We know that a hard blow to the head can cause a concussion. A class action on behalf of 4,500 ex-NFL players brought this issue to mainstream attention when they asserted the NFL knew of the high concussion risk in the sport, and the devastating effects, but didn’t take appropriate action. The NFL now faces a $1 billion settlement.

But did you know you can sustain a concussion even without a hard hit to the head? Sudden jolts, such as what happens in a car accident, can cause brain injury.

Why? Your brain floats in cerebral fluid that protects it from jolts and bumps. When you fall and hit the ground, when a linebacker tackles you, or when you get rear-ended on a busy road, the brain sloshes around and hits the skull. This can result in torn nerve fibers and ruptured blood vessels, both of which affect brain function.

The immediate symptoms of concussion can include:

Loss of consciousness

Confusion

Headache

Slurred speech

Dizziness

Ringing in the ears

Nausea

Vomiting

Amnesia

Tiredness

Doctors often have a difficult time diagnosing concussion, because some symptoms don’t show up for a few days or weeks after impact. Delayed symptoms can include:

Amnesia

Depression

Disturbed sleep

Sensitivity to sounds

Irritability

Lack of concentration, focus

Moodiness

Sensitivity to light

Concussion symptoms are even trickier to diagnose in young children, because kids can’t explain how they feel. If your child sustains anything more than a light bump or jolt, look for the following symptoms:

Lethargy, listlessness

Irritability

Changing sleeping patterns

Altered appetite

Walking and/or standing unsteadily (any signs of dizziness or balance problems)

If you sustained a head injury from a car crash, fall, or some other incident, visit your doctor right away. Some concussions cause internal bleeding, which can be fatal if left untreated.

Often concussion symptoms clear up on their own. To manage concussion, it’s important to rest. Get a good night’s sleep. Don’t take on stressful tasks, such as work or reading complex material, for as long as your doctor recommends. Let your brain recover. And don’t drink alcohol while you’re recovering, because it slows healing.

Traumatic brain injury (TBI) contributes to about 30 percent of all injury-related deaths according to Centers for Disease Control and Prevention (CDC). Motor vehicle crashes were the third overall leading cause of TBI-related emergency room visits, hospitalizations, and deaths (14 percent).

Don’t rule out concussion just because you didn’t hit your head or lose consciousness. Concussions are not immediately obvious, but immediate treatment can make a big difference in your recovery.

If you’ve suffered a head injury in an auto, bicycle, or pedestrian accident, contact a personal injury lawyer as soon as you are able. Most lawyers will give you a free consultation to review your case and help you understand your rights.