Pathology of Head Injury Flashcards
Why does any increase in volume within the skull lead to an increase in pressure?
The skull is not expandable
Define injury.
Injury is a transfer of energy to the body
How does velocity affect injury?
Increasing velocity will increase the impact and therefore the injury
What is a bruise?
Damage of little blood vessels resulting in leakage into the subcutaneous tissue
What are bruises the result of?
Blunt force trauma
Describe the formation of peri-orbital bruising.
- Blood will track through the looser tissues and the planes through which it can move
- Can be a result of a direct blow
What are bilateral black eyes usually caused by?
Usually a head injury or at the base of the skull. This is due to tracking of blood
What is an abrasion/graze?
-Injury to the superficial part of the skin caused by friction
How do abrasions usually heal?
Without scarring
What is a laceration?
- Tear or split in the skin due to the application of energy
- It is not a true cut
What is the cause of a laceration?
Blunt force injury
What must you do when treating lacerations?
-Explore for damage and foreign bodies
How do lacerations occur?
Skin splits at the weakest point and causes damage to surrounding tissue
What is an incision?
- Sharp force wound caused by cutting when energy is delivered over a very small area
- It is a true cut
How are incisions treated?
Easily stitched as they do not cause damage to the surrounding area
Give examples of types of injuries.
- Thermal injuries
- Incisions
- Lacerations
- Abrasions
- Bruises
Give examples of types of skull fractures.
- Ring fracture
- Fissure fracture
- Depressed fracture
- Hairline fracture
What is a ring fracture?
-The skull is a sphere and therefore fractures continue in a spherical fashion
What structure is often involved in a ring fracture?
- Foramen magnum
- Diastasis of sutures if sufficient energy
What parts of the skull are more susceptible to ring fractures?
Petrous temporal bones meeting the flood of the skull which may result in a basal fracture
What is a fissure fracture?
- Dissipated energy
- Not enough energy to complete a full ring
What are fissure fractures usually the result of?
Blunt force trauma
What does a depressed fracture indicate?
Indicates a little piece of bone has been pushed inwards by the application of energy
What is indicative of the weapon used in a depressed skull fracture?
Shape and size of fracture
What can depressed skull fractures result in?
Post-traumatic epilepsy
What is a hairline fracture?
Barely noticeable fracture that usually does not require treatment
What can hairline fractures lead to?
Infection if involves structures such as the nose or ear
When can hairline fractures become complicated?
When they impinge on other structures
What structure is closely applied to the skull?
Dura mater
What retains the configuration of the brain?
Pia mater
What is the extradural space?
Extradural space is a potential space and requires the dura to be stripped from the skull
What is an extradural haemorrhage?
Blood accumulating between skull and dura
What causes extradural haemorrhages?
Bleeding meningeal arteries
What are extradural haemorrhages usually associated with?
Skull fractures that traverse arteries
What is a subdural haemorrhage?
Bleeding between the dura and arachnoid mater
What do subdural haemorrhages occur as a result of?
-Occur as the brain moves in relation to the dura. The skull stops moving when it comes into contact with a stationary surface but the brain keeps moving. The emissary veins become stretch and burst. This results in an increase of pressure
What type of injury is a subdural haemorrhage?
Acceleration/ deceleration injury
Who are more susceptible to subdural haemorrhages?
-Alcoholics and the elderly are more susceptible due to brain shrinkage
What traumatic event can subdural haemorrhages occur in in infants?
Shaken baby syndrome
-The chin impacts the chest but the brain continues accelerating
What are subdural haemorrhages not usually associated with?
Skull fractures
What is a subarachnoid haemorrhage?
Bleeding between the arachnoid and pia mater
What are spontaneous subarachnoid haemorrhages usually due to?
Ruptured berry aneurysm
What are traumatic subarachnoid haemorrhages usually the result of?
Traumatic is usually due to sudden movements of the head with acceleration and rotatory components
How can a strike to the chin/neck result in a subarachnoid haemorrhage?
- Can be caused by strike to the neck or near the chin which causes the head to extend backwards
- In the extra vertebral course of the vertebral artery, there can be damage and dissection which can track up.
What are the 2 types of cortical contusions?
- Coup
- Contrecoup
What is a coup cortical contusion?
Where the direct blow occurs there will be a contusion
What is a contrecoup cortical contusion?
- Further contusion diametrically opposite where the force strikes
- May be larger than the coup injury
What natural disease can result in an intracerebral haemorrhage?
-Hypertension
-AV anomaly
-Amyloid angiopathy (makes vessels very delicate)
Vascular tumours
How can trauma cause intracerebral haemorrhage?
Sufficient energy delivered to the brain may result in a deep contusion which can destroy vessels and vulnerable vessel
When do diffuse axonal injuries occur?
Occurs where there is a large acceleration force on the brain with rotation
What is the usual prognosis of diffuse axonal injuries?
- Usually fatal
- Death may be instantaneous
- Some will be declared brain dead at hospital
What may be considered a very minor form of diffuse axonal injury?
Concussion
What are diffuse axonal injuries?
Glide haemorrhages in the corpus callosum
