Overview
Definition
Traumatic brain injury (TBI) is a nondegenerative, noncongenital insult to the brain from an external mechanical force, possibly leading to permanent or temporary impairment 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 neurologic deficits. The definition also has been problematic with variations in inclusion criteria.
See Posttraumatic Stress Disorder (PTSD), a Critical Images slideshow, to help recognize the symptoms of PTSD and to determine effective treatment options.
For patient education information, see the article Concussion.
Glasgow Coma Scale
The Glasgow Coma Scale (GCS) defines the severity of a TBI within 48 hours of injury.
Eye opening
See the list below:
Spontaneous = 4
To speech = 3
To painful stimulation = 2
No response = 1
Motor response
See the list below:
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
See the list below:
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 = 3-8
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 computed tomography (CT) scan
No operative lesions
Length of hospital stay less than 48 hours
The following criteria define moderate TBI:
Length of stay at least 48 hours
GCS score of 9-12 or higher
Operative intracranial lesion
Abnormal CT scan findings
The National Institutes of Health Traumatic Coma Data Bank
The National Institutes of Health (NIH) sponsored the Traumatic Coma Data Bank (TCDB).
The TCDB revealed that severe TBI is indicated when the GCS score is below 9 within 48 hours of the injury.
Simplified Motor Score (SMS)
The SMS is a 3-point scale developed to address the perceived limitations of the GCS, such as its complexity and poor interrater reliability. The points are as follows:
Obeys commands = 2 points
Localizes pain = 1 point
Withdraws to pain or worse = 0 points
A study by Thompson et al determined that in an out-of-hospital setting, the SMS was similar to the GCS score for predicting TBI outcomes.
Related Medscape Drugs & Diseases topics:
Classification and Complications of Traumatic Brain Injury
Neurointensive Care for Traumatic Brain Injury in Children
See Medscape’s Resource Center Trauma for further information.