Seizures in Dogs

What is a seizure?

A seizure occurs when brain neurons spontaneously begin to fire excessively and simultaneously. When seizures occur, your dog may salivate, vomit, urinate, defecate, vocalize, twitch, tremor, collapse, and/or convulse. During this time, animals may have disturbances of their senses.

Seizures can last anywhere from a few seconds to minutes, and in severe uncontrolled cases, for hours. Some dogs have seizures without their owners even realizing it, and others can even lose consciousness.

Types of Seizures

Focal/partial seizures (petit mal)

• Twitching of eyelids, lips, ears (on only one side of the body)
• Abnormal limb movements
• May remain conscious
• If persisting without intervention, can become a generalized seizure/worsen

Generalized seizures (grand mal)

• Sudden loss of consciousness
• Motor activity in limbs - intermittent flexing and extending
• Loss of bladder and bowel control - urination, defecation
• Pupil dilation
• Vocalization – crying, howling, barking, meowing
• Autonomic nervous system activity – drooling, vomiting, diarrhea

Seizure Stages

1. Prodrome: behavioral changes that occur just minutes or hours (or even days) before the seizure
2. Ictus: the seizure itself
3. Post-ictal Stage: the period of recovery after a seizure, subtle or obvious, can involve dementia, pacing, hyperactivity, etc.

Causes of Seizures in Dogs

• Reactive Seizures: caused by either metabolic diseases or toxicities
• Structural Epilepsy: caused by degenerative diseases, congenital anomalies, cancer, infectious diseases, trauma, and strokes
• Epilepsy: recurrent seizures that are not caused by reactive seizures or structural epilepsy
  • Genetic Epilepsy: known genetic causes (human research indicates genetic component involved)
  • Epilepsy of Unknown Origin: no evidence to support genetic epilepsy and proven not to have reactive seizures or structural epilepsy (ruled out by testing)

Foods That Can Cause Seizures in Dogs

Not all toxic food products trigger seizures in dogs. The most common foods that cause dogs to have seizures include:

1. Xylitol

Xylitol is a popular sugar substitute that is being used in sugarless candy, chewing gum, medicines, vitamins, and other products.

The symptoms of xylitol poisoning are associated with a sudden dip in the blood sugar of dogs and include:

• Weakness
• Inactivity
• Staggering
• Incoordination
• Seizures
• Collapse

2. Chocolate and Caffeine

Chocolate and caffeine contain substances called methylxanthines. Caffeine is found in coffee, tea, and as an additive in many soft drinks. Caffeine is also used in certain human medications to act as a mental stimulant. Chocolates also contain theobromine, a plant-derived alkaloid that is present in substantial quantities in cacao seeds.

Signs of chocolate and caffeine toxicity in dogs are similar and usually exhibited within 2-4 hours of ingestion. These include:

• Vomiting and diarrhea
• Panting
• Excessive thirst and urination
• Abnormal heart rhythm
• Tremors
• Seizures

3. Ethanol

Accidental ingestion of alcoholic beverages is the most common cause of ethanol toxicity in dogs. Ingestion of rotten apples, sloe berries, uncooked bread, and pizza dough are also associated with ethanol toxicity. Alcohol may also be present in certain products such as mouth wash.

Once ingested, ethanol is rapidly absorbed from the dog’s gastrointestinal tract and crosses the blood-brain barrier. Symptoms of toxicity, such as loss of coordination, seizures, vomiting, drowsiness, and respiratory failure usually develop within an hour after ingestion.

4. Hops

Hops are flowers of the female Humulus lupulus plant which is used for beer brewing. More dogs are now at risk of exposure to hops ingestion as home brewing has become popular. Ingestion of fresh or spent hops can cause malignant hyperthermia in dogs. While any dog breed may be affected, some breeds are more predisposed to the condition. These include Labrador Retrievers, Dobermans, Saint Bernards, Border Collies, English Springer Spaniels, Greyhounds, and Northern breeds.

5. Salt

While commonly used for cooking, salt is potentially dangerous to dogs. Salt poisoning is associated with severe neurological symptoms, including brain swelling and seizures. It is also for this reason that salt should NOT be used to induce vomiting in dogs.

Salt is not only found in the kitchen but also in de-icers (rock salt), seawater, homemade playdough or salt dough, paintballs, and enema solutions.

6. Unripe Tomatoes and Stems

Ripe tomatoes are considered safe for dogs to eat, but consuming a large number of unripe tomatoes or their leaves and stems can lead to toxicity. In small dogs or puppies, it may only take a small amount of tomato (fruit or foliage) to result in toxicity.

Tomato contains solanine and tomatine. While it’s not toxic to humans, dogs react to solanine and tomatine with drooling, vomiting and diarrhea, confusion, lethargy, abnormal heart rate, seizures, abdominal pain, and loss of coordination. The condition is also called ‘tomatine toxicity’.

7. Rhubarb

Rhubarb, also called ‘pie plant’, contains oxalate crystals in the leaves and stalk which can be poisonous to dogs when consumed in large quantities.

When the oxalate salts are absorbed from the dog’s gastrointestinal tract, they bind with calcium in the body thus leading to a sudden drop in the body’s calcium levels. Symptoms of rhubarb toxicity in dogs include the following:

• Drooling
• Increased respiratory rate
• Weakness and lethargy
• Vomiting and diarrhea
• Increased thirst and urination
• Staggering
• Tremors
• Seizures
• Bloody urine
• Coma

8. Nutmeg

Nutmeg is commonly added to enhance the flavor of several dishes for humans. The seeds of nutmeg contain a chemical called ‘myristin’ which is toxic to dogs. The toxic dose is approximately 5 grams of the spice. Toxicity symptoms can be exhibited within 3-8 hours after consumption. Small amounts of nutmeg may cause mild stomach upsets in dogs, but ingestion of large quantities can lead to dehydration, disorientation, tremors, seizures, and death.

9. Nuts

Walnuts, macadamia nuts, and pecans are rich in fats which can cause digestive upset, pancreatitis, or gastroenteritis in dogs. These nuts are also linked to an incidence of seizures in dogs. However, it’s not the nuts that cause the seizures but the mold (mycotoxins) that grows on them. The molds produce tremorgenic mycotoxins that can cause nervous system problems including seizures in dogs.

Testing for Seizures

If your dog has a seizure, you should contact a vet right away. Your dog should receive a thorough physical exam. The vet will also discuss some of the following:

• History from the owner - determine if the pet got into a toxic cleaning product/mushroom/rat poison, etc.
• Neurologic examination
• Complete blood count, chemistry, electrolytes, urinalysis – rule out any metabolic or endocrine causes (for example, hepatic encephalopathy, swelling in the brain caused by severe liver disease/dysfunction)
• CT or MRI (advanced imaging) - evaluate the brain, looking for lesions, masses, abnormalities in structure
• CSF (cerebrospinal fluid) tap – rule out bacterial infection vs. immune-mediated causes (bloodwork can be completely normal with an infection present in the CSF)

What do I do if my dog is having a seizure?

If your pet is having a seizure for the first time, stay calm, keep your hands away from their face as they may inadvertently bite you – remember, they may have no control or awareness of what is happening to them or who you are.

Your dog may flail and injure themselves, so if you can safely tuck a pillow or blanket under their head, this may be beneficial. Immediately start timing the seizure. It may seem like hours when it’s only minutes, or minutes when it’s only seconds – when it’s your pet and you’re scared, it can seem like an eternity!

Bring your dog to the vet to evaluate the potential causes of the seizure and determine if any treatment is necessary. Treatment depends on the cause of the seizure(s). Underlying causes need to be diagnosed and treated to attempt to stop the seizures from reoccurring.

If you’ve already been to the vet and know why your dog has seizures, it can be helpful to keep a journal of dates, times, lengths, and types of seizures. This should include whether or not pre-ictal and post-ictal phases are occurring and how long they last. If your dog is on prescription medication, your pet’s response may dictate increasing or decreasing doses and medications.

If your dog has a seizure lasting longer than 5 minutes or has three seizures within 24 hours, it’s advised to go to a vet or nearby emergency clinic as soon as possible! Without treatment, seizures can continue to occur, lengthen in time, worsen in severity, and cause continued damage to the brain.

How are seizures treated?

There are medications that your vet may administer to your dog to stop an active seizure, but these are not preventative. There are anti-seizure medications that may be prescribed for you to administer to your pet daily, however, your vet will determine if this is necessary. There are side effects associated with some anti-seizure medications, and it’s a lifelong time commitment, so the decision must be made carefully based on the specific dog’s needs.

Read more:

What plants are toxic to dogs?
What foods are toxic to dogs?

First Aid & Emergency Care for Breathing Problems in Pets

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