Hi. I am new here and have not seen any of your other posts about Bear's seizures, so forgive me if I tell you things you already know....but I have years of experience with big dog seizures, and thought perhaps I could help. My Malamute mix, Samson, was epileptic. He suffered from cluster seizures that were very hard to control...but after doing tons of research I managed to achieve that control, and the dog that so many vets said would never live to age 5 made it 8 1/2 years.
It is quite possible that Bear has epilepsy, if all his lab work is normal. Epilepsy is generally diagnosed when all other causes are ruled out....toxins, traumatic brain injury, tumor, etc. Some animals develop food allergies that lead to seizures, but in my experience this is rare.
The smacking and chomping is a Focal Seizure - one that does not affect the entire body. A Grand Mal seizure involves the whole body - classic posture is the dog on it's side, hind legs drawn tight to the body, front legs out stiff and straight, mouth open wide, all muscles very rigid and the body shaking and quivering. Most dogs do "paddling" with their front paws when they come out of a Grand Mal. Many are blind and confused afterwards, and can remain so for several minutes to several hours. This is called the Post Ictal Phase. Some dogs can be nasty while they are post ictal, so be careful....the y may snap at you or other dogs out of fear.
The longer the seizure, the more damage it causes to the brain. A very long seizure or a cluster of seizures that keep coming with little time in between can lead to Status Epilepticus (constant seizing) which is quite dangerous and can only be controlled with IV meds (Valium, Phenobarbital).
As far as treatment goes: Epilepsy is usually only treated with meds if the dog has more than 1-2 seizures a month, if they have cluster seizures (Samson never had just one...he always had spells that lasted 3 days with 20-45 seizures!). Unfortunately, these big guys with seizures are generally harder to control. Most vets use Phenobarbital as their first line treatment. It is pretty effective, but has alot of side effects....let hargy, weight gain, and liver damage. Any dog on Phenobarb needs to have their liver enzymes tested several times a year. Phenobarb is cheap. Another drug that is VERY good is Potassium Bromide (Kbr). It is one of the best for controlling cluster seizures. It does not cause liver damage (it's processed by the kidneys). You must be very careful about dosage, as it can reach toxic levels. It's main side effect is Ataxia (hind leg weakness). Kbr is a compound drug and the prescription must be filled at a compound pharmacy. It is a bit more expensive, but not bad (cost me about $60-70 a month for Sam, who weighed 110 lbs.)
There is also a Valium Protocol that can be used to control/stop cluster seizures. We used it on Samson for years....if we got to him after the first seizure he wouldn't have any more. Most vets are not familiar with it (I have had to teach several about it when I moved around the country), and it is tough....invol ves a large dose of liquid rectal Valium followed by oral Valium every 4 hours....but it can be a lifesaver.
I don't mean to overload you with information... .but figured this might be my one chance to tell you everything. If Bear's seizures continue and he needs treatment, it will help you to know this stuff. I have tons more information on medications, liver function, the Valium Protocol, etc. Those of us with seizure dogs usually end up knowing much more about canine epilepsy than the average vet. I would be happy to answer any questions you have, point you in the direction of a good vet neurologist if you need one, etc. Please feel free to contact me! lakelynn@starband.net
