Traumatic Brain Injury Flashcards
What group does TMI mainly affect
Young adults
Leading cause of death <45 years
What % of patients with head injury have long term disabiltiy
50
What is the thinnest part of the skull
Pterion
What runs under the pterion
Middle mesangial artery
What is a space occupying lesion
Something extra in cranial cavity like blood/ swelling
How may space occupying lesion be compensated for
- CSF into the spine
- Venous blood into circulation
What is the intracranial pressure in a compensated state
ICP is normal
At what point does ICP begin to rise
Point of decompensation
What does cerebral perfusion pressure=
=Mean Arterial Pressure- Intracranial pressure
Why does it matter when ICP increases
Most other organs perfused with blood at mean arterial pressure
As ICP increases, effective perfusion pressure in the brain decreases
What happens with CPP falls
Cerebral blood flow falls
Apart from decreasing cerebral blood flow, what else does ICP cause
Herniation of the brain outside of the skull
What are Duret Haemorrhages
Small lineages of blood in midbrain and pons caused by traumatic downward displacement of brainstem
What are the 2 layers of the dura mater called
Outer= periosteal Inner= meningeal
What is the munro-kelly doctrine hypothesis
Volume inside cranium is fixed
Cranium cannot be compressed
Box and its contents are in equilibrium
What molecular changes occur in the brain after injury (4)
- Axons break and separate forming retraction balls
- Neurons undergo apoptosis
- Loss of energy and ion metabolism of injured cells
- Cytotoxic oedema: injured cells swell up
What is meant by neuroprotectipn
Therapy aimed at preventing neuronal cell death after injury with effect of improving outcome
Define coma
Inability to open eyes, vocalise words and obey simple commands
How does coma affect respiration and circulation (4)
Depresses cough, gag and swallow
Slows ventilation
Decreases BP
Adequate perfusion of oxygenated blood vital
Where do epidural bleeds happen
Above the dura- between cranium and the dura mater
When do epidural bleeds happen
Can happen as result of damage at pterion
Arterial bleeds
Where do subdural bleeds happen
Between dura mater and arachnoid mater
When do subdural bleeds happen
Damage to bridging veins that cross subdural space
Where do subarachnoid bleeds happen
Between arachnoid and pia mater
