Pathology of head injury Flashcards
Example of primary insult
Focal/diffuse brain trauma
Example of secondary insult
- Hypotension
- Hypoxia
- Infection
- Haematoma
How to assess
Initial assessment: Glasgow coma scale (1-15 )
13-15: mild injury
9-12: moderate injury
3-8: severe injury
Consequences of a head injury
- Permanent physical disability
- Post-traumatic epilepsy
- Intracranial infection
- Psychiatric illness
- Chronic subdural haematoma
- Punch-drunk dementia- dementia associated with head injury
- Fatal outcome
How do head injuries occur?
- Debilitating disease can lead to falls
- Accidental
- Homicidal
Different types of scalp injuries
Abrasions/ lacerations / bruises/ incisions/ thermal injuries
What is the difference between a laceration and an incision
- Laceration:Blunt force to tissue which causes ragged incision and laceration which is supported by other stronger tissues
- Incisions: Sharp force causing neat, unbridged wound
What causes bruising
What can type of bruising Indicate
- blunt trauma to head which causes blood to leak
- pattern of bruising can tell us more about what happened
What causes a black eye
blood collects around eye as a result of injury to brow
What does the skull encompass
Skull completely encompasses the brain and the meninges except for the foramen magnum.
Which are the two parts of the skull?
Skull vault which covers the bones and their sutures
Skull base: part of the skull which the brain rests on which can be divided into anterior, middle and posterior cranial fossa
Which are the different types of skull fissures
- Linear
- Depressed
- Ring
- Comminuted
- Coutre-coup
What is a linear fracture
Usually at parieto-temporal level
Usually from fall onto side or top of head
May continues into skull base
Hinge fracture
What is a depressed fracture
- Fracture which leads to fragments of the brain being pushed in against blood vessels, meninges and brain
- Risk of meningitis
- Risk of post-traumatic epilepsy
What is a comminuted fracture
Fragmented skull
What is a ring fracture
Fracture which affects the foramen magnum
Usually due to the brainstem and the spinal cord being impacted against each other
Resulting from a fall from a height which results in you landing on feet
What is a contre coup fracture
Fracture resulting from hitting head on back
Leads to damage in the anterior cranial fossa
Types of intracranial hemorrage
Extradural
subdural
Subarachnoid
Extradural hemorrage
Blood between the dura and the skull
Build up of blood here will eventually lead to the dura being pulled off the skull
Usually associated with large pressure arteries rather than veins in reaction to a skull fracture
Commonly associated with a Middle meningeal artery rupture of the pterion
Build up of intracranial pressure- can take hours for symptoms to present:
- Patient may have a lucid period where they appear to be completely fine
- This can have catastrophic consequences
Subdural hemorrage
Bleeding underneath the dura, usually associated with bridging veins which drain the venous channels of the dura.
Can be caused by any action which appears to shear these vessels due to the movement between the brain and the dura- not necessarily associated with a skull fracture.
Very common in people with atrophic brain as the brain is more flexible so more room for the veins to stretch.
Can present as chronic in the elderly- leads to confusion so often mistaken with dementia
Can have a lucid period
subarachnoid hemorrage
Most common cause is natural disease- e.g. ruptured cerebral artery
Often associated with bruising of the brain
Usually rapid death due to irritant effects of blood in brain
What is traumatic SAH?
Traumatic basal SAH is a separate entity in forensic science- it is associated with a severe blunt to the neck which cause rotational movement of head- this causes the circle of willis to become ruptured and SAH on the base of the brain.
Different kinds of intrinsic brain damage
- Cerebral oedema
- Cerebral contusion
- Diffusion axonal injury
Cerebral oedema
Rapid result of brain injury
Can lead to XS swelling which leads to massive increase in intracranial pressure- sudden death.
Cerebral contusion
Direct mechanical damage to the brain
Coup contusion:
- when head stuck with blunt force
- Contusion is found directly under the strut area
Contre-coup:
- when moving head strikes against object
- Contusions are found diametrically opposite the site of head impact
Diffuse axonal injury
- Diagnosis can only be made based on microscopy of the brain
- Small vessels involved/damaged may increase suspicions
- Usually associated with vehicle incident/ falls from a height
- Rotational forces to the head lead to shearing of axons
Which are the most common area of DAI
Areas which are most prone are:
- corpus callosum
- Cereberllar peduncles
- Posterior internal capsule
- para-sagittal white matter
