Principles and Cerebrovascular Disease

Question 1

What is the dura?

Answer 1

the tough fibrous outer layer which bridges crevices and is attached to the skull

Question 2

What is the arachnoid?

Answer 2

delicate sealed bag for CSF - bridges crevices - impermeable to salt and water

Question 3

What ropes across the subarachnoid space?

Answer 3

arachnoid trabeculae

Question 4

Where is the cerebral artery branch?

Answer 4

embedded in the pia - susceptible to tearing and damage

Question 5

What is the pia mater?

Answer 5

delicate - next to brain and dips into crevices

Question 6

What are the main cellular components of the CNS?

Answer 6

nerve cells
glial cells
blood vessels
microglia
connective tissue - meninges

Question 7

What are the glial cells?

Answer 7

astrocytes, oligodendrocytes, ependyma

Question 8

What can damage the cells of the CNS?

Answer 8

hypoxia
trauma
toxic insult
metabolic abnormalities
nutritional deficiencies
infections
ageing
genetic abnormalities

Question 9

What are the neuronal responses to injury?

Answer 9

acute neuronal injury
simple neuronal atrophy
sub-cellular alterations
axonal reactions

Question 10

Why are neurons particularly susceptible to hypoxic damage?

Answer 10

due to activation of glutamate receptors -> Ca overload

can’t use anaerobic glycolysis

Question 11

Why would you be better drowning in cold water?

Answer 11

slows metabolic processes and cell death down

Question 12

What is the axonal reaction?

Answer 12

the reaction within the cell body that is associated with injury to the axon

Question 13

What is the responses to axonal injury?

Answer 13

• increased RNA and protein synthesis
• swelling of the cell body
• peripheral displacement of the nucleus
• enlargement of the nucleolus
• anterograde degeneration of the axon - distal to site of injury
• breakdown of myelin sheat

Question 14

How do astrocytes react to injury?

Answer 14

proliferation (gliosis)

reactions leading to cell death or degeneration

Question 15

What is the process gliosis?

Answer 15

where astrocytes undergo hyperplasia and hypertrophy
nucleus is enlarged, becoming vesicular and the nucleolus is prominent
cytoplamsic expansion with extension of ramifying processes

Question 16

What can be seen on old lesions of gliosis?

Answer 16

nuclei become small and dark and lie in a dense net of processes - fibrils
comparable to scar formation

Question 17

What is injury to oligodendrocytes a feature of?

Answer 17

demyelinating diseases

Question 18

How do oligodendrocytes react to injury?

Answer 18

very limited response

Question 19

where are ependymal cells found?

Answer 19

lining the ventricular system

Question 20

What is disruption of ependymal cells associated with?

Answer 20

local proliferation of sub-ependymal astrocytes producing small irregularities on the ventricular surfaces - ependymal granulations

Question 21

What can produce changes in ependymal cells?

Answer 21

infectious agents i.e. viruses

Question 22

How do microglia respond to injury?

Answer 22

• proliferate
• develop elongated nuclei
• forming aggregates about small foci of tissue necrosis
• congregate around portions of dying neurons

Question 23

How long does brain need to lose blood supply before there is irreversible damage?

Answer 23

4 minutes

Question 24

How much CO and O2 does the brain receive?

Answer 24

15% of CO and 20% of O2

Question 25

How is blood flow maintained in the brain?

Answer 25

autoregulatory mechanisms

Question 26

Where does the blood supply in the brain come from?

Answer 26

internal carotid arteries and vertebral arteries

Question 27

Why is the circle of willis protective?

Answer 27

occlusion of any one pathway does not stop flow to one area unlike when blood flow is deeper into the brain

Question 28

Where is the circle of willis?

Answer 28

base of the brain

Question 29

What does occlusion to the anterior cerebral artery lead to?

Answer 29

contralateral sensory loss in foot and leg | paresis of arm and foot, relative sparing of thigh and face

Question 30

Where does the anterior cerebral artery lead?

Answer 30

frontal lobe

Question 31

What happens with occlusion to the middle cerebral artery?

Answer 31

hemiparesis hemisensory loss aphasia/dysphasia - loss of language or vocal chord function apraxia

Question 32

what does the brain stem consist of?

Answer 32

mid-brain, pons, medulla

Question 33

What does the brain stem control?

Answer 33

cardio-respiratory centres

Question 34

what do bleeds on the occipital lobe cause?

Answer 34

homonymous hemianopia because of the cross over of optic nerve

Question 35

What does a stroke in the cerebellum cause?

Answer 35

ataxia nystagmous - eye twitch in extreme visual fields intention tremor pendular reflexes - acts like a pendulum when it shouldnt

Question 36

what is the mortality of Cerebrovascular disease?

Answer 36

20% in the first month

Question 37

What are the potential causes of cerebrovascular disease?

Answer 37

brain ischemia and infarctions haemorrhages vascular malformations and developmental abnormalities

Question 38

What may cause hypoxic ischemic damage?

Answer 38

respiratory obstruction, lung and heart disease, epilepsy, cardiac arrest

Question 39

Which groups of neurons are more vulnerable to hypoxic/ischemic damage?

Answer 39

pyramidal cells of hippocampus | purkinje cells of cerebellum

Question 40

What are watershed areas?

Answer 40

junctions of arteries which are the first areas to be deprived

Question 41

When may hypoxic ischemic encephalopathy occur?

Answer 41

in any circumstance that results in global decrease in HbO2 available to the brain

Question 42

What is a stroke?

Answer 42

a sudden disturbance of cerebral function of vascular origin that causes death or lasts over 24 hours

Question 43

What are the types of stroke and their commonality?

Answer 43

infarction (84%) or haemorrhage (16%)

Question 44

What is a cerebral infarction?

Answer 44

caused by local interuption of cerebral blood flow due to thrombosis or emboli

Question 45

What is an embolis?

Answer 45

a clot that has broken off

Question 46

What are risk factors for stroke?

Answer 46

atheroma, HBP, serum lipids, obesity, diet, T2DM, heart disease, smoking

Question 47

What is the morphology of a cerebral infarct 4-12 hours later?

Answer 47

brain may appear normal

Question 48

What is the morphology of a cerebral infarct 15-20 hours later?

Answer 48

ischemic neuronal changes develop

Question 49

What is the morphology of a cerebral infarct 24-36 hours later?

Answer 49

inflammatory reaction, extravasion of RBCs and activation of astrocytes and microglia

Question 50

What is the morphology of a cerebral infarct 36-48 hours later?

Answer 50

necrotic area visible macroscopically, becomes swollen and softer than surrounding tissue

Question 51

What is the morphology of a cerebral infarct 3 days later?

Answer 51

macrophages are in the area

Question 52

What is the morphology of a cerebral infarct 1-2 weeks later?

Answer 52

liquification of tissue and gliosis

Question 53

What is the morphology of a cerebral infarct months later?

Answer 53

cavitation and completion of glial scar

Question 54

What is the most common cause of haemorrhage?

Answer 54

spontaneous

Question 55

What is a spontaneous haemorrhage??

Answer 55

rupture of a saccular aneurysm

Question 56

Where do most aneurysms occur?

Answer 56

arise at arterial bifurcation in territory or internal carotid (90%)

Question 57

What are the potential morphologies of aneurysms?

Answer 57

- rupture of berry aneurysm - bleeds into subarachnoid space - intracerebral haematomas adjacent to aneurysm - infarcts of brain parenchymal due to arterial spasms (40%)

Question 58

What are the clinical features of haemorrhages?

Answer 58

-abrupt onset (headache, vomiting, loss of conciousness)

Question 59

What are the signs of a haemorrhage?

Answer 59

bloody CSF, meningeal signs incl. neck stiffness

Question 60

What are the complications of a haemorrhage?

Answer 60

cerebral infarcts, acute hydrocephalus, herniation

Question 61

Why may chronic hydrocephalus develop in patients surviving the initial haemorrhage?

Answer 61

due to organisation of blood in the leptomeninges and or arachnoid granulations with resultant obstruction of CSF flow

Question 62

What does hypertension cause in the brain?

Answer 62

increased atheroma hyaline arteriosclerosis microaneurysms shift in autoregulatory curve to the right

Question 63

What is the pathology of hypertension in the brain?

Answer 63

- lacunar infarcts - intracerebral haemorrhage - multi-infarct dementia - hypertensive encephalopathy