Re: 4 Year-Old Son's First Seizure...Why?
You are pretty much doing EXACTLY what you should do! That's very good seeing how it is making your mind (and emotions) race like crazy (I'd guess).
No there is nothing you can really do until they run the battery of tests and scans to see if it is anything physical or chemical in the body. Sometimes these things just happen when children are growing, or after shots from the doctors, or when they are sick (fevers are a frequent cause for non epileptics).
As one who most likely turned my parents hair gray early when I was 5 (my first seizures lasting an hour!) it was a shocker for the family. There is nothing you can do but keep your eye on the child, don't HOVER (trust me, it was annoying) and see what the doctors say.
As for the head trauma, if the impact was SERIOUS it should show on the MRI... but the child may have verbalized or indicated they were hurting on the head/location (head hurts on the inside? or similar comment). The skull can take a pretty serious impact (trust me!). It's nothing to mess with, but any swelling from the skull is something that I would want looked at.
Be sure to keep notes if you notice anything or the child says anything, behavior changes.