Hyperventilating

Not a real seizure.

I've seen people have syncopal episodes from hyperventilating but not a seizure.

Plus, it would be very difficult to prove that the hyperventilating actually caused/triggered the seizure.

Sometimes syncopal episodes are accompanied by jerking extremities that might look like a brief seizure.

has anyone seen seizures triggered by hyperventilating

Yes, absence seizures. We have kids hyperventilate (little ones are asked to blow on a pinwheel) while having an EEG and this will trigger some kids to have documented EEG changes with a sudden behavioral arrest. It is usually brief (approximately 15 seconds) and the patient returns to baseline immediately after the event.

This is a type of epilepsy and is treated with medication.

As one of the other posters mentioned, there are also those who have convulsive syncope which is not classified as a seizure and not treated with seizure meds. Patient hyperventilate, faint from lack of oxygen to the brain and have a provoked seizure, but it would not be an epileptic seizure. No EEG changes would be seen.

Young children have breath holding spells that also cause them to have seizures, but again, these are provoked, not epileptic (no EEG changes) and are not treated with antiepileptics.