Head Injury

Question 1

How would you classify head injury

Answer 1

Type of injury
Distribution of lesions
Time course of damage following the traumatic event

Question 2

Examples of type of injury (which is more common)

Answer 2

Non-missile (more common)

Missile head injury

Question 3

What is meant by missile head injury

Answer 3

Head injury in which there is penetration of skull or brain

Question 4

Examples of distribution of lesions

Answer 4

Focal

Diffuse brain lesions

Question 5

Categories of time course of damage following the traumatic event

Answer 5

Primary

Secondary

Question 6

What is meant by Primary time course of damage following the traumatic event

Answer 6

Due to immediate biophysical forces of trauma

Question 7

What is meant by Secondary time course of damage following the traumatic event

Answer 7

Presenting some time after the traumatic event:

• Physiological responses to trauma
• Effects of hypoxia/ischaemia
• infection

Question 8

What is non-missile

Answer 8

Blunt head trauma

Question 9

Focal damage after non-missile trauma

Answer 9

Scalp
Skull (fracture)
Meninges
Brain

Question 10

Focal damage to scalp after non-missile trauma

Answer 10

contusions

lacerations

Question 11

Focal damage to meninges after non-missile trauma

Answer 11

Haemorrhage

Infection

Question 12

Focal damage to brain after non-missile trauma

Answer 12

Contusions (bruise)
Lacerations
Haemorrhage
Infection

Question 13

Diffuse brain lesions as result of non-missile trauma

Answer 13

Diffuse axonal injury
Diffuse vascular injury
Hypoxia-ischaemia
Swelling

Question 14

What can result from skull fracture (implies considerable force)

Answer 14

Increased risk of haematoma, infection and aerocele

Question 15

What can cause skull fracture

Answer 15

Angled or pointed objects cause localized fractures that are often open or depressed
Flat surfaces cause linear fractures
Can extend to skull base

Question 16

Examples of haemorrhage (focal lesion)

Answer 16

Extradural haematoma
Subdural haematoma
Traumatic subarachnoid haematoma
Cerebral and cerebellar haemorrhage

Question 17

Cause of superficial and deep cerebral/cerebellar haemorrhage

Answer 17

Superficial - due to severe contusion

Deep - related to diffuse axonal injury

Question 18

Describe extradural haemorrhage

Answer 18

~15% of fatal head injurys (~10% of severe ones)
Occur slowly over hours
Causes death by brain displacement
Raised intracranial pressure
Herniation

Question 19

Describe subdural haematoma

Answer 19

Usually due to tears in bridging veins (cross subdural space form superior surface of brain to mid-sagittal sinus
Can occur slowly
Usually surrounded by ‘membrane’ of granulation tissue

Question 20

Causes of traumatic subarachnoid haemorrhage

Answer 20

Contusions/lacerations
Base of skull # (tear vessels)
Vertebral artery rupture/dissection
Intraventricular haemorrhage

Question 21

Main cause of infection in brain

Answer 21

Skull fracture

Question 22

Focal brain damage mechanisms

Answer 22

Contact damage (at or just deep to the point of impact)
Acceleration or deceleration damage (force to head causes differential movement of skull and brain or get differential movement of brain tissue)

Question 23

What can result from differential movement of brain tissue

Answer 23

Shearing, traction and compressive stresses

Damages blood vessels and axons

Question 24

What can result from differential movement of skull and brain (as result of force to head)

Answer 24

Impact of inner surface of skull on underlying brain causes contusion
Traction on bridging veins causes subdural haemorrhage

Question 25

What are contusions

Answer 25

Superficial bruises of the brain

Question 26

What is difference between coup and contre coup contusions

Answer 26

coup = at site of impact

contre coup = away from site of impact

Question 27

Describe how contusions change over time

Answer 27

At first - haemorrhagic
Then become brown/orange and soft (days weeks)
Then indented or cavitated (after months or years)

Question 28

When do lacerations happen

Answer 28

When contusion is sufficiently severe to tear the pia mater

Question 29

Example diffuse lesions

Answer 29

Diffuse axonal injury
Diffuse vascular injury
Swelling
Hypoxia-ischaemia

Question 30

Pathophysiology of chronic traumatic encephalopathy

Answer 30

Atrophy:
-neocortex, hippocampus, diencephalon & mamillary bodies
Enlarged ventricles with fenustrated cavuum septum
Tau-positive neurofibrillary and astrocytic tangles:
-Frontal and temporal cortex and limbic regions
-Especially around depths of sulci and limbic regions

Question 31

What % of chronic traumatic encephalopathy is TDP-43 pathology

Answer 31

~85%