Head Injury

Question 1

What is the pathophysiology in a primary brain injury?

Answer 1

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 2

What is the pathophysiology in a secondary brain injury?

Answer 2

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 3

What does cerebral perfusion pressure equal?

Answer 3

CPP=MAP-ICP

Question 4

What CPP should be aimed for after head injury?

Answer 4

> 60mmHg

Question 5

What physical findings can be found in head injury?

Answer 5

Scalp swelling/laceration
Skull vault fracture- linear, depressed, compound
Skull base fracture- ACF:panda eyes, MCF:Battle sign

Question 6

What are the eye opening components of the GCS?

Answer 6

Spontaneously
To command
To pain
None

Question 7

What are the verbal response components of the GCS?

Answer 7

Orientated
Confused
Inappropriate words
Incomprehensible sounds
None

Question 8

What are the best motor response components of the GCS?

Answer 8

Obeys commands
Localised pain
Flexes to pain
Abnormal flexion
Extension
None

Question 9

What is the definition of a coma?

Answer 9

Does not open eyes, obey commands, or speak. GCS <=8

Question 10

What kills patients with head injury?

Answer 10

Hypoxia
HT
Raised ICP

Question 11

Within what time does irreversible neuronal damage occur in circulatory arrest?

Answer 11

5 minutes

Question 12

What percentage of carried glucose does the brain use?

Answer 12

12%

Question 13

When should a head CT be requested in trauma?

Answer 13

Any patient with: (1 required)
a skull fracture
not orientated (GCS <15)
with focal neuro signs
taking anti-coagulants

Question 14

What are the types of traumatic intracranial bleeding from outside to in?

Answer 14

Extradural haematoma
Subdural haematoma
Traumatic subarachnoid haemorrhage
Intracerebral contusion
Intracerebral haematoma
Intraventricular haemorrhage

Question 15

What is the intensive care management of head injury?

Answer 15

Sedation-Reduces cerebral metabolic rate, reduces cerebral blood flow, reduces ICP
Ventilation- Maintain adequate oxygenation
Maintain normocapnia
BP-Manipulate to maintain CPP of >60mmHg
Glucose- Maintain normoglycaemia
Temperature- Maintain euthermia

Question 16

What cerebral protection can occur following injury?

Answer 16

CSF Drainage - reduces ICP
Mannitol- improves micro-perfusion
Hypertonic saline- may be better than mannitol
Hyperventilation- temporary effect (2-4 hrs)
Hypothermia- weak evidence for effect
Decompressive craniectomy – randomised trial underway

Question 17

What is post concussion syndrome?

Answer 17

Poor concentration, headache, poor memory, lethargy post-head injury