Unexplained seizure

My niece, in her mid 30's had a seizure today.  She had two seizures just after her fifth (5th) birthday which the Dr's could not identify a cause.  She was given Phenobarbital for a couple of years, taken off the drug and never had another problem until today.  She is healthy, physically active, normal weight and in good physical condition with no known underlying medical issues.  She has been on vacation for two (2) weeks and said that she was tired and thinks that she is getting a cold.  The seizure occurred at work and she was taken to the hospital and referred to a neurologist.  They did a CT scan but everything was normal.

Any idea of why this would occur or suggestions?

[impish]

It could be an angioma.  They usually dont become symptomatic until someone reaches 30-40.    I had it happen to me at 35.   A cat scan will not see a cavernous angioma because it is lo flow.  Try an mri