What Is a Traumatic Brain Injury? Understanding the 3 Types

TBIs caused around 2.5 million visits to the ER in 2014.

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Emergency rooms in the United States saw about 2.5 million visits related to traumatic brain injuries (TBIs) in 2014, according to the Centers for Disease Control and Prevention (CDC). The most common cause of TBIs that led to emergency department visits, by far, was unintentional falls.

“A traumatic brain injury is an injury that occurs to the brain,” says Steven Flanagan, MD, chair of the Department of Rehabilitation Medicine at NYU Langone Health. “Think of the brain as a very soft organ. It actually has the consistency of formed Jello [and] it floats in fluid inside your skull.”

“You can imagine the brain kind of squeezes on itself when the body or the head gets hit, and it stretches, and they twist a little bit, and it's that twisting and stretching, particularly of the nerve cells, that results in a brain injury,” says Dr. Flanagan.

However, the millions of emergency room visits for TBI look very different from case to case. There’s a wide range in severity of TBI, resulting in different symptoms, treatment, and prognoses.

Mild TBIs (Concussions)

A mild TBI is more commonly known as a concussion. Someone with a concussion might experience symptoms like:

  • Headache

  • Confusion

  • Dizziness

  • Blurred vision

  • Ringing in ears (tinnitus)

  • Fatigue

  • Memory problems

  • And possible loss of consciousness.

Learn more about symptoms of a concussion here.

About 75 percent of TBIs in the U.S. are—thankfully—categorized as mild, according to the CDC. These can usually be treated with rest and time. (However, it’s still recommended to contact or visit a healthcare provider to ensure there is no risk of bleeding.)

Moderate and Severe TBIs

“When we think [of] severe traumatic brain injury, we're thinking [about] folks who've had a lot of force applied to the brain,” says Dr. Flanagan. “There's swelling inside of the brain. There may be bleeding.”

Someone with a moderate or severe TBI may have the same symptoms as someone with a mild TBI, but they may also have additional symptoms, according to the National Institute of Neurological Disorders and Stroke. Warning signs of a moderate or severe TBI include:

  • Headache that gets worse or won’t go away

  • Nausea and vomiting

  • Seizures

  • Dilation of one or both pupils

  • Slurred speech

  • Inability to wake up from sleep

  • Numbness in the hands or feet

  • And reduced coordination.

A moderate or severe TBI requires immediate medical attention due to the risk of brain damage and complications, such as ruptured blood vessels (hematomas) or bruised brain tissue (contusions).

“When in doubt, seek out help, whether it's an emergency room, or you call your healthcare provider,” says Dr. Flanagan. “Seeking out good care, getting answers to your questions early, is actually a good way to help speed up the recovery.”