T.,
My 6-year-old nephew used to have them when he was a baby. He was in the hospital frequently. My brother-in-law and his wife had their son tested and did whatever the doctor told them to do. He stopped having them after a while. It didn't last more than a year. I don't know if that means he out-grew it, but I do know that he's okay now. They said it was scary to watch, but it didn't do any permanent damage. He's a very smart, very healthy little boy now. So hang in there.
When my son was 9 months old he had a UTI. His temp was up to 103. He was sleeping at the time, but I heard him make a strange cry and when I checked on him he was shivering, but burning up. His eyes were rolling in his head and he made this moaning sound. His body went limp after a while. It was the most terrifying thing ever. I called 911 and they checked him out. Someone suggested that it could have been a seizure, but I didn't witness it, so we don't know. The high fever was caused by the UTI.
Every doctor I spoke to that night said that seizures of that nature don't cause permanent brain damage. It's just important to get the temp down. They gave him a dose of Tylenol and Motrin at the same time to bring his temp down quickly. I'm blessed that he's never had an experience like that again. You should just be prepared with medication for his temperature and an emergency contact number for your ped at all times. They told me to keep him in only a diaper while waiting for his temp to go down. The 30-second ear thermometer is helpful too. I checked my son's temp every time he felt warm after that experience. He doesn't even notice anymore!
Good luck.
-T.