Cranial Trauma + 3rd CN Palsy

Question 1

The blood vessels in the scalp do not vasoconstrict as well as other blood vessels. What is the significance of this?What layer of the scalp includes these blood vessels?

Answer 1

The connective tissue layer contains the blood. vessels => heavy bleeding if lacerated

Question 2

The scalp is relatively loose, what layer of the scalp allows for this?

Answer 2

Loose areolar tissue allow for free scalp movement

Question 3

What are the layers of the scalp and meninges in order from superficial to deep

Answer 3

Question 4

Lacerations at which layer would require suturing? Why?

Answer 4

Lacerations at or deeper than the Aponeurosis need suturing as the aponeurosis will pull back exposing the underlying Loose areolar tissue.
Infection of this layer, which is now exposed, can spread intracranially causing meningitis or abscess formation

Question 5

Define a Concussion
What is the expected prognosis?

Answer 5

It is a minor head injury leading to confusion, headache, amnesia and visual disturbances

Typically has good prognosis and full recovery

Question 6

What are the 4 different types of brain fractures?

Answer 6

1) Simple
2) Open
3) Depressed
4) Base of Skull

Question 7

A simple fracture is a linear closed fracture. Fracture of which cranial bone would most indicate a high energy impact?

How is a simple fracture managed?

Answer 7

Occipital bone fractures suggest very high energy impact as it is the thickest cranial bone

Simple fractures do not involve displacement and hence usually no surgery unless brain injury involved (more from displaced fractures)

Question 8

An open skull fracture involves breach of skin or sinus mucosa and hence higher risk of infection. What is the management of an open skull fracture?

Answer 8

Wash + suture lacerations +/- antibiotics

Question 9

What is the management of a depressed skull fracture?

Answer 9

elevation

Question 10

Give examples of base of skull fractures

Answer 10

Racoon eye
Battle sign
CSF Rhinorrhoea
CSF Otorrhoea

Question 11

CSF rhinorrhoea is caused by compromise of the?
How is it checked for on examination/history?

If a patient with CSF rhinorrhea is admitted, what clinical procedure is relatively contra-indicated?

Answer 11

CSF rhinorrhoea occurs secondary to the compromise of the Cribriform plate

Hx: Fluid coming out of nose when bending over (e.g. picking something up or gardening)
Exam: Ask patient to bend over

Caution when inserting NG tube

Question 12

CSF otorrhoea is caused by compromise of the?
(2)

Answer 12

Tegmen Tympani
Tegmen Mastoideum

Question 13

Coup vs contrecoup

Answer 13

Question 14

Define a Diffuse Axonal injury
What would show on CT brain?

Answer 14

Shearing of axons typically occurring wiith rapid acceleration and deceleration

CT brain would look relatively normal with
1) Tiny hyperdensities secondary to Punctate haemorrhages (which occur at the white-grey junction =>)
2) Loss of grey-white matter differentiations

Question 15

When discussing head injuries, there are primary and secondary head injuries.

Name the primary (4) and secondary (6+) head injuries.

Which of the primary types carry the highest risk of herniation?

Answer 15

Question 16

In the setting of head injury, what is the ideal MAP?
Ideal ICP?

Answer 16

MAP >65
ICP 10-15

Question 17

What ICP is an indication for intervention?

Where is the ICP probe typically inserted into? Why?

In an ideal situation, where should the ICP probe be inserted into in order to achieve the most accurate results?

Answer 17

ICP 22+
(Normal 10-15)

ICP is typically inserted into the frontal horn of the lateral ventricle of the non-dominant hemisphere. This allows for CSF drainage as well to reduce ICP if needed.

the most accurate location is !!at the level!! of the foramen of monroe

Question 18

Cerebral blood flow depends on 3 different components. What are they?

Which of the 3 components are lost in head injury?

When managing a head injury, what measurement is used to assess for cerebral blood flow?

What is the target range of this measurement?

Answer 18

Question 19

Discuss the Munroe-Kellie Doctrine

Answer 19

Question 20

What are the 4 main types of brain herniation

Which is most associated with 3rd cranial nerve palsy?

Which is most associated with mortality? Why?

Answer 20

Question 21

What is Cushing’s triad for Brainstem compression?

Answer 21

Recall this occurs due to compression of the cardio-resp centres (Tonsillar herniation through foramen magnum)

Question 22

A patient post-head injury is undergoing Primary assessment. You are about to assess for pupillary light reflex. What finding would you expect to see in a case of Transtentorial herniation?

Answer 22

Transtensorial = Uncal => compression of the 3rd CN
=> Absent direct pupillary reflex due to mydriasis but consensual constriction is intact due to it being a unilateral compression => ipsilateral symptoms

Question 23

After a head injury what CN is most likely to be affected

Answer 23

6th CN due to it having the longest course

Question 24

What is the presentation of CN 3 palsy?

Answer 24

Question 25

What are the causes of 3rd CN palsy? Give at least 6/8

Answer 25

Under Uncal herniation/raised ICP => causes of raised ICP => SOL (Tumour, abscess, haematoma/haemorrhage, hydrocephalus, inflammation...)

Question 26

What is meant by Decerebrate vs Decorticate?

Answer 26

Question 27

Go through the GCS in full as you would in a long case with explanation of what to do

Answer 27

Question 28

What is meant by Primary, secondary and tertiary assessment as part of the ATLS protocol for managing a Head injury (No need for details just how to approach)

Answer 28

Question 29

What are the 2 types of Ventricular shunts?

Answer 29

Can be internal or external Internal (VP) requires a surgical procedure passing drain from ventricle to peritoneum (typically in the tx of hydrocephalus and congenital causes) External is done for head injuries whereby the cylinder drain is kept at ear level in order to maintain equilibrium and not drain an excessive amount of CSF

Question 30

When is a decompressive craniotomy escalated to a decompressive craniectomy? Where would the bone be stored once extracted?

Answer 30

If the brain begins expanding on decompression near or beyond its original size, a craniectomy is performed instead The bone is stored in the abdomen

Question 31

a patient presents with a head injury and is admitted after primary assessment at part of the ATLS protocols. An ICP probe is inserted into their skull with the most recent reading showing ICP of 22 and CPP is determined to be 71. How will you manage this patient at this stage along with escalations

Answer 31

Do not forget: 1) raised ICP due to inflammation can be treated via steroids => Methylprednisolone 2) ICP probe is inserted into the frontal horn of the lateral ventricle of the non-dominant hemisphere and hence can be used therapeutically to drain ICP if needed.