Concussions Flashcards
What is a Concussion?
Biomechanically induced transient disturbance of neurological function.
Can be associated with a loss of consciousness, temporary loss of brain function, physical, cognitive, and emotional symptoms.
Concussions are also referred to as what?
Mild Traumatic Brain Injuries.
What causes a concussion?
Rapid acceleration/deceleration of the brain.
Brain collides with the skull: front/back or side/side.
Bruising and swelling of brain tissue follows and may persist for up to 48 hours (brain contusion and cerebral edema; increased intracranial pressure).
Impact can be direct or indirect/linear, rotational, or angular.
Does direction of force matter?
Yes.
What does direction of force dictate?
Presenting symptoms, long-term consequences, extent of damage, and rate of recovery.
It makes it difficult to compare concussions between patients.
What does the magnitude of rotational force dictate?
Concussion severity.
What is Diffuse Axonal Injury?
Shearing forces that cause axons to detach from the cell body.
Damaged axons will display indiscriminate release of the GLUTAMATE excitatory neurotransmitter.
Excitotoxic lesions subsequently occur from 24-48 hours post injury.
Which parts of the brain are most affected by rotational forces?
Midbrain and Diencephalon.
Disruption of normal cellular activities is thought to produce what?
Level of Consciousness.
Also damages frontal and temporal lobes.
What is a Subdural Hematoma?
It is a collection of clotted blood and accompanying increased pressure on the brain.
What causes a Subdural Hematoma?
Unrestricted movement of the head results in axon shearing, which leads to a subdural hematoma.
What is an Epidural Hematoma?
It results from the collection of blood between the dura mater and the skull.
What is Chronic Traumatic Encephalophagy?
Result of multiple, sub-concussive blows to the head.
Not a concussion issue.
It is a progressive degenerative disease found in individuals with repeated head trauma.
Characterized by neurofibrillary tangles, plaques, and neuronal death.
What is Second Impact Syndrome?
Occurs when an individual suffers a concussion while still symptomatic from a previous concussion.
Prior concussions increase the likelihood of a 2nd concussion and cause greater morbidity in both human and animal models.
Repeated concussions have a cumulative effect on the human brain.
What are the mortality and morbidity rates of Second Impact Syndrome?
50% mortality rate and 100% morbidity rate.
What are the 3 methods of detection and diagnosis for Concussions?
Immediate Post Concussion and Cognitive Testing (ImPACT).
MRI
EEG
What is ImPACT?
Computer-based battery of tests aimed at detecting post-concussive symptoms.
Demographic questionnaire.
Symptom Inventory.
Injury Evaluation.
20-Minute Neurocognitive Test.
What is an MRI?
Allows us to visualize internal structures.
What is an EEG?
Allows us to record electrical activity.
What are the clinical symptoms of a concussion?
Headache, pressure - Vascular injuries
Temporary loss of consciousness - Brain Stem
Confusion - Corpus Collosum
Amnesia surrounding the event - Hippocampus, Frontal Lobes.
Ringing in the ears - Temporal Lobes.
Nausea and/or vomiting - Area Postrema
Changes in Mood and Emotional Disturbances - Amygdala
What do symptoms of a concussion depend on?
Location of structural damage.
What is BBB Permeability (Secondary Injury)?
Anaerobic glucose metabolism (glycolysis) involves production of lactate - lactic acid.
Overproduction of lactic acid results in acidosis and damage to the Blood Brain Barrier (BBB).
BBB permeability ensues, leaving organism vulnerable to external toxins.
What are Secondary Injuries?
Patient’s condition may deteriorate in stages, which suggests that brain injuries result in various waves of potential damage (primary vs. secondary effects).
Secondary effects may take days, weeks, or months to develop.
Can persist for weeks, months, and even years.
A concussion can lead to what kind of tissue damage?
Neural and vascular - which leads to a distortion of cell membranes (neurone activity picks up and cerebral blood flow is interrupted).
