Pathology of head injury

Question 1

Example of primary insult

Answer 1

Focal/diffuse brain trauma

Question 2

Example of secondary insult

Answer 2

• Hypotension
• Hypoxia
• Infection
• Haematoma

Question 3

How to assess

Answer 3

Initial assessment: Glasgow coma scale (1-15 )
13-15: mild injury
9-12: moderate injury
3-8: severe injury

Question 4

Consequences of a head injury

Answer 4

• Permanent physical disability
• Post-traumatic epilepsy
• Intracranial infection
• Psychiatric illness
• Chronic subdural haematoma
• Punch-drunk dementia- dementia associated with head injury
• Fatal outcome

Question 5

How do head injuries occur?

Answer 5

• Debilitating disease can lead to falls
• Accidental
• Homicidal

Question 6

Different types of scalp injuries

Answer 6

Abrasions/ lacerations / bruises/ incisions/ thermal injuries

Question 7

What is the difference between a laceration and an incision

Answer 7

• 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

Question 8

What causes bruising

What can type of bruising Indicate

Answer 8

• blunt trauma to head which causes blood to leak

- pattern of bruising can tell us more about what happened

Question 9

What causes a black eye

Answer 9

blood collects around eye as a result of injury to brow

Question 10

What does the skull encompass

Answer 10

Skull completely encompasses the brain and the meninges except for the foramen magnum.

Question 11

Which are the two parts of the skull?

Answer 11

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

Question 12

Which are the different types of skull fissures

Answer 12

• Linear
• Depressed
• Ring
• Comminuted
• Coutre-coup

Question 13

What is a linear fracture

Answer 13

Usually at parieto-temporal level
Usually from fall onto side or top of head
May continues into skull base
Hinge fracture

Question 14

What is a depressed fracture

Answer 14

• 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

Question 15

What is a comminuted fracture

Answer 15

Fragmented skull

Question 16

What is a ring fracture

Answer 16

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

Question 17

What is a contre coup fracture

Answer 17

Fracture resulting from hitting head on back

Leads to damage in the anterior cranial fossa

Question 18

Types of intracranial hemorrage

Answer 18

Extradural
subdural
Subarachnoid

Question 19

Extradural hemorrage

Answer 19

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

Question 20

Subdural hemorrage

Answer 20

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

Question 21

subarachnoid hemorrage

Answer 21

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

Question 22

What is traumatic SAH?

Answer 22

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.

Question 23

Different kinds of intrinsic brain damage

Answer 23

• Cerebral oedema
• Cerebral contusion
• Diffusion axonal injury

Question 24

Cerebral oedema

Answer 24

Rapid result of brain injury

Can lead to XS swelling which leads to massive increase in intracranial pressure- sudden death.

Question 25

Cerebral contusion

Answer 25

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

Question 26

Diffuse axonal injury

Answer 26

• 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

Question 27

Which are the most common area of DAI

Answer 27

Areas which are most prone are:

• corpus callosum
• Cereberllar peduncles
• Posterior internal capsule
• para-sagittal white matter