An insult to the brain, not degenerative or congenital in nature, but caused by an external, mechanical force, which may cause a diminished or altered state of consciousness. Thus, it is NOT caused by something internal such as a stroke or a tumor. Even though brain injury is oftentimes associated with a single event, it should be viewed as a chronic disease process. The cognitive, physical and emotional impairments that may result from head trauma depend on the areas of the brain that are injured. Symptoms may appear immediately or they may not occur for days or weeks after the injury. It is important to note that no two brain injuries are alike and even two similar injuries may present very different symptoms/ effects.
TBI can be classified according to three levels of severity:
1. mild
2. moderate
3. severe.
Mild traumatic brain injury (MTBI)
MTBI can be classified as a traumatically induced physiological disruption of brain function, with at least one of the following:
Concussion (on the low spectrum of TBI)
Definition: complex pathophysiological process affecting the brain, induced by traumatic forces:
Pathophysiology associated with sport concussion:
Symptoms:
Moderate traumatic brain injury
It involves trauma to the head that results in:
Severe traumatic brain injury
A severe TBI is associated with the following:
TBI can be classified according to three levels of severity:
1. mild
2. moderate
3. severe.
Mild traumatic brain injury (MTBI)
MTBI can be classified as a traumatically induced physiological disruption of brain function, with at least one of the following:
- any loss of consciousness (LOC)
- any memory loss, before or after the event
- any alteration of mental state, including disorientation and confusion
- focal neurological deficits that may or may not be temporary
- LOC for longer than 30 minutes.
- Glascow-Coma Scale score (see Diagnosis tab) of 13-15 after 30 minutes
- post-traumatic amnesia (PTA) that lasts longer than 24 hours.
Concussion (on the low spectrum of TBI)
Definition: complex pathophysiological process affecting the brain, induced by traumatic forces:
- direct blow to body/ impulsive force transferred to the head
- rapid onset, short lived neuroimpairment that resolves spontaneously
- recovery follows a sequential course
- may not involve LOC
- typically normal imaging on CT/MRI
Pathophysiology associated with sport concussion:
- stretching of an axon results in multilayered neurometabolic cascade of cellular and vascular changes
- ionic shifts
- abnormal energy metabolism
- diminished cerebral blood flow
- impaired neurotransmission
Symptoms:
- Nausea and vomiting
- Blurred vision
- Confusion
- Short-term memory loss
- Fatigue (major symptom)
Moderate traumatic brain injury
It involves trauma to the head that results in:
- LOC of 30 minutes to 24 hours
- an initial Glasgow Coma Scale of 9-12
- PTA can last 24 hours to seven days.
Severe traumatic brain injury
A severe TBI is associated with the following:
- LOC of greater than 24 hours
- an initial Glasgow Coma Scale of 3 - 8
- PTA for longer than 7 days.