brain blood supply and CVA

Question 1

when does a stroke occur?

Answer 1

when blood flow to part or whole brain is interrupted

Question 2

what arteries join to form the arterial circle of Willis?

Answer 2

branches of the internal carotid and basilar artery

Question 3

what substances move freely across the blood-brain barrier?

Answer 3

blood, gases, water, alcohol, anesthetics

Question 4

can amino acids and glucose readily cross the blood-brain barrier?

Answer 4

no, require carrier protein

Question 5

what is a stroke?

Answer 5

a focal neurological impairment of sudden onset and lasting more than 24hrs and of presumed vascular origin

Question 6

what occurs to the portion of the brain that has died after CVA?

Answer 6

undergoes liquefactive necrosis

Question 7

what happens due to cerebrovascular accidents?

Answer 7

tissue which has died because blood supply has failed and is infarcted

Question 8

what are some risk factors for CVA?

Answer 8

• increasing age
• smoking
• heart disease
• atherosclerosis
• hypertension

Question 9

what is an ischaemic stroke caused by?

Answer 9

occlusion of blood flow

Question 10

what could an occlusive (ischaemic) stroke be due to?

Answer 10

• thrombosis
• embolism
• shock

Question 11

what is thrombosis?

Answer 11

obstruction of a blood vessel by a blood clot forming locally

Question 12

what is thrombosis usually from?

Answer 12

usually atherosclerosis with thrombus forming around atherosclerosis plaque

Question 13

what is thrombosis often associated with?

Answer 13

hypertension and diabetes mellitus

Question 14

what is an embolism?

Answer 14

obstruction due to blood clot from elsewhere in the body, usually the heart itself

Question 15

what are the two major zones of injury within the ischaemic area?

Answer 15

core ischaemic zone and ischaemic penumbra

Question 16

what can severe ischemia within the core zone result in?

Answer 16

necrosis of neurons and also supporting cellular elements

Question 17

what is penumbra?

Answer 17

the rim of mild to moderate ischaemic tissue between tissue that is normally perfused and the area of severe ischemia

Question 18

what are the two types of oedema in and around infarcted tissue?

Answer 18

cytotoxic and vasogenic

Question 19

how long does cytotoxic oedema last?

Answer 19

mins to hours

Question 20

how long does vasogenic oedema last?

Answer 20

hours to days

Question 21

what is cytotoxic oedema?

Answer 21

swelling of all cellular elements of affected area

Question 22

what is vasogenic oedema?

Answer 22

increase in ISF volume due to increased permeability of small vessels

Question 23

when does cerebral oedema peak during stroke?

Answer 23

2-5 days after

Question 24

what is the recovery of function after stroke largely due to?

Answer 24

resorption of oedema fluid

Question 25

when does herniation occur?

Answer 25

occurs when the pressure inside the skull increases and displaces brain tissue

Question 26

why can brain herniation rapidly lead to death?

Answer 26

due to compression of blood vessels and of structures such as respiratory centres

Question 27

where may bleeding occur in hemorrhagic stroke?

Answer 27

within brain and within surrounding meningeal spaces

Question 28

what are some features that present in hemorrhagic stroke?

Answer 28

raised intracranial pressure such as nausea, vomiting, and headache

Question 29

what is intracerebral hemorrhage usually due to?

Answer 29

- hypertensive damage - rupture of aneurysm or arteriovenous malformation - necrosis due to tumor/infection - venous outflow obstruction

Question 30

what deep tissue structures are commonly affected by intracerebral hemorrhage?

Answer 30

- basal ganglia - thalamus - cerebellum - pons and other brainstem sites

Question 31

what does focal mean?

Answer 31

related to a specific region

Question 32

what are the key features of an acute stroke?

Answer 32

sudden onset and presence of focal neurological symptoms

Question 33

what are some symptoms of an acute stroke?

Answer 33

- altered consciousness - headache - aphasia - facial weakness - ataxia - visual loss

Question 34

what does aphasia mean?

Answer 34

incoherent speech or difficulty understanding speech

Question 35

what does ataxia mean?

Answer 35

poor balance, clumsiness or difficulty walking

Question 36

what are some common patterns that occur in the left dominant hemisphere during stroke?

Answer 36

- aphasia - right hemiparesis - right-sided sensory loss - difficulty reading, writing or calculating

Question 37

what are some common patterns that occur in the right hemisphere during stroke?

Answer 37

- neglect of left field - extinction of left-sided stimuli - left hemiparesis - spatial disorientation

Question 38

what are some common patterns that occur in the brainstem, cerebellum, and posterior hemisphere during stroke?

Answer 38

- motor/sensory loss in all limbs - crossed signs - amnesia - bilateral field defects - dysconjugate gaze

Question 39

what are some common patterns that occur in the small subcortical hemisphere or brain stem during (pure motor) stroke?

Answer 39

weakness of face/limbs on one side of body without abnormalities of higher brain function, motor function or vision

Question 40

what is a closed head injury?

Answer 40

skull remains intact

Question 41

what may a closed head injury be due to?

Answer 41

damage due to external indirect force (blunt trauma) or internal pathological process

Question 42

what can closed head injuries cause?

Answer 42

diffuse axonal injury or focal injury

Question 43

what is an open head injury?

Answer 43

the skull is penetrated and the brain is damaged by direct force

Question 44

what is an open head injury generally caused by?

Answer 44

penetrating trauma- break in dura mater

Question 45

what may open head injuries cause?

Answer 45

focal injury

Question 46

what is the primary cause of head injury?

Answer 46

caused by impact and can include acceleration, deceleration, or direct impact/injury

Question 47

what can secondary head injury cause?

Answer 47

- cerebral oedema - hematoma - infection - increased intracranial pressure

Question 48

what can tertiary head injury cause?

Answer 48

- aponea - hypotension - respiratory and cardiovascular effects of primary/secondary injuries

Question 49

what goes the Glasgow Coma Scale assess?

Answer 49

severity score from 3 (worst) to 15 (best)

Question 50

what are some therapy tools for brain damage?

Answer 50

- oxygen (ventilation) - steroids - diuretics

Question 51

what is post-traumatic amnesia?

Answer 51

loss of memory around time of trauma