My 17 Yr Old Grandson Had A Sudden Onset Of

My 17 yr old grandson had a sudden onset of disorientation, confusion, disconnect from reality. He was not taken to ER until 1-2 days later once he got home from a class trip. An ER doctor said it could be a case of emotional stress. His potassium level was higher than normal (don't know #'s). Is it possible he had a stroke and should have had a brain scan?