Idiopathic Epilepsy In Dogs (Seizures)

Back to Medical Resource Library

Filed Under: Neurology



Seizures are very common in dogs, especially in certain breeds.  The term 'idiopathic' means that there is no identifiable (to the best of our technological capabilities) structural or metabolic cause for the seizures.  Idiopathic epilepsy is also a common disorder in human beings.

Idiopathic epilepsy is the most common cause of seizures in dogs.  Other possible causes include: congenital abnormalities of the brain, such as hydrocephalus or arachnoid cysts; metabolic diseases, such as portosystemic shunts or hypoglycemia; head trauma; brain tumors; and meningitis or encephalitis.  In order to rule in or out the possible causes of a seizure, we may recommend blood tests, radiographs, a brain MRI (less commonly CT) and cerebrospinal fluid analysis if indicated. 
Most dogs with idiopathic epilepsy begin having seizures between 1 and 5 years of age, although this can vary.  There may be a period before the seizure, also called the pre-ictal phase, when the dog becomes very anxious or behaves abnormally.  The seizure episode itself usually only lasts a few minutes.  During a seizure, dogs often fall or lay down on their side.  They may become very rigid or stiff, or they may begin to paddle their legs.  It is common for them to lose control of their bladder and bowels.  Often, a dog may vocalize during a seizure.  During this time, the dog is unconscious and is completely unaware of what is happening.  Once the seizure episode is over, the dog will relax, but there is usually a period of disorientation.  This is called the post-ictal period, and may last for a few minutes, a few hours, or even several days in some cases.  During the post-ictal period, dogs may have difficulty walking, may whine or bark, and may even be temporarily blind.  One of the classic signs of idiopathic epilepsy is that after the seizure and post-ictal period, the dog is normal until the next seizure.

In almost all cases, seizures get worse as time goes on.  This is usually a slow increase in seizure frequency or severity of seizures as the dog gets older.  For this reason, it is generally a good idea to begin anticonvulsant medication early in the seizure disorder. Hopefully, medication will slow the progression of the seizures.

In an ideal world, administering anticonvulsant medication would completely stop the seizures. Realistically, however, this is rarely possible.  The goal of anticonvulsant therapy is to decrease the frequency and severity of seizures as well as increase the duration between seizures, so that the dog may have a good quality of life.  In about 70% of cases, we can achieve this goal with a single medication.

Approximately 50% of dogs with idiopathic epilepsy do not improve with a single anticonvulsant medication.  These dogs are often called 'refractory' epileptics.  They may require a second or even third medication to get better control of their seizures. Rarely, a dog continues to have worsening seizures despite all treatment.

A dog that is receiving anticonvulsant medication requires regular examination and monitoring.  It is especially important to weigh your dog periodically, because any weight gain or loss will affect the dose of medication your dog needs.  Monitoring usually consists of blood tests to check for side effects and to monitor the blood levels of medication.  Monitoring at least every 6 months is essential for any dog on long term seizure medication, even if the seizures are under control.

Almost all anticonvulsant drugs have side effects.  The goal is to get as good control of seizures as possible, with the fewest side effects.  The most common side effects are increased thirst and appetite and increased frequency of urination.  Depending on which drug is prescribed, some dogs may experience drowsiness when they initially begin taking the medication.  Make sure that you know and understand the possible side effects of the medication your dog is taking.  Common anticonvulsant medications used at CVSEC include phenobarbital, levetiracetam (Keppra), zonisamide, and occassionally potassium bromide. 

Please review additional information on our website:

Seizures:  Treatment

Seizures:  Treatment of Resistant Cases