Session 9 - Head Trauma And Acute Intracranial Events

Question 1

What are the two types of primary head injuries?

Answer 1

Focal

Diffuse

Question 2

What are the different types of focal head injuries?

Answer 2

Haematoma

Contusion

Question 3

What are the different types of diffuse head injuries?

Answer 3

Concussion

Diffuse axonal injury

Question 4

What are the different types of haematoma?

Answer 4

Extra dural
Subdural
Intracerebral

Question 5

What are the different types of contusion?

Answer 5

Site of impact (Coup)

Site opposite impact (Contre-coup)

Question 6

What is meant by a secondary head injury?

Answer 6

Injury is indirect, a complication of a worsening primary injury that has a delayed onset after the original primary injury.

Question 7

What is a cerebral contusion?

Answer 7

‘Bruising’ of the brain whereby blood mixes with the cortical tissue due to microhaemorrhages and small blood vessel leaks.

Question 8

Explain the pathophysiology of cerebral contusions.

Answer 8

Trauma causes microhaemorrhages.
Cerebral contusion forms.
Cerebral oedema/intracerebral bleed leads to raised ICP. This could lead to coma.

Question 9

What is a concussion?

Answer 9

Head injury with temporary loss of brain function.

Question 10

Explain the pathophysiology involved in concussion.

Answer 10

Trauma causes stretching and injury to axons.
This impairs neurotransmission, causes a loss of ion regulation and a reduction in cerebral blood flow.
Results in temporary brain dysfunction.

Question 11

Give some examples of symptoms involved in post concussion syndrome?

Answer 11

Difficulty thinking clearly 
Difficulty concentrating
Difficulty remembering new information
Headache
Nausea or vomiting
Dizziness
Sensitivity to light or noise
Irritability 
More emotional 
Anxiety
Sleeping more than usual 
Sleeping less than usual
Trouble falling asleep

Question 12

What is diffuse axonal injury?

Answer 12

Shearing of interface between grey and white matter following traumatic acceleration/deceleration or rotational injuries to the brain damaging the intracerebral axons and dendritic connections.

Question 13

Explain the pathophysiology associated with diffuse axonal injury.

Answer 13

Trauma leads to shearing of grey and white matter interface.
This causes axonal death leading to cerebral oedema and therefore raised intracranial pressure.
This can lead to coma.

Question 14

What is a basilar skull fracture?

Answer 14

Bony fracture within the base of the skull (temporal, occipital, sphenoid or ethmoid bone)

Question 15

Explain the pathophysiology associated with a basilar skull fracture.

Answer 15

Trauma causes bone fracture which can cause tears in the meninges. This would lead to CSF leakage.

Question 16

What are the clinical signs of a basilar skull fracture?

Answer 16

Raccoon eyes
CSF rhinorrhea
CSF otorrhea
Battle sign 
Haemotypanum

Question 17

What are the layers of the meninges?

Answer 17

Pia mater
Subarachnoid space
Arachnoid
Dura mater (meningeal layer)
Dura mater (periosteal layer)

Question 18

Where does bleeding occur in a extradural haemorrhage?

Answer 18

Between the inner surface of the skull and the periosteal dura mater.

Question 19

What is the most common cause of extradural haemorrhage?

Answer 19

Trauma and/or skull fracture.
90% of cases involve a severed artery - most commonly the middle meningeal artery.
Venous involvement rare but is usually the result of a torn venous sinus.

Question 20

How will patients with a extradural haemorrhage present?

Answer 20

Patient will present with loss of consciousness due to impact of initial injury.
Followed by transient recovery with ongoing headache know as a ‘lucid interval’ in 40% of patients.
As haematoma enlarges, ICP will increase causing compression of the brain and rapidly deteriorating levels of consciousness.
Cranial nerve palsies may be found on examination as brain structures herniate.

Question 21

What will an extradural haemorrhage look like of CT?

Answer 21

Lemon shaped

Midline shift

Question 22

Prognosis of extradural haemorrhage is generally good with early intervention, however what complications might occur if it is left untreated?

Answer 22

Permanent brain damage
Coma
Seizures
Weakness
Psuedoaneurysm 
Arteriovenous fistula

Question 23

Where does bleeding occur in a subdural haemorrhage?

Answer 23

Between the meningeal dura mater and arachnoid mater.

Question 24

What causes a subdural haemorrhage?

Answer 24

Bleeding occurs due to shearing forces on cortical bridging veins. Most often associated with trauma but can be spontaneous. Cerebral atrophy increase the risk of rupture.
Could be acute, subacute or chronic.

Question 25

Chronic subdural haemorrhage can present with symptoms similar to what other disease?

Answer 25

Dementia. Chronic SDH may present with insidious onset of confusion and general cognitive decline.

Question 26

How do subdural haemorrhages present on CT?

Answer 26

Banana shaped Doesn’t cross the midline due to the falx cerebri Midline shift

Question 27

How do acute and chronic subdural haemorrhages look different on CT?

Answer 27

Acute - hyper dense i.e. brighter than brain tissue | Chronic - progressively hypodense over time i.e darker than brain tissue

Question 28

What two neurosurgical methods can be used to relieve raised intracranial pressure?

Answer 28

Burr hole | Craniotomy

Question 29

Where does bleeding occur in a subarachnoid haemorrhage?

Answer 29

Between the arachnoid mater and the pia mater.

Question 30

What are the usual causes of subarachnoid haemorrhage?

Answer 30

Vast majority of subarachnoid haemorrhages occur spontaneously secondary to ruptured berry aneurysm but may also be traumatic.

Question 31

How will patients with subarachnoid haemorrhage present?

Answer 31

``` Sudden onset ‘thunderclap’ headache Meningism (nuchal rigidity (neck stiffness), photophobia, headache) Nausea and vomiting Fever Focal neurological deficits Loss of consciousness ```

Question 32

What are the risk factors for berry aneurysms?

Answer 32

Family history Hypertension Heavy alcohol consumption Abnormal connective tissue; autosomal dominant polycystic kidney disease, Ehlers-Danlos, neurofibromatosis, Marfan’s

Question 33

Do berry aneurysms present with symptoms?

Answer 33

Largely asymptomatic it symptoms may arise if compressing on nearby structures or during early stages of rupture.

Question 34

What surgical procedures can be performed if there is a high risk of berry aneurysm rupture?

Answer 34

Surgical clipping | Endovascular coiling

Question 35

Where are the most common sites of aneurysm formation?

Answer 35

Generally occur at bifurcations: - bifurcation of anterior cerebral artery - bifurcation of internal carotid - bifurcation of posterior cerebral artery

Question 36

What procedure can be used to help diagnose a subarachnoid haemorrhage?

Answer 36

Lumbar puncture - presence of red blood cells or xanthochromia (red blood cell breakdown)

Question 37

Outline how a subarachnoid haemorrhage managed.

Answer 37

``` Stabilise patient Prevent rebleeding Treat cerebral vasospasm Correct hyponatraemia Neurosurgical intervention if a large bleed ```

Question 38

What are some possible complications of a subarachnoid haemorrhage?

Answer 38

``` Hydrocephalus Focal neurological deficits Coma Seizures Cognitive decline Frequent headaches Hypopituitarism ```