Neuropathology of Traumatic Brain Injury

Question 1

What percentage of trauma deaths are due to TBI?

Answer 1

25%

Question 2

What percentage of TBI patients make a good recovery?

Answer 2

31%

Question 3

Name at least 3 types of non-missile head trauma

Answer 3

Acceleration/deceleration, rotation, falls, assaults

Question 4

Describe the relationship between GCS score and TBI severity

Answer 4

GCS 13+ = mild injury, 9-12 = moderate injury, 8- = severe injury

Question 5

Describe a verbal GCS score of 3

Answer 5

Utters words, but they are inappropriate

Question 6

Describe a motor GCS score of 3

Answer 6

Abnormal flexion to pain - decorticate response

Question 7

Describe a motor GCS score of 2

Answer 7

Extension to pain - decerebrate response

Question 8

Describe an eye GCS of 2

Answer 8

Opens eyes to pain

Question 9

State at least 3 factors influencing the outcome from TBI

Answer 9

Age and brain atrophy, drugs (e.g. warfarin), nutrition, pre-existing disease, psychosocial status, genetic makeup

Question 10

Name at least 4 types of secondary injury

Answer 10

Ischaemia, raised ICP, seixures, oedema, infection, fever, hyperglycaemia

Question 11

Why do seizures occur in TBI?

Answer 11

Cytotoxic glutamate activity

Question 12

Name the 2 types of oedema in TBI

Answer 12

Vasogenic and cytotoxic

Question 13

State 5 factors involved in secondary injury

Answer 13

Mediators, calcium ions, receptor dysfunction, free radicals, inflammation

Question 14

Name at least 4 primary injuries in non-missile TBI

Answer 14

Scalp laceration, skull fracture, cerebral contusion, cerebral laceration (breach of pia & meninges into brain parenchyma), intracranial haemorrhage, diffuse axonal injury

Question 15

In fatal non-missile head injuries, how many patients have surface contusions?

Answer 15

95%

Question 16

Describe the difference between diffuse axonal injury and traumatic axonal injury

Answer 16

Diffuse axonal injury is a clinical and radiological phenomenon used to determine prognosis; traumatic axonal injury is the pathological phenomenon seen in tissue after the event

Question 17

State the 3 most common secondary injuries in fatal non-missile head injury

Answer 17

Raised ICP, ischaemic brain damage, brain swelling (oedema)

Question 18

What is Battle’s sign?

Answer 18

A bruise behind the ear that indicates a skull fracture

Question 19

What are raccoon eyes?

Answer 19

Periorbital haemorrhages which indicate a skull fracture

Question 20

Why are fissure fractures affecting the middle ear or anterior cranial fossa important?

Answer 20

They can cause CSF leakage and otorrhoea or rhinorrhoea, which increases infection risk

Question 21

Describe the difference between cerebral contusions and cerebral lacerations

Answer 21

Cerebral contusions are where the brain collides with the skull, producing a bruise on the brain surface. Cerebral lacerations are when this is severe enough to tear the pia mater

Question 22

State the most common sites for cerebral contusions

Answer 22

Lateral surfaces of the hemispheres and interior surfaces of the frontal and temporal lobes

Question 23

What causes diffuse axonal injury?

Answer 23

Shear and tensile forces affecting the axons

Question 24

Which structures are most commonly affected by diffuse axonal injury?

Answer 24

Midline structures - corpus callosum, rostral brainstem, septum pallucidum - due to the rotational nature of many traumas

Question 25

Describe the grading of diffuse axonal injury

Answer 25

1) Fibres affected in the parasagittal frontal lobe, internal capsule, and cerebellum 2) Fibres also affected in the corpus callosum 3) Fibres also affected in the dorsal brainstem

Question 26

Name a method of immunostaining for traumatic axonal injury

Answer 26

Immunostaining for amyloid precursor protein

Question 27

Describe the process of damage in primary axotomy

Answer 27

Disturbed calcium homeostasis activates calcium-dependent processes, especially calpain, leading to cytoskeletal disruption with disconnection and the development of swelling

Question 28

Why can repeated injury - e.g. in boxing - lead to axotomy?

Answer 28

The repair after initial axotomy is imperfect, leading to greater susceptibility to damage

Question 29

Name the types of intracranial haematoma

Answer 29

Extradural, subdural, subarachnoid, intracerebral, burst lobe

Question 30

Name the 3 types of brain swelling

Answer 30

Congestive, vasogenic, cytotoxic

Question 31

What causes cytotoxic brain swelling?

Answer 31

The increased water content of cells and cell lysis

Question 32

What causes congestive brain swelling?

Answer 32

Vasodilation and increased cerebral blood volume

Question 33

Name the 3 main brain herniation sites

Answer 33

Subfalcine, transtentorial, transforaminal

Question 34

Describe subfalcine herniation

Answer 34

A major space-occupying lesion above the tentorium causes the cingulate cortex just above the corpus callosum to herniate

Question 35

Describe transtentorial herniation

Answer 35

Supratentorial pressure cause the medial temporal lobe to herniate, shutting down cardiorespiratory centres

Question 36

Describe transformaminal herniation

Answer 36

The cerebellar tonsil herniates through the foramen magnum

Question 37

What is chronic traumatic encephalopathy?

Answer 37

A tauopathy at the base of the sulci as a result of multiple TBIs

Question 38

How can chronic traumatic encephalopathy be differentiated from AD?

Answer 38

Prominent astrocytic tau tangles in CTE - AD is a purely neuronal tauopathy

Question 39

State some behavioural symptoms of CTE

Answer 39

irritability, aggression, substance abude

Question 40

State some cognitive symptoms of CTE

Answer 40

Memory impairments, executive dysfunction, dementia

Question 41

State some mood symptoms of CTE

Answer 41

Depression, anxiety, suicidal ideation

Question 42

State some motor symptoms of CTE

Answer 42

Dysarthria, ataxia, parkinsonism

Question 43

What is ageing-related tau astrogliopathy?

Answer 43

The deposition of tau in astrocytes with age