Brain Injury Part II

Let's continue our discussion of brain injury. In Part I, we talked about some functions of the brain, defined some terms that apply to brain injuries, and talked about some common causes of acquired brain injuries. Today we will talk more specifically about TBIs including concussion.

How does the brain get injured in a closed head injury?

It seems obvious how the brain is injured in an open (penetrating) injury, but it may not be so obvious how the brain is injured when nothing penetrates the brain. The brain is enclosed by the skull, which is a very strong bony structure. The cerebrospinal fluid surrounds the brain within the skull. Most of the time, this fluid protects the brain from impact with the skull. However, when there is rapid acceleration or deceleration of the head, the brain may hit the inside of the skull with enough force to cause injury. Rapid rotational movement of the head can also result in damage to the brain.

This bouncing or twisting of the brain inside the skull may cause:

• Blood vessels in the brain to stretch or bleed
• Cranial nerves and brain cells to be damaged
• Tearing or stretching of the connections between brain/nerve cells
• Chemical changes in the brain

What is a concussion?

There are three main types of traumatic brain injury (TBI): mild, moderate, or severe. A mild TBI is also called a concussion. Although they are considered "mild" TBIs, this is because they are usually not life-threatening. It is not because they are not serious injuries. Here are some facts about concussions.

• Concussions should always be taken seriously.
• Concussion is the most common type of TBI.
• Both closed and open head injuries can lead to a concussion.
• An imaging test of the brain, such as a CAT scan is not needed to diagnose a concussion. In fact, concussion may or may not show up on these tests.
• Brain imaging may sometimes be used for patients at risk for bleeding in the brain after mild trauma.
• Falls are the most common cause of concussion. Concussions are also common if you play a contact sport, such as football or soccer.
• Skull fracture, brain bleeding, or swelling may or may not be present.
• A concussion can cause injury that results in temporary or permanent damage.
• It may take a few months to a few years for a concussion to heal. Nerve and brain cells, and the connections between them, take longer to heal than other types of cells in the body.
• Most people usually recover fully after a concussion.
• A person with a history of multiple or repeated mild TBI/concussions may experience longer recovery time, or more severe symptoms. This is especially true if the second concussion happens before the initial concussion has had time to heal.

What are the symptoms of concussion?

Here are some of the common signs and symptoms of a concussion. Keep in mind that a person with concussion may not experience all of these symptoms.

• Brief loss of consciousness immediately after the injury (which would not exceed 20 minutes)
• Feeling or appearing dazed or confused
• Headache or feeling of pressure in the head
• Memory loss surrounding the traumatic event
• Dizziness
• Ringing in the ears
• Nausea or vomiting
• Slurred speech
• Delayed response to questions
• Double vision
• Fatigue

If you or someone you know experiences symptoms of concussion, seek medical attention immediately. Any brain injury needs to be evaluated and treated promptly.

Next week, we will talk about treatment and prevention of TBIs.

If you have any questions about brain injuries, please log into your account and send us your question. We are here to help.

Dr. Anita Bennett MD - Health Tip Content Editor