Seizures in Dogs
Seizures are the most common neurological disorder encountered in dogs. They can be extremely distressing to the pet owner and to the pet. Seizures indicate a disturbance in the front part of the brain (the forebrain or prosencephalon). It is the physical manifestation of excessive and hypersynchronous electrical activity in the forebrain.
Classification and Diagnostic Approach
Seizures can be classified as:
- Extracranial or Metabolic: These are caused by problems outside of the brain that secondarily affect the brain. Examples of extracranial or metabolic causes of seizures include low blood sugar, toxins, severe liver disease and others.
- Intracranial or Structural: These are caused by problems directly involving the brain. Examples of intracranial or structural causes of seizures include brain tumors, head trauma, encephalitis, strokes and others.
- Idiopathic Epilepsy: These are recurrent seizures that are not caused by any extracranial or intracranial cause. There are a few generalizations that can be made about idiopathic epilepsy– most dogs are between 1-5 years of age when they have their first seizure. They act normally between seizures and have normal neurological examinations. There is often a ‘regular’ pattern or frequency to the seizures.
One of the most important steps in determining the cause of seizures is a thorough neurological examination. A reasonable list of possible causes can be made based on signalment (the pet’s age and breed), history, and neurological examination. Diagnostics (tests) are typically necessary to determine the cause of seizures. Extracranial (or metabolic) causes are often diagnosed with blood tests. Intracranial (or structural) causes of seizures require an MRI and possibly a CSF analysis to determine the cause. CT scans and low-field MRI can miss many of the causes of seizures. Idiopathic epilepsy is diagnosed by ruling out metabolic and structural causes of seizures (i.e. with normal blood work, x-rays, MRI and CSF analysis).
Treatment of seizures depends on identifying the underlying cause of seizures. For example, the treatment for seizures due to low blood sugar is very different than treatment for seizures due to a brain tumor. Accurately determining the cause of the seizures is important in optimally treating the seizures. Anti-epileptic drugs are often prescribed for treatment of seizures. For many causes of seizures (including idiopathic epilepsy), the goal of therapy is to decrease the frequency, severity and duration of seizures. Some of the medications used to treat seizures in dogs include:
- Potassium bromide
- Levetiracetam (Keppra)