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Seizures in Dogs: An Overview

Seizures in dogs have various causes.

A seizure is a behavior or body movement that happens unintentionally. It is caused by abnormal activity in your dog's brain and has many potential causes. If your dog has suffered from a seizure, you have probably felt afraid and may not have known what to do. Here, we explore the types of seizures in dogs, their signs, causes, diagnosis, and treatment.

Types of Canine Seizures

There are three main types of seizures in dogs.

  • Partial seizures. A limited area of the body is affected by this type seizures. It often involves a twitch or bigger contraction of a certain muscle group or area. This may also be called a petit mal or focal seizure.
  • Grand mal seizures. This is the most common type of seizure seen in dogs. The entire body becomes stiff, the dog isn't able to stand, and there is often rhythmic movement of muscles. A paddling motion of the legs is often seen, and the dog is not conscious during the seizure. It's quite common for a dog's bladder and/or bowels to be released during a grand mal seizure.
  • Psychomotor seizures. These types of seizures consist of sudden abnormal behavior such as snapping, snarling, or circling. They may be followed by a grand mal seizure. They may also be referred to as complex seizures.

The Three Phases of a Seizure

Seizures occur in three phases.

  • The pre-ictal phase. This occurs just prior to a seizure. Humans describe disorientation, seeing an aura, or other feelings that only occur just before a seizure event. In animals, it may be difficult to discern a pre-ictal phase. However, some dog owners can pick up on certain behaviors that always seem to occur right before a seizure. For instance, some dogs seek out their owner, acting clingy or nervous.
  • Ictus. This is the seizure itself. Animals may show any of the signs associated with the 3 types of seizures listed in the section above.
  • The post-ictal phase. This is the period after the seizure. It may involve temporary blindness, disorientation, stumbling, and panting. It may last anywhere from a few moments to several hours after the seizure.

Causes of Seizures in Dogs

The possible causes of canine seizures are many, but they fall into 3 main groups:

  • Brain-centered. These seizures are caused by a problem in the brain itself. Infections, trauma, defects in the way the brain or spinal cord are formed, and tumors can all directly affect a dog's brain and cause dysfunction that results in seizures. These types of convulsions are sometimes called secondary seizures.
  • Outside of the brain. These seizures are caused by an issue outside of the brain. Low blood sugar, liver failure, poison ingestion, kidney failure, and hypothyroidism are some examples of things that are not directly within the brain but can cause neurologic dysfunction resulting in seizures. These types of convulsions are sometimes called reactive seizures.
  • Unknown causes. When a cause for a dog's seizures can't be identified, it is usually diagnosed as idiopathic epilepsy or just epilepsy. These are also sometimes called primary seizures, and most scientists suspect a genetic basis for this disorder.

Diagnosis of Seizures in Dogs

If your dog has not had a seizure in front of your veterinarian, a tentative diagnosis is made based on your explanation of what happened. Because some other conditions can cause signs that may be confused for seizure activity, your veterinarian may ask you some specific questions about how your dog acted before, during, and after the episode. This will help the doctor narrow down whether your dog had a seizure or some other medical event. Some things that can sometimes be confused for seizures include:

  • Vestibular disorder
  • Fainting
  • Dreaming

Your veterinarian will do a thorough examination of your dog if he or she suspects that a seizure occurred. A basic neurological exam will be conducted to determine if there are any deficits.

Your veterinarian may recommend blood work to eliminate possible issues outside of the brain such as low blood sugar, infection, or organ function problems that may cause seizures. A CSF (cerebral spinal fluid) tap may be necessary if the doctor suspects an infectious cause for the seizures.

If your veterinarian is concerned about a brain tumor, a CT or MRI scan may be required to diagnose the problem.

Treatment of Canine Seizures

Treatment for seizures in dogs depends on the cause. For instance, trauma may require supportive care, bacterial infections might be treated with antibiotics, tumors require surgery, low blood sugar must be corrected, and liver or kidney failure may be able to be managed with diet, medications, supplements, and fluid therapy.

Sometimes, anticonvulsant medications are required along with other treatment or as the primary treatment in cases of epilepsy, where a specific cause can't be determined.

Anticonvulsant Therapy for Seizure Disorders in Dogs

The most common anticonvulsant used in dogs with seizure disorders is phenobarbital. It is fairly inexpensive and works well in the majority of canine epilepsy cases. However, there are some things to know about treatment with this drug:

  • Phenobarbital must be present at a certain level in the blood for it to work. If there is not enough, it is not able to control seizures, and if there is too much, unwanted side effects such as liver dysfunction can occur. Because of these considerations, phenobarbital is a drug that must be monitored with periodic blood work. Initially, a dog's blood phenobarbital level should be tested 2 to 4 weeks after beginning the medication. If an adjustment is necessary, blood work should be repeated in another 2 to 4 weeks. Once the phenobarbital level is stabilized, it should be checked every 3 to 6 months, and general blood work should be checked every 3 to 12 months based on individual circumstances.
  • Phenobarbital can cause sedation initially. Dogs may be quite tired and inactive for a few days to a week after beginning the drug. After that, most dogs' systems adjust to the medication and their activity levels return to normal.
  • Some dogs become excessively thirsty and hungry on phenobarbital. When this occurs, it is necessary to reduce the amount of the drug that is given and add a second medication, usually potassium bromide, to control the seizures without this side effect.
  • Phenobarbital may cause liver problems in some dogs. These dogs may not be able to take the drug or may need to take less and be placed on a second anticonvulsant such as potassium bromide along with it.
  • Adequate seizure control on phenobarbital alone is not achieved in 20-30% of canine patients, even when their blood levels are therapeutic. These dogs generally require a lower dose of phenobarbital and the addition of potassium bromide.

If phenobarbital +/- potassium bromide doesn't control a dog's seizures or produces undesirable side effects, there are some human medications that are sometimes used in dogs. These include Keppra®, Zonegran, and gabapentin. These drugs can be expensive and have dosing schedules that are difficult for some people to manage, but they are possibilities in certain cases. Never give your dog any medications without speaking with your veterinarian first.

When Is Treatment Necessary?

Not all dogs that have seizures need to be treated with anticonvulsant medications. Most veterinarians agree that the side effects and expense of the drugs outweigh the risk that the seizures pose for the animal if episodes are infrequent and mild. Below are the criteria used by many veterinarians to determine when an owner should consider treating their dog with medications like phenobarbital.

  • Seizures occur more than once a month. If seizures are less frequent than that, many veterinarians recommend monitoring and recording them but not treating them.
  • Your dog experiences cluster seizures. When 2 or more seizures occur immediately after one another, it is termed cluster seizing, and many veterinarians recommend treating dogs in which this occurs.
  • Special circumstances exist. If a dog is frequently alone or some other special condition exists in the household that makes it difficult for an owner to adequately monitor her seizures, treatment may be recommended even if the episodes are infrequent.
  • Seizures last more than 5 minutes when they occur. If your dog tends to have long seizures when they do occur, your veterinarian will probably want to treat them, even if they are infrequent. These dogs may be prone to a dangerous condition called status epilepticus, which is a continuous seizure that doesn't stop on its own, and these can be life-threatening.
  • Your dog is a certain breed. Some dog breeds have more trouble obtaining seizure control than others, and your veterinarian might want to start treatment right away in those dogs, even if the seizures are still infrequent. These breeds include golden retrievers, German shepherds, and Irish setters.

What Should You Do If Your Dog Has a Seizure?

It can be quite upsetting to see your dog have a seizure. It helps if you know what to do.

  • Look at your watch. Begin timing the seizure when your dog is in ictus (involuntary movements, does not seem to know what's going on). If your dog is still seizing after 5 minutes, you should get emergency help from a veterinarian. Do not count the pre- or post-ictal periods in your time. If you don't actually look at a clock, it is likely that it will feel to you as though the seizure lasts longer than it really does.
  • Keep the area safe. Try to keep your dog from crashing into anything or falling down stairs. You need to be as careful as possible to avoid being hurt yourself. Your dog will not be aware of her surroundings, and she may inadvertently bite, scratch, or otherwise injure you. You do not need to attempt to pull your dog's tongue forward. Doing so will almost certainly get you injured. Your dog may need to be confined during the post-ictal phase of the seizure, as well, because some animals try to walk around then but are unstable and may fall down stairs or crash into furniture.
  • Consider recording the episode. If your dog has not already been diagnosed with seizures, you may wish to record the episode to show your veterinarian. This can be especially helpful in cases where it is not a full-blown, obvious grand mal seizure. You should only consider recording once you know your dog is safe and you have looked at your watch.

If your dog has a history of having serious, long, or cluster seizures, your veterinarian may prescribe you some liquid Valium that you can apply rectally to help stop a seizure or prevent another one from occurring soon after the first.

Final Thoughts

Most of the time, seizures won't result in any lasting damage to your dog. It can be upsetting to see a seizure occur, but remember that most dogs recover quickly. An exception is if the seizure is long because your dog's body temperature may increase to the point where brain or organ damage can occur. Another dangerous situation is when a dog has more than one seizure back-to-back. This is another time when her increased body temperature could result in lasting damage. Knowing the signs of a seizure, what to do when your dog has one, and when it is an emergency can help you stay calm and keep your dog safe.


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