Definition/explanation of CNS Trauma:
- A leading cause of death and long term disability in Western society.
- Survivors of head injury
20% severe long term disability
5% permernant vegetable state
¼ of all accident death
Severity and site of injury affect the outcome: injury of several cubic centimeters of brain parenchyma may be clinically silent (if in the frontal lobe), severely disabling (spinal cord), or fatal (involving the brain stem).
Causes of CNS trauma:
- Blunt trauma
- Penetrating missile wounds
Risk factors of CNS trauma:
- Alcohol abuse
- Previous head injury
- Mental retardation
- Seizure disorders
Three major groups of brain blunt trauma:
- Epidural hematoma
- Subdural hematoma
- Parenchymal injuries
epidural hematoma. the result of trauma that causes a tear in the middle meningeal artery.
The rapid movement of the brain that occurs in trauma can tear the bridging veins that extend from the cerebral hemispheres through the subarachnoid and subdural space to empty into dural sinuses. These can be torn with trauma, particularly if there is significant cerebral atrophy that exposes these veins even more.
Traumatic Parenchymal Injuries:
- Impact of an object with the head
–It usually presents brain contusion ( A contusion is caused by rapid tissue displacement, disruption of vascular channels, and subsequent hemorrhage, tissue injury, and edema.)
–Caused both by coup injury and contercoup injury
- Penetration of the brain
–It usually presents brain laceration ( A laceration occurs with tissue tearing, vascular disruption, hemorrhage, and injury along a linear path.)
–Caused by a projectile such as a bullet or a skull fragment from a fracture
Morphology Traumatic Parenchymal Injuries:
Location:
- The frontal lobes along the orbital gyri and the temporal lobes
–crests of gyri are most susceptible
–cerebral cortex along the sulci is less vulnerable.