Let’s learn about traumatic injury to the central nervous system.
The central nervous system consists of the brain and spinal cord.
Trauma to the brain or spinal cord can occur from forces that exceed the protective mechanism
of these structures.
Examples include sports injuries, automobile accidents, falls, assault, and shaken baby
syndrome.
A traumatic injury to the brain is called a concussion or TBI (traumatic brain injury).
2 types of traumatic brain injury include closed brain injury and penetrating brain
injury.
There is no break in the bones of the skull in a closed brain injury.
Forces to the skull such as violent movements result in damage to brain tissue and blood
vessels.
Forces resulting in a break in the skull can cause a penetrating brain injury.
Examples include objects that penetrate the skull such as debris from an accident or bullets.
Diffuse axonal injury occurs when shearing or twisting forces cause damage to the axon
portion of neurons.
Diffuse axonal injury is characterized by a loss of consciousness that lasts for several
hours and resulting brain damage symptoms that include:
disorientation or confusion headache
nausea or vomiting drowsiness or fatigue
trouble sleeping sleeping longer than normal
loss of balance or dizziness Traumatic brain injury can be classified as
mild, moderate, or severe.
This classification is based on the Glasgow coma scale.
The GCS uses a scoring system where points are given for eye opening responses, verbal
responses and motor responses.
Points are given for specific function in each area in order to determine an overall
score.
The Glasgow coma scale includes 5 levels functioning.
These are 1: Death.
Severe injury or death without recovery of consciousness
2.
Persistent vegetative state Severe damage with prolonged state of unresponsiveness and
a lack of higher mental functions 3.
Severe disability Severe injury with permanent need for help with daily living
4.
Moderate disability.
No need for assistance in everyday life, employment is possible but may require special equipment.
5.
Low disability.
Light damage with minor neurological and psychological deficits.
There is also an Expanded Glasgow coma scale that includes additional states of functioning
by subdividing the upper three categories.
.
Traumatic spinal cord injuries occur mostly in young male adults with auto accidents and
violent events as the leading causes.
The most common spinal cord injuries occur at C5-C7, T12, and L1 and the Injury often
extends 2 segments above and below the site of damage.
The damage may include hemorrhage in the spinal cord gray matter and meninges that can lead
to necrosis.
Hemorrhage to the white matter of the spinal cord can lead to damage from ischemia.
Macrophages respond to damage by ingesting axons and damaged meningeal tissue by way
of phagocytosis.
These tissues are then replaced by non-functioning connective tissue that further alters spinal
cord function.
Signs of spinal cord injury range from paresthesias (abnormal sensations such as burning, tingling,
numbness) to paralysis.
There can also be loss of reflexes and autonomic dysfunction including blood pressure changes
and alterations in heart rate, sweating and breathing.
An ischemic injury occurs from inadequate supply of oxygenated blood to the brain or
spinal cord.
Ischemia to the brain can be focal or localized to a specific area or global which involves
larger areas.
Ischemic injuries can occur from occlusion of blood supply including thrombosis, embolism,
or hemorrhage.
Global ischemia can occur from hemorrhage or cardiac arrest while spinal ischemia usually
occurs from occlusion of blood vessels from emboli.
Ischemia injuries to the brain will manifest on the contralateral (opposite) side of the
body.
Signs of ischemic injuries include paresthesias, Loss of consciousness, weakness, difficulty
speaking or swallowing, and impaired vision.
I hope you have learned something about traumatic central nervous system injuries, and, see
you next time.