Chapter 10- Raised Intracranial Pressure

Front 1

what is Intracranial pressure?

Back 1

the pressure within the skull

Front 2

what are the determinant of the Intracranial pressure

Back 2

brain- 78%
blood- 12%
CSF- 10%

Front 3

what is the normal level of ICP

Back 3

7-15mmhg- supine

standing its negative

Front 4

what is raised ICP called

Back 4

intracranial hypertension

Front 5

Name 4 causes of raised intracranial pressure

Back 5

Many Eggs Crack Outside

Mass lesions
Edema
CSF disturbance
Obstruction in venous sinuses

Front 6

describe mass lesions

Back 6

hematoma- epi, subdural, intracranial, hemorrhage (hypertension), abscess, tumors

Front 7

describe edema

Back 7

can be focal- due to trauma or diffuse- due to encephalitis, meningitis or head injury

Front 8

describe CSF disturbances

Back 8

obstruction of CSF flow within ventricles or at tis exits- foramen magendie or luschka

or communicating hydrocephalus- with subarachnoid space and other ventricles

Front 9

what is the reason for ventricular obstruction

Back 9

aqueductal stenosis

Front 10

why does communicating hydrocephalus develop

Back 10

with impaired CSF resorption, excess CSF flows through adhesions in the subarachnoid space left by meningitis or dysfunctional pachionian granulations

Front 11

what is the cause for venous obstruction in the brain

Back 11

cerebral venous thrombosis

Front 12

can there be benign intracranial hypertension

Back 12

yes, its idiopathic

Front 13

what is monro kelpie hypothesis

Back 13

volume within the cranium is fixed

Front 14

what are the principle buffer systems of the cranium for pressure

Back 14

CSF and blood

Front 15

where is csf displaced to

Back 15

spinal canal

venous system via arachnoid villi

Front 16

what happens to the blood

Back 16

reduced volume of it in the veins and dural sinuses

Front 17

what is the effect of increased ICP on blood supple

Back 17

it reduces it

Front 18

why is the blood supply worsened

Back 18

because of the equation

Front 19

describe CEREBRAL PERFUSION PRESSURE equation

Back 19

CPP= Mean arterial pressure - ICP

Front 20

what is the CPP range

Back 20

70-90

Front 21

what happens when there is a decrease of cerebral perfusion pressure

Back 21

dilation of cerebral vessels to keep more blood

Front 22

what happens when there is dilation of vessels and therefore more blood in the brain

Back 22

icnrease in cerebral volume which lead to increased ICP

Front 23

what happens to untreated to ICP

Back 23

ischemia and then infarction

Front 24

what are the clinical symptoms

Back 24

headache- diffuse
vomiting
apathy
papillodema
cushings triad

Front 25

what are the symptoms of increased ICP in infants with unclosed sutures

Back 25

drowsiness,
inhibition
loss of appetite
vomiting
bulging fontanelle
big head

Front 26

what is the main consequence of advanced increased ICP

Back 26

herniation- coning

Front 27

what is the cause of uncal transtentorial herniation- laterally

Back 27

temporal lobe enlargement

Front 28

what could be causes of temporal lobe enlargement of compression leading to uncal transtentorial herniation

Back 28

hematoma- subdural- epidural
unilateral supratentorial masses in the temporal lobe

Front 29

what passes through the tentorial notch in uncal transtentorial herniation?

Back 29

inferomedial part of the ipsilateral temporal lobe

Front 30

what CN is affected in the uncal transtentorial herniation

Back 30

CN3----> mydriasis
no pupillary light reflex

Front 31

what are the motor effects of uncal transtentorial herniation

Back 31

depression of cerebral peduncles leads to contralateral hemiparesis

Front 32

what are the effects on consciousness of uncal transtentorial herniation

Back 32

depression of ARAS lead to loss of it

Front 33

what are the visual effects of uncal transtentorial herniation and why

Back 33

compression of posterior cerebral artery leads to loss of contralateral visual field- contralateral homonymous hemianopsia because of infarction of occipital lobe

Front 34

what type of posturing may be seen in uncal transtentorial herniation

Back 34

decerebrate

Front 35

what are the end stage findings of uncal transtentorial herniation

Back 35

damage to cardio-respiratory centres due to tonsillar herniation

Front 36

why do central transtentorial herniation happen

Back 36

lesions in the midline from the frontal lobe through to the occipital lobe

Front 37

what is displaced through the tentorial notch by the central transtentorial herniation

Back 37

diencephalon and midbrain

Front 38

what vascular and mechanical changes happen as a result of central transtentorial herniation

Back 38

damage to vessels lead to DURETS haemorrhage and then infarct

there is mechanical distortion

Front 39

what ar the symptoms of central transtentorial herniation

Back 39

loss of consciousness

bilateral babinski

decorticate and later decerebrate posture

Front 40

what are the end stage findings of central transtentorial herniation

Back 40

tonsillar herniation and its implications

Front 41

where do lesions occur to cause infratentorial herniation

Back 41

around the cerebellum

Front 42

what movement do you see in infratentorial herniation

Back 42

upwards- brain tissue

downwards- cerebellar tonsils

Front 43

in tonsillar herniation what tissue moves where

Back 43

cerebellar tonsil move into the foramen magnum

Front 44

what causes subfalcine herniation

Back 44

unilateral supratentorial masses

Front 45

what are unilateral supratentorial masses

Back 45

tumors, hemorrhage, edema

Front 46

how does a subfalcine herniation happen

Back 46

the masses push the brain to the opposite side, pushing the cingulate gyrus below the falx cerebri

Front 47

what are he clinical signs of subfalcine herniation

Back 47

none

Front 48

what are the basic treatments of increased ICP

Back 48

elevation of head- 30deg
breath well- o2 and co2
eat well- glycemia
rest
control fever

Front 49

why should blood oxygen etc be controlled what are their effects on vessels

Back 49

low o2 leads to cerebral vessel dilation

Front 50

how are seizure avoided in inc ICP

Back 50

give anticonvulsants

Front 51

what can be given to counter agitation and pain

Back 51

analgesia- fentanyl

sedation- propofol, diazepam

Front 52

what osmotic drugs can be given to inc ICP patients

Back 52

mannitol -20%
saline-3%

Front 53

how can ventilation be manipulated for treatment of inc ICP

Back 53

hyperventilation--> hypocapnia--> vessel constriction

Front 54

what drug can be given WITH mannitol

Back 54

furosemide

Front 55

what drug is useful to treat inc ICP caused by tumours and meningitis

Back 55

glucocorticoids

Front 56

what is the last resort in treatment of inc ICP

Back 56

craniectomy

and barbiturate coma

Front 57

what are dangers of barbiturate coma and what can be used with it

Back 57

hypotension, vasopressors to reduce hypotension

Front 58

example of barbiturae

Back 58

pentobarbital