Head Injury Lecture

Question 1

What is Primary brain injury?

Answer 1

From the time of injury

Question 2

What is Secondary brain injury

Answer 2

Due to consequences of injury, partly preventable

Question 3

What is the pathophysiology of brain injury?

Answer 3

Release of excitatory amino acids (glutamate, aspartate)
Binding to receptors (eg NMDA)
Release of intracellular calcium, activation of phospholipases, breakdown of cell membrane, cell swelling, activation of apoptosis.

Question 4

How does Primary brain injury lead to Secondary brain injury?

Answer 4

Loss of blood-brain-barrier, leucocyte infiltration - inflammation
Loss of cerebral autoregulation of blood pressure - ischaemia
Loss of cerebral autoregulation of blood flow – metabolic de-coupling – even more ischaemia causing further brain oedema

Question 5

What is and what makes up CPP?

Answer 5

Cerebral perfusion pressure = mean arterial pressure – intracranial pressure

CPP = MAP - ICP

Question 6

After a head injury what CPP should you aim for?

Answer 6

> 60mmHg

ie MAP > 80mmHg and keeping ICP

Question 7

What is normal adult ICP?

Answer 7

9-11mmHg

Question 8

What is an open head injury?

Answer 8

Open - penetrating (missile)

Question 9

What is a closed head injury?

Answer 9

Acceleration/deceleration/rotation (non-missile)

Question 10

What does “raccoon” or “panda eyes” mean?

Answer 10

Skull base fracture - anterior cranial fossa

Question 11

What does the Battle sign over mastoid area

Answer 11

Middle cranial fossa - skull base fracture

Question 12

Focal signs (2)

Answer 12

Lateralising motor signs

Pupillary responses to light (3rd nerve palsy)

Question 13

What kills patients with head injury (3)

Answer 13

Hypoxia
Hypotension
Raised ICP

Question 14

How long before there is irreversible neuronal damage with circulatory arrest

Answer 14

5mins

Question 15

When should you request a CT head scan in trauma? (4)

Answer 15

Any patient with..
a skull fracture
not orientated (GCS

Question 16

Types of traumatic intracranial bleeding from outside to inside(6)

Answer 16

From outside to inside
Extradural haematoma
Subdural haematoma
Traumatic subarachnoid haemorrhage
Intracerebral contusion
Intracerebral haematoma
Intraventricular haemorrhage

Question 17

What are the considerations in Invasive Care Management (5)

Answer 17

Sedation
Ventilation
BP
Glucose
Temp.

Question 18

How does sedation help with intensive care of head injury? (3)

Answer 18

Reduces cerebral metabolic rate
Reduces cerebral blood flow
Reduces ICP

Question 19

How does ventilation help with intensive care of head injury? (2)

Answer 19

Maintains adequate oxygenation pO2 13-15kPa

Maintain normocapnia pCO2 4-4.5kPa

Question 20

What should you do to BP in an intensive care management of head injury

Answer 20

Maintain CPP of >60mmHg

Question 21

Cerebral Protection following injury (6)

Answer 21

CSF Drainage - reduces ICP
Mannitol - improves micro-perfusion
Hypertonic saline - may be better than mannitol
Hyperventilation - temporary effect 2-4hrs
Hypothermia
Decompressive craniectomy

Question 22

Late effects of head injury (3)

Answer 22

Epilepsy
CSF leak
Cognitive Problems

Question 23

Where can CSF leak?

Answer 23

Into the nose

Into the middle ear

Question 24

Cognitive problems after head injury

Answer 24

Post concussion syndrome

- Poor conc., headache, poor memory, lethargy