What Causes Lightheadedness, Dizziness And Numb Arms In A Child?

Ten year old grandson came in from playing outside and said he felt like he was "floating", he couldn't
feel his head", then few minutes later said his arms felt numb, and was nauseated. He was able to walk but said he felt dizzy. What could this be? He is able to walk around. His mom has taken his temp. It's normal.