Overview of Seizure Disorders in Dogs
A seizure or convulsion in a dog is a sudden excessive firing of nerves in the brain. It results in a series of involuntary contractions of the voluntary 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 dog falling on his side, barking, gnashing his teeth, urinating, defecating and paddling his limbs.
Seizures are symptoms of some neurological disorder – they are not in themselves a disease. Some underlying causes include:
- Low blood glucose (sugar)
- Liver disease (called “hepatic encephalopathy”)
- Inflammatory or infectious diseases that affect the nervous system
- Poisons or toxins
- Brain tumor
- Head trauma
- Blood vessel disorders that affect circulation to the brain
- Congenital problems – those present at birth – such as hydrocephalus (“water on the brain”).
Seizures frequently are idiopathic , which means the cause cannot be determined. A diagnosis of seizure disorder does not mean nothing can be done for your pet.
There is no current accurate estimate of the incidence of seizure episodes in dogs. Seizures occur in both males and females with equal frequency, and many pets have one seizure and never have another.
Components of a Seizure
There are three components of a seizure:
- Aura. Certain signs of an impending seizure may be evident, such as restlessness, whining, shaking, salivation, affection, wandering or hiding. These signs may persist from seconds to days in duration and may or may not be apparent to you.
- Ictus. During ictus, the seizure occurs. The attack may last seconds or minutes. Your dog may fall on his side and may look like he is kicking or paddling. He will salivate, lose control of his bladder, and be unaware of his surroundings.
- Postictial stage. This stage occurs immediately after the seizure. Your dog 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. The period may be short or it may last for days.
Warning signs that require emergency veterinary attention:
- Seizures that last longer than 10 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
What to do if your pet has a 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. If possible, place a pillow under his head to prevent head trauma.
- Note what type of muscular activity or abnormal behavior does your pet exhibits during the seizures? 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 dog’s mouth – you may get bit. Do not put spoons or any other object into your pet’s mouth.
- Keep children and other pets away from your seizing 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.
What to Do After a Dog Seizures
- Observe your pet’s post-seizure behavior. Do not allow your pet access to the stairs until he is fully recovered. Offer water if he wishes to drink.
- Be prepared for vocalization and stumbling after the seizure ends. You need to be strong and offer support and comfort to your pet. He will be confused and may feel as though he did something wrong. Speak softly and with a soothing voice.
- If your pet has not fully recovered within 30 minutes, contact your veterinarian or local emergency facility.
Diagnosis of Seizures in Dogs
Diagnostic tests are needed to determine the presence of an underlying disease or cause for the seizure disorder. Seizures for which an underlying cause cannot be determined after thorough diagnostic evaluation are called idiopathic. Tests may include:
- Complete medical history
- Thorough physical exam, including a complete neurologic examination and complete examination of the back of the eyes ( “fundiscopic” examination)
- Blood tests to determine your pet’s general health and the presence of an underlying disease that may be causing the seizures.
- Fecal examination
- Other diagnostic tests as needed based on the results of the history, physical examination and initial laboratory tests.
Treatment of Seizures in Dogs
Results of the history, physical examination and initial laboratory tests will determine the need for further diagnostic tests and will help determine the appropriate treatment for your pet’s seizure disorder. Treatment will be dictated by the underlying cause. When possible, the specific underlying cause of the seizure disorder should be treated.
Home Care of Dogs with Seizures
If your pet has a seizure, call your veterinarian promptly.
During a seizure, concentrate on observing the characteristics of the seizure while keeping him from harm. Do not attempt to open your pet’s mouth or manipulate his tongue – you may get bitten inadvertently. Protect your pet from injury by moving hazardous objects like furniture with sharp corners, or protecting him from falling down stairs. Loud or sharp noises may prolong or worsen the seizure.
After the seizure, give your pet sufficient time to recover from the seizure. Speak calmly and try to comfort your pet. Arrange to have your pet seen by your veterinarian as soon as possible after the seizure is over.
If the seizure episode lasts more than 10 minutes, you should arrange to be seen by your veterinarian or emergency veterinarian as soon as possible.
Prevention is aimed at keeping your pet calm and safe. Avoid exposure to poisons and toxins that can cause seizures – do not allow your pet to roam unsupervised. Keep him in a safe environment for when a seizure does occur. Keep your pet in a fenced yard or on a leash when going for a walk.
Make sure your pet receives all of the appropriate vaccinations so as to prevent known infectious causes of seizures like distemper and rabies.
Information In-depth on Seizures in Dogs
Several different diseases may cause seizures. The term idiopathic epilepsy refers to a seizure disorder that has an unknown cause despite a thorough diagnostic evaluation. Treatment and prognosis (outcome) of seizures depend on their underlying causes.
Common Causes of Seizures in Dogs
The most common causes of seizures in young dogs (less than 1 year) may include:
- Degenerative (storage diseases)
- Developmental (hydrocephalous, porto-systemic shunts)
- Toxic (lead, organophosphates)
- Infectious (distemper or other viral, bacterial and fungal encephalitides)
- Metabolic (transient hypoglycemia, enzyme deficiency)
- Nutritional (common with parasitism)
- Traumatic (acute head injury)
In dogs that are greater than 5 years, the causes may include:
- Neoplasia (either primary or metastatic cancer)
- Metabolic (hepatic or kidney failure)
- Infectious (distemper or other viral, bacterial and fungal encephalitides)
- Traumatic (acute head injury)
- Heart causes
The most common cause of seizure in middle aged dogs (between 1 and 5 years) is idiopathic epilepsy. However, it is commonly recommended that some of the above causes of seizures be ruled out with blood tests and sometimes imaging studies.
Diagnosis In-depth of Seizures in Dogs
Diagnostic tests are performed to identify underlying diseases that may be causing the seizures. Diagnostic tests may include:
Complete medical history and physical examination including neurological examination and ophthalmologic (eye) examination. Routine laboratory tests to evaluate the general health of your pet and to identify potential underlying causes of seizures, including the following:
- A complete blood count (CBC or hemogram)
- A serum biochemical profile to evaluate for low blood sugar, low blood calcium and abnormalities of liver function
- Bile acid determinations to evaluate liver function
- 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:
- X-rays of the abdomen to evaluate liver size
- Ultrasound examination of the abdomen to evaluate liver size, assess other internal organs and identify tumors that may be present
- Electroencephalography (EEG) to record electrical activity of the brain
- X-rays of the skull
- Blood lead determination if lead poisoning is suspected
- Cerebrospinal fluid analysis
Brain imaging consisting of either computerized tomography (CT) or magnetic resonance imaging (MRI). MRI is more sensitive than CT for examining the brain but cost and availability may limit its use.
Your veterinarian may recommend additional diagnostic tests based on the results of initial examinations. These tests may help diagnose other concurrent medical problems or allow your veterinarian to better understand the impact of the underlying disease on your pet. Such tests ensure optimal medical care and are selected on a case-by-case basis.
Treatment In-depth of Dogs with Seizures
Optimal therapy 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 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:
- Phenobarbital is used most commonly to treat seizures in dogs. More than 60 percent of dogs with idiopathic epilepsy can have their symptoms controlled using phenobarbital at therapeutic dosages.
- Primidone is considered more toxic and less effective than phenobarbital.
- Phenytoin is of limited effectiveness and generally is not recommended.
- Potassium bromide can be used alone or is often used in conjunction with phenobarbital when seizures cannot be controlled by phenobarbital alone or when evidence of phenobarbital toxicity is present. Potassium bromide has no effect on the liver.
- Diazepam (Valium®) is not effective for long-term management of seizure disorders in dogs. Your veterinarian may however use diazepam administered intravenously to terminate a seizure in an emergency situation.
- Other drugs used to control seizures include Zonisamide and Levetiracetam. The use of these drugs are becoming more common.
- Drugs used with other drugs to control seizures include Gabapentin, Clorazepate, and Topiramate.
- Pets that experience a number of seizures over a relatively short period of time may require hospitalization while 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 such as diazepam, pentobarbital or propofol may be necessary to control seizures initially. Supportive care may include fluid therapy, soft bedding, temperature monitoring and repositioning a recumbent animal every two to four hours.
Follow-up Care of Dogs with Seizures
- 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.