Traumatic Brain Injury: All What You Need To Know

Most people sustain some form of an injury at one point or another. Injuries are a part of life, and they are usually manageable with a mild to moderate impact on quality of life. Some injuries are more serious due to scary accidents. Brain injury is one of them. Traumatic brain injury isn’t uncommon, but it can be unpredictable. Not everyone will experience the same symptoms or have the same recovery from a traumatic brain injury. In this post, we’re going to cover traumatic brain injury and everything you need to know about it.

What is traumatic brain injury?

Traumatic brain injury (TBI) is defined as a disruption in the normal function of the brain that can be caused by penetrating head injury or bump, blow, and jolt to the head. Basically, TBI is not a single problem. Instead, it is an umbrella term that refers to different forms of injuries occurring from accidents, trauma, and other causes and disrupting brain function.

In terms of complexity, traumatic brain injuries range from mild to moderate and severe. Mild TBIs affect the brain temporarily, whereas more serious injuries can cause severe symptoms with long-term consequences and complications. In some cases, TBIs are lethal.

How common is traumatic brain injury?

Traumatic brain injury is common, but how prevalent is it? According to some estimates, 69 million people suffer from TBI from all causes each year. The greatest overall burden of disease is observed in Southeast Asian and Western Pacific countries. Head injury after road traffic collision is more prevalent in low- and middle-income countries. The estimated incidence of traumatic brain injury is the highest in high-income countries, specifically Europe and North America.

Of all types of injuries, those to the brain are among the most likely to result in permanent disability or death.

So, how many people in the U.S. experience traumatic brain injury? Some numbers show about 1.5 million Americans sustain TBI each year. About 1,365,000 Americans are treated for TBI and released from the emergency department (ED) every year. Moreover, around 5.3 million people in the U.S. live with TBI-associated disabilities.

It’s also useful to mention that about 75% of people with TBI lose their jobs within 90 days of returning to work if they don’t have proper support.

In the United States, about 80% of all TBI cases are considered mild.

When it comes to the U.S., it’s useful to mention CDC’s report from 2014, which showed about 2.87 million TBI-related emergency department visits, hospitalizations, and deaths occurred that year. The leading cause of TBI was the falls which accounted for 48% of all cases of TBI-related ED visits.

The year 2014 is the last year for which specific statistics regarding TBI were published by CDC.

But together with the average estimates mentioned above, these data paint a clear picture of how common traumatic brain injury really is in this country.

Types of TBI

Not all traumatic brain injuries are the same. We can categorize them into two groups based on the way they occur. These include:

  • Closed brain injury – happens due to a non-penetrating injury to the brain with no fracture in the skull. Rapid forward or backward movement usually causes closed TBI. This type of brain injury can also result from shaking of the brain inside the bony skull leading to bruising and tearing of blood vessels and brain tissue. In most cases, closed brain injuries occur in car accidents, sports, or due to falls. It’s also useful to mention that shaken baby syndrome belongs to this type of TBIs as well.
  • Penetrating brain injury – also known as open brain injury, occurs due to a break in the skull, e.g., when a bullet pierces through the brain.

Below, you can take a look at the most common types of traumatic brain injuries.


A concussion is a traumatic brain injury caused by a blow to the head. The injury affects the function of the brain, and its effects are usually temporary. Some concussions cause loss of consciousness, but most of them do not.

In most cases, concussions are a mild TBI without any gross structural damage. They occur secondary to a non-penetrating or closed TBI.

The human brain has a gelatin-like consistency. The cerebrospinal fluid inside the skull cushions the brain in order to protect it against everyday impacts such as bumps and jolts. That said, a significant blow to the head, neck, or upper body may cause the brain to slide back and forth forcefully against the skull’s inner walls.

Brain injury can also occur due to acceleration or deceleration of the head in events such as violent shaking or a car accident.

Concussion affects brain function, but it’s not a long-term result. It’s useful to mention concussion can cause bleeding in or around the brain.


A contusion is a bruise to the brain. This type of brain injury promotes bleeding and swelling inside the brain, around the area where a person has sustained a blow to the head. Contusion may occur together with blood clots and fracture. In some instances, bleeding in the brain can occur spontaneously.

Not all cases of a contusion are caused by accidents and traumas. For example, older adults may develop contusions due to long-term high blood pressure. Children and adults may have bleeding disorders that may lead to the formation of contusions on the brain. Some illegal drugs and the use of medicines that cause blood thinning may also contribute to this brain injury.

Extra-axial hematoma

The term extra-axial hematoma refers to hematomas present within the intracranial space but outside the substance of the brain. This type of TBI is one of the most common emergencies in neurosurgical practice. Extra-axial hematoma cases almost always result from head trauma.

Extra-axial hematomas include epidural and subdural hematomas. Epidural hematoma (EDH) results from bleeding from the middle meningeal artery and its branches or fracture. In most cases, EDH is acute. On the other hand, subdural hematoma (SDH) happens due to bleeding of a bridging vein. Cases of SDH can be acute or chronic.

Traumatic subarachnoid hemorrhage (SAH)

Traumatic subarachnoid hemorrhage is a common injury. The most common cause of SAH is trauma that leads to the tearing of capillaries with blood, subsequently reaching the subarachnoid space, i.e., space surrounding the brain.

Diffuse axonal injury (DAI)

Diffuse axonal injury is a type of traumatic brain injury that develops when the brain quickly shifts inside the skull as an injury is occurring. As the brain rapidly accelerates and decelerates inside the skull, the long connecting fibers called axons are sheared. This type of TBI can occur in car accidents, violent attacks, sports accidents, but also due to falls and abuse, e.g., shaken baby syndrome.

What are the symptoms of TBI?

Symptoms of traumatic brain injury are numerous. Injury to the brain can manifest itself through both physical and psychological signs and symptoms. Some effects occur immediately after sustaining an injury, whereas others develop days or weeks later.

Not every person will experience the same symptoms. Signs of TBI usually depend on the severity of the injury. Below, you can take a look at symptoms that occur with mild and moderate-to-severe cases of TBI.

Symptoms of mild TBI

We can categorize symptoms of mild TBI into three categories. They are physical, sensory, and cognitive, behavioral, or mental symptoms.

Physical symptoms of mild TBI include:

  • Headache
  • Nausea and/or vomiting
  • Dizziness and impaired balance
  • Speech problems
  • Drowsiness and/or fatigue

Cognitive, behavioral, or mental symptoms of mild TBI include:

  • Difficulty sleeping or sleeping more than usual
  • Losing consciousness for a few seconds up to a few minutes
  • Not losing consciousness, but experiencing the state of being confused, dazed, and disoriented
  • Anxiety and/or depression
  • Mood swings
  • Problems with memory and concentration

Sensory symptoms include sensitivity to light or sound and experiencing problems such as blurred vision, bad taste in the mouth, changes in the sense of smell, and ringing in the ears.

Symptoms of moderate-to-severe TBI

Any of the symptoms of mild TBI can also occur in persons with moderate-to-severe injury to the brain. That said, persons with moderate-to-severe TBI also tend to experience other, more severe symptoms. These symptoms may occur a few hours up to a few days following an injury.

Physical symptoms usually include:

  • Losing consciousness for 30 minutes, but less than 24 hours (in severe cases, the loss of consciousness lasts more than 24 hours)
  • Lack of coordination
  • Headache (persistent and tends to worsen)
  • Weakness/numbness in fingers and toes
  • Persistent nausea and vomiting
  • Inability to wake up from sleep
  • Seizures or convulsions
  • Dilated pupil(s)
  • Drainage of clear fluid from ears or nose

Cognitive or mental symptoms of moderate-to-severe TBI include those of mild traumatic brain injury and profound confusion, slurred speech, coma, agitation, or other forms of unusual behavior.

Causes and risk factors of TBI

As we’ve learned above, traumatic brain injuries usually occur due to a sudden and violent blow to the head. But it’s still useful to sum up all the causes of TBI. The leading causes of brain injuries include:

  • Falls – the most common cause of brain injury, especially in young children and older adults
  • Violence – brain injuries are also a consequence of domestic violence, gunshot wounds, child abuse, and other types of assaults.
  • Vehicle-related collisions – a person may sustain a TBI following an accident involving cars, bicycles, and motorcycles.
  • Sports injuries – active people and athletes may sustain TBI from sports activities, especially in high-impact sports that involve a lot of contacts, such as football, baseball, boxing, hockey, just to name a few.
  • Combat injuries – military personnel is prone to TBIs caused by explosive blasts and other types of trauma that may occur in combat.

Generally speaking, everyone can develop TBI, but some people are more likely than others. The most common risk factors include:

  • Being a male
  • Young age (newborns to 4-year-olds)
  • Young adults (15-24 years old)
  • Older adults (60+ years old)

Diagnosis and treatment of TBI

Experiencing a sudden blow to the head should be followed by a visit to the emergency department where healthcare professionals can assess a patient’s condition. In fact, many cases of TBI are really emergencies, and the risk of complications may increase if a patient doesn’t see the doctor in time. This is particularly the case with severe TBI.

To assess the severity of the injury, a doctor may employ Glasgow Coma Scale, a 15-point test that checks a person’s ability to follow directions, move eyes, limbs, and speak coherently. A doctor may also order imaging tests such as CT and MRI.

In some cases, a doctor may insert a probe through the patient’s skull to monitor intracranial pressure. They do so because tissue from TBI can enhance pressure in the skull and cause further damage to the brain.

Once the severity of TBI has been established, the doctor recommends the most suitable treatment protocol.

Mild TBI usually doesn’t require any treatment. The patient just needs quality rest and OTC pain relievers. That said, the doctor may schedule follow-appointments to assess a patient’s condition again in order to prevent potential complications.

Moderate-to-severe TBI requires emergency care to ensure a patient receives enough oxygen and proper blood supply. The goal is to manage blood pressure and prevent further injury. To limit secondary injury to the brain, a doctor may prescribe anti-seizure drugs, coma-inducing drugs, and diuretics.

Severe injuries may require surgery to minimize further damage to brain tissues. Common surgical procedures include removal of hematomas, skull fracture repairs, and opening a window in the skull.

A patient with serious TBI goes through a rehabilitation process through which they may need to relearn some basic skills such as walking or talking. The main goal of rehabilitation is to improve the abilities to perform daily activities.


Traumatic brain injuries are widely prevalent, especially in North America and other high-income countries. Some cases are mild while others moderate-to-severe. Traumatic brain injuries should be considered emergencies. A patient needs to see a doctor who will assess the severity of the injury and recommend adequate treatment.