What is a seizure?
A seizure is a sudden change in body movement or brain function due to an abnormality in your dog’s brain function. Seizures may vary in duration from a few seconds to those that continue until medical intervention. Seizures also vary in severity from a mild numbness or slight sensory impairment to violent convulsions.

Seizures are categorized as being one of two types. A seizure in which the entire brain is impacted is called a general seizure, tonic-clonic seizure or grand mal seizure. A seizure in which in only a small part of your dog’s brain is impacted is called a focal seizure or a partial seizure. Focal or partial seizures may develop into general seizures.  

What will a seizure look like in my dog?
If your dog has a general seizure, he will exhibit a temporary contraction of all muscles and lose consciousness. During this time, he may drool excessively and urinate or defecate. The general seizure usually doesn’t last for long and is followed by muscle spasms that result in the clamping of the jaw and flailing of the limbs. After a general seizure, your dog may remain motionless for a time before returning to normal. Despite the awful appearance of a general seizure, many dogs will recover fully in just a few hours, although in some cases it will take days. 

The symptoms of a focal seizure are often less obvious depending upon what part of the brain is affected. Symptoms can range from behavioral changes such as sudden aggression or fear, dizziness, disorientation or other odd repetitive behavior such as twitches in the face or limbs.