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A seizure or convulsion is a sudden excessive firing of nerves in the brain. It results in a series of involuntary contractions of the muscles, abnormal sensations, abnormal behaviors, or some combination of these events. A seizure can last from seconds to minutes.

The severity of the seizure can vary between a far-away look or twitching in one part of the face, to your pet falling on his side, barking, gnashing his teeth, urinating, defecating and paddling his limbs.

Seizures are symptoms of a neurological disorder.

The most common causes of seizures in young dogs (less than 1 year) may include:

Degenerative (storage diseases)
Developmental (hydrocephalus, porto-systemic shunts)
Toxic (lead, organophosphates)
Infectious (distemper or other viral, bacterial and fungal encephalitides)
Metabolic (hypoglycemia {low blood sugar}, enzyme deficiency)
Nutritional (common with intestinal parasitism)
Traumatic (acute head injury)

In dogs that are greater than 5 years, the causes may include:

Neoplasia (either primary or metastatic cancer)
Metabolic (liver or kidney failure)
Infectious (distemper or other viral, bacterial and fungal encephalitides)
Traumatic (acute head injury)
Heart causes

Seizures for which an underlying cause cannot be determined after thorough diagnostic evaluation are called idiopathic.

The most common cause of seizure in middle aged dogs (between 1 and 5 years) is idiopathic epilepsy.

Epilepsy is found in all breeds and mixed breeds of dogs. A high incidence of seizure disorders occur in Beagles, Belgian Tervuerens, Boxers, Cocker Spaniels, Collies, Dachshunds, German Shepherd Dogs, Golden Retrievers, Irish Setters, Keeshonds, Labrador Retrievers, Miniature Schnauzers, Poodles, Saint Bernards, and Siberian Huskies.


There are three components of a seizure:

1. Pre-ictal phase or aura -  A period of altered behavior in which certain signs of an impending seizure may be evident, such as restlessness, whining, trembling, salivation, affection, wandering or hiding. These signs may persist from seconds to days in duration and may or may not be apparent to you.

2. Ictal phase. - The ictal phase is the seizure itself. The attack may last a few seconds or a few minutes. During this period all of the muscles of the body contract strongly. Your pet usually falls on his side and appears paralyzed while shaking and kicking or paddling. The head will be drawn backward. Urination, salivation, defecation and even vomiting often occur. The animal will be unaware of his surroundings. If this phase is not over in five minutes the animal is said to be in status epilepticus or prolonged seizure, and must be seen by a veterinarian immediately.

3. Post-ictal phase. - This stage occurs immediately after the seizure. Your pet will appear confused and disoriented and may wander or pace. He may still exhibit salivation and may be unresponsive to you, or he may come to you for comfort. Sometimes temporary blindness occurs. This phase may be short or it may last for days. There is no direct correlation between the severity of the seizure and the duration of the post-ictal phase.


  • Seizures that last longer than 5 minutes
  • Seizures that occur more than twice in a 24 hour time period
  • Seizures that begin before your pet has completely recovered from the previous seizure


  • Do not panic. If your pet is having a seizure, he is unconscious and he is not suffering. Your pet may seem like he is not breathing, but he is.
  • Time the seizure. Actually look at a clock or watch and note the time; although it may seem like forever, it may only be 30 seconds.
  • Keep your pet from hurting himself by moving furniture away from the immediate area. Also protect him from water, stairs, and other sharp objects. You can place a pillow under his head to prevent head trauma.
  • Loud or sharp noises may prolong or worsen the seizure.
  • Note what type of muscular activity or abnormal behavior your pet exhibits during the seizure. Your veterinarian may want you to keep a record of the date and length of time of each seizure.
  • If the seizure lasts more than 5 minutes, call your veterinarian or veterinary emergency clinic immediately.
  • Pets do not swallow their tongues. Do not put your hand in your pet's mouth – you will get bitten. Do not put spoons or any other object into your pet's mouth.
  • Keep children and other pets away from your seizuring animal.
  • Remain by your pet's side; stroke and comfort your animal so when he comes out of the seizure you are there to calm him.


Observe your pet's post-seizure behavior. Do not leave your pet unattended or allow your pet access to the stairs until he is fully recovered. It is ok to offer water if he wishes to drink.  Your pet will be confused and may feel as though he did something wrong. Speak softly and with a soothing voice. Arrange to have your pet seen by your veterinarian as soon as possible after the seizure is over.

If your pet has not fully recovered within 30 minutes, contact your veterinarian or local emergency facility.



Diagnostic tests are often performed after an animal has a seizure to identify underlying diseases that may be causing the seizures. The first step is a complete medical history and physical examination including neurological examination and ophthalmologic (eye) examination.

The next step is to perform routine laboratory testing to evaluate the general health of your pet and to identify potential underlying causes of seizures.

The following routine laboratory tests are usually performed:


1. A complete blood count (CBC or hemogram)
2. A serum biochemical profile to evaluate for low blood sugar, low blood calcium and abnormalities of liver function
3. Urinalysis
4. Fecal examination

The need for additional diagnostic tests is determined based on the results of the medical history, physical examination and initial laboratory tests. These tests may include:

1. Bile acid determinations to evaluate liver function
2. Radiographs (x-rays) of the chest and/or abdomen
3. Ultrasound examination of the abdomen to assess internal organs and identify tumors that may be present
4. Cerebrospinal fluid analysis
5. Brain imaging consisting of either computerized tomography (CT scan) or magnetic resonance imaging (MRI).

Pets that experience a number of seizures over a relatively short period of time may require hospitalization while these tests are performed and the animal is monitored for the occurrence of additional seizures. Pets that have cluster seizures, that is more than two seizures in 24 hours, are often hospitalized until they have had no seizures for a 24 hour period. Intravenous administration of drugs may be necessary to control seizures initially. Supportive care may also include fluid therapy, soft bedding, temperature monitoring and repositioning a recumbent animal every two to four hours.


Optimal treatment of any serious or persistent medical condition depends on establishing the correct diagnosis. Seizures have many potential underlying causes, and the underlying cause should be identified before specific treatment can be recommended. Medication with anti-convulsant drugs will often be recommended for patients with idiopathic epilepsy. Your veterinarian will determine if treatment is warranted, and if so, which specific medication is indicated.

Seizure medication usually controls the seizure disorder but does not eliminate seizures entirely. Identification and specific therapy for seizure disorder in your dog is the best treatment.

Drugs commonly used to treat pets with seizures include:

  • Diazepam (Valium®) is not effective for long-term management of seizure disorders in dogs and cats, however your veterinarian may use diazepam administered intravenously to terminate a seizure in an emergency situation.
  • Phenobarbital (Luminal®)  is the most commonly used anti-convulsant drug. More than 60 percent of dogs with idiopathic epilepsy can have their symptoms controlled using phenobarbital at therapeutic dosages.
  • Potassium bromide often is used in conjunction with phenobarbital when seizures cannot be controlled by phenobarbital alone or when evidence of phenobarbital toxicity is present.

Newer anti-convulsant drugs are now available to help control seizures in our pets. These drugs include, but are not limited to:

  • Felbamate (Felbatol®)
  • Levatiracpam (Keppra®)
  • Zonisamide (Zonegran®)
  • Gabapentin (Neurontin®)


  • Administer all prescribed medications as directed by your veterinarian.
  • Keep a "seizure log" that describes all of your pet's seizure activity including date, length of seizure, activity or behavior during the seizure and length of time until your pet is normal.
  • Maintain a complete record of drug dosages and dates of blood drug tests.
  • See your veterinarian to monitor drug blood concentrations as recommended. Blood phenobarbital concentrations usually are evaluated approximately 14 days after beginning phenobarbital therapy.
  • Blood potassium bromide concentrations usually are evaluated approximately six weeks after beginning potassium bromide therapy.
  • Blood drug tests usually are recommended every six to nine months and whenever seizures occur.









If suspect your dog or cat has a seizure disorder please call Merrick Veterinary Group at 516-379-6200 to schedule your pet for a physical examination, bloodwork, and other diagnostic tests today.


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