What Causes Pain In Ankle Radiating To Back After An Injury?

My husband twisted his ankle, as soon as he realized he stopped in his track and couldn't move. His mother brought him to sit down and he immediately blacked out for about a minute. When he came to, he said he couldn't hear or see anything for a couple minutes. And when it happened, he said he felt the pain from his ankle shoot up his back, and now suddenly he is really, really sleepy. Should we go to the Doctor?