TRAUMATIC BRAIN INJURY (TBI)

This condition can be the result of a jolt to the head or body or a violent blow to the head. Mild traumatic brain injury may affect your neurons microscopically and temporarily although, more serious lesions can result in bruising and bleeding to the brain.

Causes

Traumatic brain injury is usually caused by a blow or other traumatic injury to the head or body. The degree of damage can depend on several factors, including the nature of the injury and the force of impact.

Common events causing traumatic brain injury include the following:

  • Falls. Falls from bed or a ladder, down stairs, in the bath, and other falls are the most common cause of traumatic brain injury overall, particularly in older adults and young children.

  • Vehicle-related collisions. Collisions involving cars, motorcycles or bicycles — and pedestrians involved in such accidents — are a common cause of traumatic brain injury.

  • Violence. Gunshot wounds, domestic violence, child abuse and other assaults are common causes. Shaken baby syndrome is a traumatic brain injury in infants caused by violent shaking.

  • Sports injuries. Traumatic brain injuries may be caused by injuries from a number of sports, including soccer, boxing, football, baseball, lacrosse, skateboarding, hockey, and other high-impact or extreme sports. These are particularly common in youth.

  • Explosive blasts and other combat injuries. Explosive blasts are a common cause of traumatic brain injury in active-duty military personnel. Although how the damage occurs isn't yet well understood, many researchers believe that the pressure wave passing through the brain significantly disrupts brain function.

    Traumatic brain injury also results from penetrating wounds, severe blows to the head with shrapnel or debris, and falls or bodily collisions with objects following a blast.

Risk factors

The people most at risk of traumatic brain injury include:

  • Children, especially newborns to 4-year-olds

  • Young adults, especially those between ages 15 and 24

  • Adults age 60 and older

  • Males in any age group

Complications

Several complications can occur immediately or soon after a traumatic brain injury. Severe injuries increase the risk of a greater number of and more-severe complications.

Altered consciousness

Moderate to severe traumatic brain injury can result in prolonged or permanent changes in a person's state of consciousness, awareness or responsiveness. Different states of consciousness include:

  • Coma. A person in a coma is unconscious, unaware of anything and unable to respond to any stimulus. This results from widespread damage to all parts of the brain. After a few days to a few weeks, a person may emerge from a coma or enter a vegetative state.

  • Vegetative state. Widespread damage to the brain can result in a vegetative state. Although the person is unaware of surroundings, he or she may open his or her eyes, make sounds, respond to reflexes, or move.

    It's possible that a vegetative state can become permanent, but often individuals progress to a minimally conscious state.

  • Minimally conscious state. A minimally conscious state is a condition of severely altered consciousness but with some signs of self-awareness or awareness of one's environment. It is sometimes a transitional state from a coma or vegetative condition to greater recovery.

  • Brain death. When there is no measurable activity in the brain and the brainstem, this is called brain death. In a person who has been declared brain dead, removal of breathing devices will result in cessation of breathing and eventual heart failure. Brain death is considered irreversible.

Physical complications

  • Seizures. Some people with traumatic brain injury will develop seizures. The seizures may occur only in the early stages, or years after the injury. Recurrent seizures are called post-traumatic epilepsy.

  • Fluid buildup in the brain (hydrocephalus). Cerebrospinal fluid may build up in the spaces in the brain (cerebral ventricles) of some people who have had traumatic brain injuries, causing increased pressure and swelling in the brain.

  • Infections. Skull fractures or penetrating wounds can tear the layers of protective tissues (meninges) that surround the brain. This can enable bacteria to enter the brain and cause infections. An infection of the meninges (meningitis) could spread to the rest of the nervous system if not treated.

  • Blood vessel damage. Several small or large blood vessels in the brain may be damaged in a traumatic brain injury. This damage could lead to a stroke, blood clots or other problems.

  • Headaches. Frequent headaches are very common after a traumatic brain injury. They may begin within a week after the injury and could persist for as long as several months.

  • Vertigo. Many people experience vertigo, a condition characterized by dizziness, after a traumatic brain injury.

Sometimes, any or several of these symptoms might linger for a few weeks to a few months after a traumatic brain injury. When a combination of these symptoms lasts for an extended period of time, this is generally referred to as persistent post-concussive symptoms.

Traumatic brain injuries at the base of the skull can cause nerve damage to the nerves that emerge directly from the brain (cranial nerves). Cranial nerve damage may result in: 

  • Paralysis of facial muscles or losing sensation in the face

  • Loss of or altered sense of smell or taste

  • Loss of vision or double vision

  • Swallowing problems

  • Dizziness

  • Ringing in the ear

  • Hearing loss

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What are the symptoms of TBI?

Traumatic brain injury can have wide-ranging physical and psychological effects. Some signs or symptoms may appear immediately after the traumatic event, while others may appear days or weeks later. The signs and symptoms of mild traumatic brain injury may include:

  • Headache

  • Nausea or vomiting

  • Fatigue or drowsiness

  • Problems with speech

  • Dizziness or loss of balance

Sensory symptoms
  • Sensory problems, such as blurred vision, ringing in the ears, a bad taste in the mouth or changes in the ability to smell

  • Sensitivity to light or sound

Cognitive, behavioral or mental symptoms

  • Loss of consciousness for a few seconds to a few minutes

  • No loss of consciousness, but a state of being dazed, confused or disoriented

  • Memory or concentration problems

  • Mood changes or mood swings

  • Feeling depressed or anxious

  • Difficulty sleeping

  • Sleeping more than usual

Moderate to severe traumatic brain injuries

Moderate to severe traumatic brain injuries can include any of the signs and symptoms of mild injury, as well as these symptoms that may appear within the first hours to days after a head injury:

Physical symptoms

  • Loss of consciousness from several minutes to hours

  • Persistent headache or headache that worsens

  • Repeated vomiting or nausea

  • Convulsions or seizures

  • Dilation of one or both pupils of the eyes

  • Clear fluids draining from the nose or ears

  • Inability to awaken from sleep

  • Weakness or numbness in fingers and toes

  • Loss of coordination

Cognitive or mental symptoms

  • Profound confusion

  • Agitation, combativeness or other unusual behavior

  • Slurred speech

  • Coma and other disorders of consciousness

Children's symptoms

Infants and young children with brain injuries might not be able to communicate headaches, sensory problems, confusion and similar symptoms. In a child with traumatic brain injury, you may observe:

  • Change in eating or nursing habits

  • Unusual or easy irritability

  • Persistent crying and inability to be consoled

  • Change in ability to pay attention

  • Change in sleep habits

  • Seizures

  • Sad or depressed mood

  • Drowsiness

  • Loss of interest in favorite toys or activities