Seizures in Dogs
December 4, 2021
Witnessing your dog experience a seizure is extremely upsetting, but despite the violent display, these episodes are not painful. A seizure is uncontrolled electrical activity between brain cells that causes temporary irregularities in behavior, sensation, consciousness, and muscle tone or movement. They are a sign indicating abnormal motor activity in the brain.
What causes seizures in dogs?
Identifying a seizure’s cause is not always possible, but the episode can typically be classified as reactive, structural, psychomotor, or idiopathic.
- Reactive seizures — Dogs experiencing a reactive seizure have a normal brain, and the seizure results from a metabolic abnormality or toxicity. Common toxins that cause seizures include:
- Medications (e.g., ivermectin, ibuprofen, and diphenhydramine)
- Plants (e.g., mushrooms, brunfelsia, and sago palm)
- Foods (e.g., xylitol, caffeine, and dark chocolate)
- Pesticides (e.g., strychnine, metaldehyde, and bifenthrin)
- Illicit drugs (e.g., cocaine, amphetamines, and synthetic cannabinoids).
- Structural epilepsy — When a dog’s seizure is caused by a brain malformation or trauma, the diagnosis is structural epilepsy. In dogs older than 6 years, seizures are usually caused by a tumor growing from the skull that is pressing on the brain. Meningiomas are the most common tumor type.
- Psychomotor seizures — These seizures appear more like abnormal behavior than a convulsion. They are focal seizures that disturb the dog’s consciousness, and cause them to hallucinate or become disoriented.
- Idiopathic epilepsy — This is the most common reason dogs, especially purebred dogs 6 months to 6 years of age, seizure. Idiopathic epilepsy appears to be genetic, but the exact cause is unknown. Schnauzers, basset hounds, collies, and cocker spaniels are predisposed to idiopathic epilepsy.
What happens when a dog seizures?
Three phases typically occur when a dog has a seizure. These include:
- Pre-ictal phase (aura) — Preceding the seizure, dogs usually exhibit altered behavior, such as nervousness, hiding, salivating, or seeking their owner’s comfort. This phase can last seconds or hours.
- Ictal phase — During a generalized seizure, the dog will lose consciousness, and their muscle movements will become spastic and erratic. They will typically fall on their side and paddle their limbs, while drawing their head back. Urination, defecation, and salivation commonly occur. During a focal seizure, the changes will be milder and may include your pet looking dazed, licking their lips, moving their mouth as if they were chewing gum, or staring aimlessly. This phase can last from a few seconds to several minutes.
- Post-ictal phase — Following a seizure, dogs may exhibit signs that include confusion, disorientation, salivation, pacing, restlessness, or temporary blindness. The seizure’s severity does not correlate to the time the post-ictal phase lasts.
Seizure types in dogs
The most common seizure type in small animals is a generalized (i.e., grand mal) seizure, which involves both sides of the brain, with clinical signs that involve the entire body. Focal seizures, which begin in a discrete brain location, are characterized by clinical signs that affect a single side or specific body part.
Seizure frequency classification in dogs
Seizure frequency is one of several factors considered when determining when to start anticonvulsant medication. These classifications include:
- Cluster — The classification made when a dog experiences three or more seizures in a 24-hour period
- Acute repetitive — The classification made when your dog has two or more seizures in 5 to 12 hours
- Status epilepticus — The classification made when a dog seizures for five minutes or more—a dog experiencing status epilepticus is at risk for developing hyperthermia, a life-threatening condition. If status epilepticus occurs, immediate veterinary attention is required.
What should I do if my dog has a seizure?
You cannot stop a seizure, but you can take steps to keep your dog safe until the seizing stops. These include:
- Do not panic – Remaining calm and focused will allow you to assist your dog, and relay necessary information to your veterinarian.
- Time the seizure — Knowing the seizure’s duration will provide useful information when your veterinarian is evaluating the situation. If possible, have someone video the episode, so you can show your veterinarian the actual seizure.
- Do not grab your dog’s tongue — When a dog seizes, they do not swallow their tongue. If you attempt to grab their tongue, you could be bitten.
- Prevent trauma — To prevent your dog from self-injury during a seizure, cushion their head, and keep them away from stairs and hard objects.
- Prevent hyperthermia — If your dog continues to seize after two to three minutes, apply wet towels around their neck and body, and get them to a veterinarian immediately.
- Call your veterinarian — Once the seizure is over, call your veterinarian for advice. If your dog seems completely normal after the seizure, you should still contact your veterinarian and explain the episode.
- Document the episodes — Start detailing your dog’s seizures, including the dates, time, and length, to help your veterinarian determine any pattern to the seizures.
How are seizures diagnosed in dogs?
After your dog has a seizure, your veterinarian will ask for a detailed history, focusing on any toxin exposure or possible head trauma they may have experienced.
Your veterinarian will perform a thorough physical examination, and conduct other diagnostics, such as blood tests and a urinalysis, to rule out issues involving the liver, kidneys, heart, electrolytes, and blood sugar levels. If no abnormalities are found, you will likely be instructed to closely monitor your dog, and call immediately if they suffer another seizure.
Seizures that occur no more than once a month are not so concerning, but they can become more frequent and severe. If this occurs, a spinal fluid analysis may be performed, and if a referral center is an option, a computed tomography (CT) scan or magnetic resonance imaging (MRI) may be recommended.
How are seizures treated in dogs?
If your dog has a solitary seizure, they may not require treatment. A consensus statement published by the American College of Veterinary Internal Medicine (ACVIM) recommends medication to suppress seizures when a dog meets the following criteria:
- They have more than three seizures in a 24-hour period (i.e., cluster).
- They have two or more isolated seizures in a six-month period.
- They have a seizure lasting more than five minutes.
- Their seizure or post-ictal phase was particularly severe.
- They have a visible structural lesion seen on CT or MRI.
- They have experienced brain trauma.
- They are a German shepherd, border collie, Australian shepherd, golden retriever, Irish setter, or Saint Bernard, breeds that are notorious for difficult seizure control. The more seizures they experience, the more difficult control becomes, and medication therefore should be started after the first seizure.
Most dogs who are placed on anticonvulsant treatment must be kept on the drug for life. If the medication is discontinued, they will have a greater risk for developing more severe seizures. Never change or discontinue your dog’s medication before consulting your veterinarian.
Watching your dog affected by seizures can be frightening. While the seizures may not be completely eliminated, acceptable goals may include decreased frequency, decreased severity, or decreased duration. The main goal is that the dog’s quality of life is improved.
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