Traumatic Head and Spinal Cord Injury and Raised Intracranial Pressure Flashcards by Srishti D

What are the direct effects of trauma?

Scalp
- Lacerations
- Bruises
Skull
- Fractures
Meninges
- Vascular injury
- Lacerations
Brain/spinal cord
- Contusions
- Lacerations
- Diffuse axonal injury
- Diffuse vascular injury

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What are contusions?

Bruises on surface of brain

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How many vessels does diffuse vascular injury in the brain involve?

Single vessel or multiple tiny ones

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What is concussion?

Clinical term
Instantaneous loss of consciousness
Temporary respiratory arrest
Less of reflexes
Possible seizure
Follows sudden change in momentum of head
- Direct blow
- Decceleration
Pathogenesis uncertain
- Maybe effect at brainstem level

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What is the Glasgow coma scale?

Scale of neurological status
Enables standardisation between different groups of patients
- Therapies and outcomes can be assessed
Indicates level of brain injury

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What three aspects are taken into account in the Glasgow coma scale?

Eye opening
Best verbal response
Best motor response

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What is the maximum score that you can get on the Glasgow coma scale?

15 > okay

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What is a penetrating injury?

Direct disruption of tissue

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What is a closed injury?

Movement and compression of neural and vascular structures within bony confines

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What are the secondary effects of traumatic head injury?

Ischaemia
Hypoxia
Cerebral swelling
Infection
Epilepsy

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When do secondary effects of traumatic injury happen?

Delayed

Can contribute to immediate clinical outcome

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When does infection occur in traumatic head injury?

Later in clinical course if patient survives

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What does it mean if infection takes place after a traumatic head injury?

Brain or CSF breached

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When does epilepsy occur in traumatic head injury?

Late in clinical course

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Describe skull fractures

Radiate from point of impact
Can be depressed - bone pushes down on underlying brain
Important to diagnose because indicator of high energy transfer injury - brain has also moved around inside skull

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What is the difference between an open and closed skull fracture?

Open if communicates with surface, but closed if it doesn’t

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What is a comminuted skull fracture?

Bone splinters

Can chop away at brain tissue

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What does blood and/or CSF from the nose and/or ears indicate?

Basal fracture

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What most commonly ruptures in an extradural haematoma?

Middle meningeal artery

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Why is an extradural haematoma much more likely to happen in a younger patient than an older one?

As people age, dura becomes increasingly adherent to skull

So in younger people, dura not attached > high pressure bleed not compressed

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What ruptures in a subdural haematoma?

Subdural veins

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What kind of subdural haematomas are there?

Acute

Chronic

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Why are subdural haematomas more common in older patients?

As you age, brain shrinks and dura adheres to skull
Veins entering sinuses under more tension
More vulnerable to rupture
Can get from quite low energy transfer

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What is the most common injury to brain tissue?

Contusions

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Where do coup injuries happen?

At impact site

Where do contrecoup injuries happen?

Opposite side of brain to site of impact

Where do stereotypical contusions tend to occur?

Base of brain - Inferior frontal lobes - Inferolateral temporal lobes

What can directly damage brain tissue?

Force itself | Torn blood vessels

What reactive process do contusions involve?

Haemorrhagic necrotisation

Where must force be applied for contusions at the base of the brain to occur?

Anywhere

Why do people sometimes develop anosmia with contusions to the base of the brain?

Olfactory bulb pulverised

What happens to a contusion if the person survives?

Contusion resolves Damaged tissue phagocytosed Visible shrinkage of brain in these areas

How does the brain get lacerated?

Penetration by foreign body or skull fragments

How do missile injuries cause damage to brain tissue?

Via shock waves

Where is a particularly vulnerable site where cerebral tissue can tear?

``` Ponto-medullary junction Particularly in children Very rare Happens in severe brain trauma Accompanies other injuries ```

What are diffuse forms of brain injury?

Traumatic/diffuse axonal injury (TAI/DAI) Diffuse vascular injury Secondary injury

What is TAI/DAI?

Axons torn

What is diffuse vascular injury?

Little blood vessels torn

How do neurochemical alternations due to trauma exert toxic effects?

Brain tissue as it's damaged releases neurotransmitters and other substances that can cause further damage to surrounding brain tissue themselves

What happens to the axons in DAI?

Bulbous swelling and complete interruption of axon Axonal transport continues from cell body and collect in swelling Axon beyond that dies

What are the long term effects of DAI?

Decreases white matter Corpus callosum thins Ventricles dilate to compensate for tissue loss Patient severely neurologically impaired

Describe cord-compressive acute traumatic injury

Toothpaste effect Soft cord tissue squeezed along adjacent spinal cord both proximally and distally Tissue being pushed = necrotic Can be pushed towards brainstem and cause damage there

What are the longer term sequelae of brain trauma?

Infections Hydrocephalus Epilepsy Chronic traumatic encephalopathy

What can potentially be breached to cause an infection?

Scalp Skull Meninges Brain tissue

What causes epilepsy after brain trauma?

Number of conditions, including: - Tumours - Infarcts - Haemorrhages - Trauma

What is chronic traumatic encephalopathy?

Brain atrophy due to neuronal loss Abnormal deposition of tau protein Often diffuse deposition of A-beta plaques in cortex

How much blood and CSF is in the brain?

150 mL each

What is the initial response to an expanding brain lesion?

Expulsion of as much CSF and venous blood as possible

What happens after as much CSF and blood has been squeezed out from the brain in response to an expanding lesion?

Intracranial pressure rises

Where does herniation of brain tissue occur?

Through dural openings

What happens as ICP approaches MAP?

Brain perfusion ceases | Death occurs a bit before this though

What are some potential causes of raised ICP?

``` Trauma Tumour Infarction Haemorrhage Infection Cerebral oedema Overproduction, or obstruction of flow or absorption of CSF ```

What can cause an overproduction of CSF?

Choroid plexus papilloma

What are the two main subtypes of cerebral oedema?

Vasogenic | Cytotoxic

What is a vasogenic cerebral oedema?

Due to BBB disruption with increased vascular permeability Predominantly involves white matter Fluid between cells Quite sensitive to treatment; eg: steroid therapy

What happens in cytotoxic cerebral oedema?

``` Increased IC fluid secondary to neuronal, glial, or endothelial cell membrane injury Cells can't pump out water anymore Common in cerebral infarction Involves grey and white matter Not steroid responsive ```

Where does CSF come out from the brain?

Foramenae at brainstem level

What is the route that CSF takes?

Out of brain Into subarachnoid space Down into spinal cord Up and around cerebral vessels

Where is CSF absorbed into venous circulation?

Arachnoid granules that project into sinuses

What happens to CSF absorption with age?

Can decrease | Can cause raised ICP > has to be drained another way

In what order to herniations occur because of a subdural haematoma?

Subfalcine herniation of cingulate gyrus Distorted lateral ventricles Transtentorial herniation of medial temporal lobe Displacement and distortion of brainstem Tranforaminal herniation of cerebellar tonsil

What happens in a subfalcine herniation of the cingulate gyrus?

Brain tissue forced under falx cerebri

What problems do distorted lateral ventricles cause?

None

What happens in a transtentorial herniation of the medial temporal lobe?

Part of temporal lobe goes through same space as brainstem Constriction of blood vessels Occulomotor nerve close to here - eventually, compression can cause fixed dilated pupil on ipsilateral side

What has happened by the time the cerebellar tonsil herniates?

Patient on respirator or dead

What type of lesions cause a transforaminal herniation of the cerebellar tonsil earlier?

Posterior fossa expanding lesion

What causes brainstem haemorrhages with brainstem herniation?

Blood supply of brainstem fixed Tissue has been pushed down but vessels can't move Vessels tear

Traumatic Head and Spinal Cord Injury and Raised Intracranial Pressure Flashcards

(67 cards)