RESPONSES TO THE BRAIN IN TRAUMATIC INJURY

Question 1

What is the tentorium?

Answer 1

a tough connective tissue that separates the hemispheres of the brain from the brainstem and cerebellum

Question 2

how do we measure the severity of a brain injury?

Answer 2

glasgow coma scale
post traumatic amnesia
loss of consciousness

Question 3

what does it mean if a lesion is extra-axial?

Answer 3

within skull but outside brain parenchyma

Question 4

what are intra-axial lesions?

Answer 4

lesions within the brain parenchyma

Question 5

what is a coup injury?

Answer 5

brain damage that occurs directly under the point of impact

Question 6

what is a countrecoup injury?

Answer 6

occurs on the opposite side of the brain from where the head is struck

Question 7

what are some symptoms of brain injury?

Answer 7

vomiting, pain, dizziness, loss of consciousness, amnesia

Question 8

outline the natural history of a brain injury?co

Answer 8

primary brain injury
progressive damage
secondary injury
functional outcome

Question 9

what are some focal brain injuries?

Answer 9

contusion, haemorrhage, skull fracture, penetrating jead injury

Question 10

what are some examples of progressive damage in the brain after primary injury?

Answer 10

mechanoporation
calcium flux
oxygen free radical formation
lipid peroxidation
axotomy

Question 11

how is cerebral blood flow usully autoregulated?

Answer 11

through vasoconstriction and vasodilation

Question 12

how are intercranial haemorrhages initially compensated for?

Answer 12

venous constriction and absorption of CSF into the spinal cord

Question 13

what is the monro-kellie doctrine?

Answer 13

the sum of volumes of brain, CSF, and intracranial blood is constant so an increase in 1 means a decrease in the others

Question 14

what is raised ICP?

Answer 14

> 20mmhg

Question 15

what is severe ICP increase?

Answer 15

> 40mmHg

Question 16

what are the 4 stages of increasing ICP?

Answer 16

Stage 1 - compensatory reduction in CSF and blood volume so no rise in ICP

stage 2 - when volune continues to increase beyond the point of compensation, the ICP increases
‣ may feel drowsy and have a headache

stage 3 - sustained increased ICP with dramatic changes in ICP and small changes in volume, decreasing cerebral perfusion pressure
‣ deteriorating conscious level, intermittent elevations in bp and bradycardia

stage 4 - cerebral perfusion pressure caeses, widespread necrosis begins and compression of brainstem respiratory centres lead to respiratory arrest and death
‣ coma, fixed dilated pupils, death

Question 17

outline the volume pressure curve during raised ICP?

Answer 17

As haematoma volume increases, initially the ICP doesnt rise but pass the point of decompensation we get exponential rise in ICP
the time from pont of decompensation and herniation is relatively small compared to haematoma growing time so you must treat urgently!

Question 18

what are some symptoms and signs of raised ICP?

Answer 18

headache
vomiting without nausea
ocular palsies
altered level of consciousness
back pain
papilloedema

Question 19

what is Cushing’s reflex?

Answer 19

if ICP rises, the body responds by releasing endogenous steroids and mean blood pressure will increase which is impprtant to maintain cerebral perfusion pressure

Question 20

whats the equation for the cerebral perfusion pressure?

Answer 20

mean blood pressure - intercranial pressure

Question 21

what do extradural haematomas look like on CT?

Answer 21

white lens shape

Question 22

what does a subdural haematoma look like on CT?

Answer 22

bi-convex shape

Question 23

whats a craniotomy?

Answer 23

taking a patch of bone off the skull and removing the blood causing pressure