Head Injury

Question 1

How does the anatomy of the head make it vulnerably to injury?

Answer 1

Enclosed in a rigid compartment so easily compressed when swelling/hematoma

Question 2

What is the significance of the Munro-Kelly doctrine?

Answer 2

• explains relationship between intracranial pressure and content
• brain, CSF and blood are usual contents so = fixed intracranial volume

Question 3

What is the compensated state of the brain?

Answer 3

• if space occupied by mass/swelling

- compensated for by displacing CSF into spine/venous blood into circulation

Question 4

What is the decompensated state of the brain?

Answer 4

• rising intra-cranial pressure
• decrease in cerebral perfusion pressure of the brain
• CPP = Mean arterial pressure - intracranial pressure

Question 5

What are the 3 types of herniation?

Answer 5

• sulfacine
• tentorial
• tonsillar

Question 6

What is a sulfacine herniation?

Answer 6

brain is pushed beneath the falx cerebri (often cingulate cortex)
- causes further pressure on ACA

Question 7

What is a tentorial herniation?

Answer 7

2 types

• lateral: compresses CN III causing down and out movement
• central: through tentorial notch

Question 8

What is a tonsillar herniation?

Answer 8

Through foramen magnum of cerebellar tonsils

- compresses brainstem and can stop breathing

Question 9

What are the layers of the scalp?

Answer 9

S - skin
C - connective tissue
A - aponeurosis
L - loose connective tissue
P - pericranium

Question 10

What are the 3 layers of the meninges?

Answer 10

Dura, arachnoid and pia mater

Question 11

What are the main types of traumatic brain injury?

Answer 11

• extradural haematoma
• subdural haemorrhage
• subarachnoid haemorrhage
• orbital blow out fractures
• C spine

Question 12

What are the features of a extradural haematoma?

Answer 12

• impact
• when vessel running between skull and dura is torn
• damage to artery or large venous sinus
• accumulates slowly

Question 13

Which artery is normally torn in an extradural haematoma?

Answer 13

idle meningeal artery

Question 14

Why do extradural haematomas accumulate slowly?

Answer 14

Dura is strongly adhered to the inner skull so enlarged clot will slowly strip dura from the skull

Question 15

What are the features of a subdural haemorrhage?

Answer 15

• caused by movement of the brain (acceleration/deceleration)
• brain movement lags skull movement so there is friction within the subdural space
• this tears bridging veins
• blood can spread out across space quickly

Question 16

What are the features of a subarachnoid haemorrhage?

Answer 16

On hemisphere surface

• oedema
• fracture sites/contusions

Question 17

What is an orbital blow out fracture?

Answer 17

Damage to lamina papyracea which causes mucous to encounter brain lead to infections

Question 18

What is the lamina papyracea?

Answer 18

Covers the ethmoid air sinuses

Question 19

What is a C spine injury?

Answer 19

• blow to the head/deceleration injures spine

Question 20

What happens after traumatic brain injury?

Answer 20

Brain evolves:

• axons separate/retraction balls seen
• neurons undergo apoptosis
• cytotoxic oedema (injured cells lose energy)

Question 21

What is a coma?

Answer 21

• Inability to open eyes, vocalise words and obey simple commands

Question 22

What are the effects of a coma on the body?

Answer 22

• affects respiration and circulation
• depresses cough, gag and swallow
• slow ventilation
• decreases blood pressure

Question 23

How to manage traumatic brain injury?

Answer 23

• resuscitation
• CT early
• neurosurgery referral rapid
• neurointensive care
• rehab

Question 24

What does resuscitation aim to do?

Answer 24

Restore airways
Immobilise patient
Preserve brain function