What caused teen's sudden, constant seizures?

Sarah and Pedro Mendez have kept count: Tuesday marked their 19th straight day at Helen DeVos Children's Hospital.

"I'm not going anywhere, either,” Sarah Mendez told 24 Hour News 8 Tuesday from the lobby of the Grand Rapids hospital. “I mean, my baby's upstairs." (Aug. 15, 2017)

[jeremyphillips]

For anyone else wondering whatever happened to Diego, since these kinds of stories are never followed up on, he was given an experimental drug that seems to be working for him, and after 81 days in the hospital, he was transferred to a recovery center to start rehabilitation. There was no further information after 2017 on the internet, so I'm assuming he's fine now.

[jaredanderson]

For anyone who is wondering it is more than rare it is very rare. Kids of 3-15 have a chance between of 1 and 1, 000, 000. Some kids can become in a vegetation state or worse, have a 30 percent chance of dying. I know this because I have this syndrome or disease
when I was in the hospital I died 3, 4, 5 times but I was lucky enough to have a second chance and I was put into a coma like Diego was. I was also a normal kid myself before all of this happened, I was an athlete, no allergies, just a normal kid. My family went through so much pain seeing me like that. It took 2 months to recover, but never recover from what happened to me. I’ve had this syndrome or disease for 6 years now and they still don’t know what happened to me. The thing that is permanent from this happening are the seizures, I have to have medicine daily now going on my 7th year.

[rooeydonovan]

Did they test for thyroid antibodies just wondering?