AP: Cerebral Trauma Flashcards
What are 2 important features in trauma to brain and spinal cord?
Severity and site
What does the magnitude and distribution in TBI depend on?
- Shape of object causing the trauma (pattern injury)
- The force of the impact
- Whether head is in motion or stationary at time of impact
What are 3 types of contusions (bleeds on surface of the brain?)
- Coup contusions
- occur beneath or at site of impact in absence of fracture
- Contrecoup contusions
- occur opposite side of side of impact
- normally occurs at frontal or temporal lobes (falling backwards)
- Fracture contusions
- occur beneath fracture
What is a laceration and where do they occur?
Tear in the brain tissue, they occur in regions where the inner skull is rough or there is a fracture of the overlying skull
Explain the aetiology of a traumatic axonal injury (TAI)
- Clinical syndrome.
- Primary injury.
- Mechanical distortion of the head results in movement of one region of brain relative to another - compromises axonal integrity and function.
- Combination of events in the axons.
- Process is set in motion at the time of injury and evolves over hours, days, months.
How common is traumatic axonal injury for patients in a coma?
50% of patients who develop coma after trauma have this form of white matter damage
Explain the pathophysiology of traumatic axonal injury?
Microtubules in axon become damaged, although initially the patient appears fine.
- FROM LECTURE: Kink in microtubule → accumulation of protein that flows down it → axonal bulbs accumulate after 3-4 hrs.
Where does TAI normally occur?
- Corpus callosum
- Haemorrhage of corpus callosum is a common diagnostic feature of TAI.
- Left and right hemispheres move independently → corpus callosum has twisted and stretched, and the vessels have torn and bled.
- Haemorrhage of corpus callosum is a common diagnostic feature of TAI.
- Cerebral white matter
- Internal capsule
- Brain stem:
- fornices
- midbrain
- pons
- medulla
- cerebellum
What is an extradural haematoma?
- Acute or chronic
- Blood in the extradural space between the dura and inner skull surface
- Typically patient has a lucid interval before neurological signs appear
- Associated w/ fracture
- tempoparietal regions - fracture squamous temporal bone
- Neurosurgical emergency requiring drainage to prevent death
What are the causes of extradural hematoma?
Has to be quite forceful:
- Arterial bleed: middle meningeal artery forms ovoid mass
- Tearing of venous sinuses
- Heat fractures of the skull in fire-related deaths
What is a subdural haematoma?
Subdural haemorrhage with blood in the subdural space
2 types:
- Burst lobe - related to contusions and lacerations
- Rupture of bridging veins - acute or chronic, often no associated brain damage
Blood confined to cerebral hemisphere, restricted by the falx.
Not well circumscribed, not distinct borders.
When might a subdural haematoma occur?
Where cerebral atrophy occurs
- Elderly
- Dementia
Non-atrophic cause:
- Alcoholics ⇒ chronic SDH
- No signs or symptoms.
Increased space to accommodate the bleed without affecting the brain.
Explain the 2 kinds of vertebral artery injuries?
- Intracranial - subarachnoid haemorhage
- arterial dissection - due to damage to the intima and media
- vertebral and basilar arteries supply the brainstem
- sudden unexpected movement of the head (punch, kick or weapon) and the brain rotates and the vessel is injured
- Extracranial
- damage to the endothelium or atherosclerosis result in embolic strokes
- sudden movement of neck can lead to damage to vessal wall with blood through the media
- formation of a thrombus and subsequent thrombus
- What shape are contusions?
- Why are they a yellow-brown colour?
- Wedge-shaped.
- Deposition of haemosiderin.
- Will H&E staining work for TAI?
- If not, what kind of stain will work?
- No.
- Have to do a silver stain.
Fill in the blanks.
