Updated

Each year, nearly two million Americans are treated for traumatic brain injuries, with 75 percent of those being concussions.

We received this question from a concerned viewer:

Q: I think my son might have a concussion. What are the signs?

A: Concussions are usually caused by a blow to the head, but they can also occur when the head and upper body are violently shaken.

The symptoms may be subtle and are not always immediately noticeable, so it’s important to watch your son closely because concussions can alter brain function.

But here are some signs to look out for:

-- Headache or a feeling of pressure in the head

-- Irritability and concentration issues

-- Confusion or dizziness

-- Ringing in the ears

-- Sensitivity to light and sound

-- Nausea or vomiting

-- Slurred speech

-- Fatigue

You should always take your child to see a doctor after a head injury – even if emergency treatment is not needed. Remember, it’s better to be safe than sorry!

Do you have a health question? Send it to drmanny@foxnews.com