Stroke & TIA

Question 1

Why do brain cells and neurons die during a stroke/TIA

Answer 1

Hypoxia and lack of glucose for ATP production

Question 3

What is a stroke

Answer 3

A sudden neurological deficit caused by an interruption of blood to the brain, resulting in brain cell damage due to ischaemia or haemorrhage

Question 4

What can cause an ischaemic stroke

Answer 4

Thrombus-clot forms in artery already narrowed by atherosclerosis

Embolus-clot travels from elsewhere (AF/DVT)

Systemic - gross reason for decrease in blood flow (Cardiac arrest, MI, shock)

Question 5

Risk factors for ischaemic strokes

Answer 5

Hypertension
AF
Diabetes
Smoking
Hyperlipidaemia
Obesity
Previous TIA/Stroke

Question 6

Anterior cerebral artery

Answer 6

Major artery in the brain that supplies oxygenated blood to the frontal lobe, parietal lobe and corpus callosum

Question 7

Causes of haemorrhagic stroke

Answer 7

Long standing hypertension

Cerebral aneurysm rupture

Anticoagulant use

Head trauma

Question 8

Why do some strokes cause leg weakness but not arm weakness

Answer 8

Leg weakness is indicative of a midline stroke, arm weakness occurs when the stroke is more lateral.

Question 9

What is midline shift

Answer 9

Displacement of brain structures across the midline when there is raised intracranial pressure

Question 10

Middle cerebral artery

Answer 10

supplies oxygenated blood to the brain’s parietal and temporal lobes and deeper parts.

Question 11

Posterior cerebral artery

Answer 11

Supplies oxygenated blood to the occipital lobe and brainstem

Question 12

Posterior communicating artery

Answer 12

connects brains anterior and posterior circulations, providing blood to the brain and allowing for collateral circulation

Question 13

What is collateral circulation/ circle of willis

Answer 13

network of backup vessels that can take over when another artery or vein is damaged or blocked

protects against ischaemic injury from conditions like coronary atherosclerosis, PAD

Question 14

Test for posterior strokes

Answer 14

A-Ataxia
V-Vertigo
V-Vomiting
V-Visual disturbances

Question 15

Where do TIA usually occur

Answer 15

Circle of Willis

Question 16

Ischaemic Stroke Development Pathophysiology

Answer 16

Reduced blood flow = cells do not receive glucose and oxygen

Build up of sodium and calcium.

Sodium = swelling (cytotoxic oedema). Damage to mitochondria and lysosomes = release of apoptosis factors and degradative enzymes

Immune cell activation = inflammation = damage to BBB = proteins and fluids into brain tissue = swelling (vasogenic oedema)

pressure to unaffected side (cingulate herniation). Can also push to the base of the skull (cerebellar tonsil herniation) = affecting breathing and consciousness

Question 17

What symptoms might happen during an anterior or middle cerebral artery stroke

Answer 17

Numbness
Sudden muscle weakness

Question 18

If a stroke occurs in Broca’s or Wernicke’s area, what symptoms can occur & where are these parts

Answer 18

Broca’s (L Frontal)- Slurred speech

Wernicke’s (L Temporal)- Difficulty understanding speech

Question 19

Penumbra

Answer 19

Blood supply is inhibited to a part of the brain an ischaemic core of cells can develop and die (tissue necrosis)

surrounding these cells is the penumbra (viable cells)

severed by collateral circulation. Can die if circulation is not re-established within 1-2 hours

Question 20

Haemorrhagic stroke definition

Answer 20

Blood vessel ruptures = bleeding in or around the brain.
Disrupts normal blood flow = direct damage to brain tissues and increasing ICP

Question 21

Intracerebral Haemorrhage
Subarachnoid Haemorrhage

Answer 21

ICH: Bleeding occurs within brain

SAH: Bleeding occurs in the space between inner and outer layers of tissue that surround the brain

Question 22

Haemorrhagic stroke development (pathophysiology)

Answer 22

ICH- Hypertension
SAH - aneurysm burst or trauma

blood leaks into brain cells = raised ICP

Any vessels downstream of the pressure are starved of blood = ischaemia

pressure can cause brain herniation

Question 23

Falx Cerebri
Tentorium Cerebelli
Foramen Mangnum

Answer 23

FC: Sickle shaped fold of dura mater that separated the two cerebral hemispheres

TC: Invagination of the meningeal layer of the dura mater that separates the occipital and temporal lobes of the cerebral hemispheres from the cerebellum and brainstem

FM: Large opening in the skull that connects the brain to the spinal cord

Question 24

Cushing’s Triad

Answer 24

Response to increased intracranial pressure when the nervous system attempts to compensate for diminished cerebral perfusion,

Hypertension
Bradycardia
Irregular Respirations

Question 25

Cushing's Triad: Hypertension

Answer 25

Sympathetic nervous system activated to maintain cerebral perfusion

Question 26

Cushing's Triad: bradycardia

Answer 26

Increased systolic BP activates the parasympathetic nervous system to slow HR

Question 27

Cushing's Triad: Irregular Respirations

Answer 27

Increased ICP can put pressure on the brainstem = dysfunction of respiratory centre (medulla)

Question 28

Differentiation of ischaemic v haemorrhagic stroke

Answer 28

Ischaemic: usually caused by atherosclerosis, prolonged aetiology, long history of vessel disease, may be associated with heart conditions, PMH of angina or previous strokes Haemorrhagic: usually the result of cerebral aneurysm, sudden aetiology, commonly develops during exercise or high stress, associated with cocaine use, may be asymptomatic prior to rupture

Question 29

What is a TIA

Answer 29

Cerebral ischaemia that does not inflict any permanent damage/ Typical stroke symptoms - rarely last longer than 2 hours Should only be considered if there is a complete resolution of symptoms

Question 30

Stroke Vs TIA

Answer 30

Stroke: effects can be irreversible, life threatening, life altering, ischaemic cells post 5 min die, cavitation in the brain can occur as a result of necrosis TIA: Temporary occlusion o the vessel, intermittent short symptoms. precursor for stroke

Question 31

Hospital Treatment for Stroke

Answer 31

Thrombolytic Enzymes - activate body's clot busting mechanisms Aspirin - Prevents more clots Surgery - physically remove clot

Question 32

How do the following increase the risk of a stroke Smoking Cocaine use Hypertension

Answer 32

Smoking: Smoking decreases HDL and promotes platelet adhesion and causes vasoconstriction Cocaine use: increases BP and causes cardiac arrythmias Hypertension: causes endothelium damage

Question 33

General stroke symptoms

Answer 33

Facial drooping Unilateral limb weakness Aphasia or dysphasia Aphagia or dysphagia Fitting Incontinence Visual disturbance Confusion Fear Unequal pupils Abnormal gait Loss of balance Unexplained falls Ataxia Vomiting

Question 34

Stroke Mimics

Answer 34

Hypoglycaemia Hypoxia Hypotension Hypothermia Fitting Toxins, sedatives or alcohol Bells palsy

Question 35

What is bell's palsy and what can cause it

Answer 35

Damage to the 7th cranial nerve infection, haemorrhage, local trauma, meningitis, tumour