Excerpt from Traumatic Brain Injury: Definition, Epidemiology, Pathophysiology

Synonyms, Key Words, and Related Terms: traumatic brain injury, head injury, brain injury, head trauma, brain concussion, brain contusion, subdural hematoma, epidural hematoma, skull fractures, subarachnoid hemorrhage, intracerebral hemorrhage

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Definition

Traumatic brain injury (TBI) is a nondegenerative, noncongenital insult to the brain from an external mechanical force, possibly leading to permanent or temporary impairments of cognitive, physical, and psychosocial functions with an associated diminished or altered state of consciousness.

The definition of TBI has not been consistent and tends to vary according to specialties and circumstances. Often, the term brain injury is used synonymously with head injury, which may not be associated with neurological deficits. The definition also has been problematic with variations in inclusion criteria.

For excellent patient education resources, visit eMedicine's Back, Ribs, Neck, and Head Center. Also, see eMedicine's patient education article Concussion.

Glasgow Coma Scale

The Glasgow Coma Scale (GCS) defines severity of TBI within 48 hours of injury.

Eye opening

Spontaneous = 4
To speech = 3
To painful stimulation = 2
No response = 1

Motor response

Follows commands = 6
Makes localizing movements to pain = 5
Makes withdrawal movements to pain = 4
Flexor (decorticate) posturing to pain = 3
Extensor (decerebrate) posturing to pain = 2
No response = 1

Verbal response

Oriented to person, place, and date = 5
Converses but is disoriented = 4
Says inappropriate words = 3
Says incomprehensible sounds = 2
No response = 1

The severity of TBI according to the GCS score (within 48 h) is as follows:

Severe TBI = 1-8
Moderate TBI = 9-12
Mild TBI = 13-15

Ranchos Los Amigos Scale of Cognitive Functioning

The severity of deficit in cognitive functioning can be defined by the Ranchos Los Amigos Scale.

Level I = No response
Level II = Generalized response
Level III = Localized response
Level IV = Confused-agitated
Level V = Confused-inappropriate
Level VI = Confused-appropriate
Level VII = Automatic-appropriate
Level VIII = Purposeful-appropriate

TBI defined by the Head Injury Interdisciplinary Special Interest Group of the American Congress of Rehabilitation Medicine

The Head Injury Interdisciplinary Special Interest Group of the American Congress of Rehabilitation Medicine defines mild head injury as "a traumatically induced physiologic disruption of brain function, as manifested by one of the following:

Any period of loss of consciousness (LOC),
Any loss of memory for events immediately before or after the accident,
Any alteration in mental state at the time of the accident,
Focal neurologic deficits, which may or may not be transient."

The other criteria for defining mild TBI include the following:

GCS score greater than 12
No abnormalities on CT scan
No operative lesions
Length of hospital stay less than 48 hours

The following criteria define moderate TBI:

Length of stay of at least 48 hours
GCS score of 9-12 or higher
Operative intracranial lesion
Abnormal CT scan findings

The National Institute of Health Traumatic Coma Data Bank

The National Institute of Health (NIH) sponsored the Traumatic Coma Data Bank (TCDB). The TCDB reveals that severe TBI is indicated when the GCS score is below 9 within 48 hours of the injury.

Please click here to view the full topic text: Traumatic Brain Injury: Definition, Epidemiology, Pathophysiology

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