Hello, my name is***** and I have over 20 years of experience as a veterinarian. I'm sorry to hear that Dexter has had a few possible seizure episodes and I understand your concern for him.
Seizures are rhythmic, repetitive, muscle movements which the dog is unable to control and often loses consciousness during. Many dogs will repeatedly have chewing motions and/or leg motions and can lose urine and stool control. In some cases like your fellow the seizure may be more subtle and they may just become very tense and unable to respond.
There can be several reasons for seizures.
The most common is idiopathic epilepsy. That means that we don't know why but a circuit of sensitive neurons in the brain gets stuck repeatedly firing. Epilepsy occurs most frequently for the first time in dogs 6 months to 6 years of age so he is in the right age range for this to be the cause of his seizures. We do believe that there is a genetic basis for dogs to have epilepsy as certain breeds are more commonly afflicted and siblings will often have them as well. If mom carried some of the genetics for epilepsy she may not be affected. But if she bred with a male that also carried some of the genetics for epilepsy (and he may not have been affected either) then together if the wrong combination of genes resulted we could get puppies with epilepsy.
Other causes for seizures are viral, bacterial, parasitic or fungal infections, metabolic diseases leading to waste products building up and affecting brain chemistry, low blood sugar, or even granulomas or masses in the brain.
Most of the other disease processes that cause seizures cause other symptoms, those dogs are sick or abnormal other than during the seizure.
Some dogs with lower than normal seizure thresholds will seizure in response to being exposed to artificial colors, preservatives or gluten. So you might wish to feed him a diet without artificial dyes or flavors and one that is wheat free. Blue Buffalo purports to produce these sorts of foods.
Decreasing stress is also a way to avoid seizures so if you know an event will be stressful for him avoid it if possible. You can also use calming sprays such as DAP (dog appeasing pheromone) or pheromone impregnated collars to keep him calm.
Exercise should be kept at normal levels. Exercise is a great way to naturally relieve stress and increase positive endorphin levels in the brain.
In a patient with seizures I would have your veterinarian examine him, check a biochemistry profile to look at organ health and a complete blood count. We do want to make sure there are no underlying problems.
If his seizures become more frequent than once a month or more than one happens in a day, even if it has been several months since the last one, I would discuss medication to prevent them. The reason for that is the likelihood of status epilepticus (one seizure after another) and possible brain damage is higher with those scenarios and we wish to avoid that.
At this point if he seems his happy self otherwise I would just plan on having him rechecked by his veterinarian this week for basic blood tests and discussing possibly starting medication.
Please let me know if you have any further questions.