Thanks guys. That's really good to know. I guess I jumped to brain tumour because I've known of about 4-5 dogs that have had seizures out of the blue, and all of them ended up having a brain tumour/cancer.
Yes, clear blood work is good, but it also doesn't tell us why...which is hard. It also rules out possible poisoning, diabetes, liver/kidney disease, and infections which can cause seizures.
I also thought she was too old to start having idiopathic seizures? I guess it's possible she had seizures in her first home and they didn't tell the rescue...
She has had 5 seizures in 48 hours varying from 30 seconds to 1.5 minutes. Most have occurred at night. She started seizure meds yesterday, but I assume they will take a little bit to kick in.
Fingers crossed she'll be back to herself soon...