Summary from article at http://dogs.about.com/od/caninediseases/p/seizures.htm?nl=1

By Jenna Stregowski, RVT

A seizure is caused by an abnormal neurological activity in the brain which causes all sorts of reactions including but not limiting to convulsions, shivers, twitching, snapping etc. They can be caused by a myriad of things and may last anywhere from a few seconds to hours in some extreme cases. They can generally be classified as focal or general.

Generalized Seizures

These are the ones that most commonly affect dogs. These kinds of seizures affect the whole body and commonly include convulsions, tremors, and other involuntary movements. Some dogs may void their bladder/bowel and in some cases they may make sounds (a seizure in which a dog makes vocalizations is called a tonic seizure).

Focal Seizures

These kinds of seizures involve neurological activity including only a specific part of the brain and therefore only affects certain parts of the body. They can be mild and include facial twitching, limb twitching, etc. There are cases when these seizures may look like a fainting spell or a brief period of disorientation, at others a dog may do something called 'flybiting' in which they randomly snap at the air.

Cluster Seizures

A cluster seizure is when a dog has more than one seizure in a period of 24 hours. These tend to be more grave and in greater need of medical attention. If a dog has more than 3 seizures within a 24 hour period it is considered an emergency in which a dog must see a vet that same day. Not taking the appropriate measures to get the dog to see medical help can worsen the severity and increase the frequency of the seizures.

Status Epilepticus

This is when a dog has a continued seizured for a long period of time or consecutive seizures with small intervals. It is urgent to get a dog in status epilepticus to a hospital otherwise the dog can suffer from brain damage, hyperthermia, or even death.

Phases of a Seizure

There are three stages of a seizure, pre-ictal, ictus, and post-ictal.

Not all dogs go through the first stage, which happens right before a seizure. The pre-ictal stage can sometime be characterized by whinning, pacing or panting.

The actual seizure is called the Ictal stage or Ictus.

Almost all dogs will go through the last stage which would be the post-ictal stage. This usually includes stupor, disorientation or blindness and may last anywhere from a few minutes to hours.

Causes

Because seizures can be caused by many things your vet may recommend to do several tests/scans to see what the problem might be. Some of the following are often causes of seizures:

-Structural Abnormality
-Negative reaction to a poison or allergen
-Systematic disorders
-Infections
-Tumors in the brain

For more information about managing a dog during a seizure please visit the link above.

very interesting information. I have never had a dog has has *yet* had a seizure but they can be pretty scary i can imagine since ive seen people have them. good info to know abuot different kinds.

This type of seizure may be either "Mild" or "Grand Mal" (severe). In the "Tonic" phase of this seizure, a dog typically loses its balance and immediately extends its limbs. This usually continues for roughly 20-30 seconds before the next phase (the "Clonic" phase) begins. In the Clonic Phase, a dog will begin a "running in place" motion, which may be combined with contraction of the jaw muscles.

How can seizure be prevented? Can a dog get seizure every time the weather is so hot? Is seizure related to epilepsy?

AnnSmith wrote:

How can seizure be prevented? Can a dog get seizure every time the weather is so hot? Is seizure related to epilepsy?

They can be prevented with medications. Ummm I'm not sure if extreme weather can cause seisures although it might be possible. And yes usually seisures are related to epilepsy but not always.