to rise. If hyperthermia develops secondary to a seizure, another set of problems may have to be addressed.
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 poisons or hallucinogenic substances or history of head trauma. We also perform a physical examination, basic blood tests and an electrocardiogram (ECG) if heart disease is suspected. These tests rule out disorders of the liver, kidneys, heart, electrolytes and blood sugar level. Additionally, a heartworm test may performed if your dog is not taking a heartworm preventative regularly.
If these tests are normal and there is no exposure to poison or recent trauma, further diagnostics may be performed depending on the age at onset of the seizures or the severity and frequency of the seizures. Occasional seizures are of less concern than seizures that become more severe and frequent. In the instance of sudden onset of seizures in an elderly dog, or frequent or severe seizures at any age, a spinal fluid tap and fluid analysis may be performed and an MRI performed. Fortunately, these additional tests are usually not needed.
If no causes are found, and the seizures begin in a young dog, the diagnosis is termed “idiopathic epilepsy”. Dogs are generally 6 months to 6 years when seizures begin.
What can be done to prevent future seizures?
We generally prescribe anticonvulsant therapy if the dog is experiencing multiple seizures or if a single seizure was severe. If there was only a single, mild seizure, we often wait to see if more occur before suggesting long-term therapy. A “seizure diary” must be kept, recording date, time of day, and length of time your dog fitted.
The next treatment is determined by how long it takes for another seizure to occur, which could take 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 it until seizures occur about every 45 to 60 days or unless they last more than three minutes.