Stroke

Question 1

What is a stroke?

Answer 1

A neurological deficit (‘loss of function’) of sudden onset, lasting <24 hours, of vascular origin (TIA - lasts <24 hours).

Question 2

What is a haemorrhagic stroke?

Answer 2

A rupture of a vessel wall in the brain.
Blood leaks into brain tissue (15%).
Causes a greater % of death than ischaemia.

Question 3

What is an ischaemic stroke?

Answer 3

A blockage of a vessel wall in the brain.
Clots/thrombi stop blood supply (85%).

Question 4

What are the causes of brain infarctions?

Answer 4

Carotid stenosis (at the bifurcation).
Atrial fibrillation (the most common cause of cardioembolic strokes).
Cardiogenic emboli.

Question 5

What are the different types of stroke prevention?

Answer 5

Primary - treatment of individuals with no history of stroke.
Secondary - treatment of individuals who have already had a stroke or TIA.

Question 6

What are the risk factors of stroke?

Answer 6

Hypertension (lacunar or haemorrhage).
Diabetes (cardioembolic).
Smoking (ischaemic).
Cholesterol, alcohol, obesity, age, AF, hypercoagulability.

Question 7

What are the causes of ischaemic stroke?

Answer 7

Idiopathic.
Cardiac embolism.
Lacunar disease.
CVD.

Question 8

What are the causes of ischaemic stroke?

Answer 8

Hypertension.
Alcohol abuse.
Hypocholesterolaemia.

Question 9

What are comorbid conditions associated with stroke?

Answer 9

Diabetes.
Pulmonary disease.
Acute MI.
Cancer.
Renal disease.
PVD.

Question 10

What is the pathophysiology of stroke?

Answer 10

If hypoxia is prolonged, it becomes anoxia.
This results in infarction, cell death, and necrosis (a complete stroke).

Question 11

How can oedema affect the severity of stroke?

Answer 11

Depends on the size, location, or secondary haemorrhages of the stroke.

Question 12

How is lactic acid produced in the ischaemic cascade?

Answer 12

ATP production decreases.
Cells undergo anaerobic metabolism.
Lactic acid is released and destroys cells, by disrupting the acid-base balance of the brain.

Question 13

How is excitotoxicity caused in the ischaemic cascade?

Answer 13

ATP transporters fail.
Ca2+ moves into cells, causing glutamate release. Excess Ca2+ entry activates enzymes, causing excitotoxicity.
The cell membrane and mitochondria are broken down, releasing toxins.

Question 14

How does cerebral oedema occur in the ischaemic cascade?

Answer 14

Cells undergo apoptosis and are necrosed, releasing glutamate and toxins.
The blood-brain barrier is broken down.
Cerebral oedema causes secondary progression of brain injury.

Question 15

What do the carotid and vertebro-basilar system supply in the brain?

Answer 15

Carotid - most of the hemispheres and cortical deep white matter.
Vertebro-basilar - brain stem, cerebellum, occipital lobes.

Question 16

What are the symptoms of a stroke?

Answer 16

Clumsy or weak limbs.
Ataxia, nystagmus, loss of sensation, vertigo.
Dysarthria and dysphasia.
Visuospatial problems, loss of vision in one eye.
Hemianopia.

Question 17

What are the symptoms of anterior cerebral artery occlusion?

Answer 17

Paralysis of the contralateral leg and foot.
Sensory loss over the contralateral leg, foot and toes.
Impairment of gait and stance.

Question 18

What are the symptoms of middle cerebral artery occlusion?

Answer 18

Paralysis of the contralateral face, arm and leg.
Sensory loss of the contralateral side.
Contralateral homonymous hemianopia.
Contralateral gaze paralysis.
Aphasia (if stroke on the dominant (left) side).
Unilateral neglect for half of the external space (if non-dominant stroke, usually the right side).

Question 19

What are the symptoms of a lacunar stroke?

Answer 19

No ‘cortical’ signs (dysphasia, neglect, hemianopia).
Pure motor or sensory stroke.
Dysarthria.
Ataxic hemiparesis.

Question 20

What are the symptoms of posterior circulation?

Answer 20

Involves the brain stem, cerebellum, thalamus, and parts of the occipital and temporal lobes.

Coma, drop attacks, vertigo, nausea, vomiting, cranial nerve palsies, ataxia, hemiparesis, hemisensory loss.

Question 21

What are the subtypes of stroke?

Answer 21

TACS - total anterior circulation stroke (whole of MCA).
PACS - partial anterior circulation stroke (part of MCA).
LACS - lacunar stroke.
POCS - posterior circulation stroke.

Question 22

What is the importance of stroke?

Answer 22

1/3rd of patients will die within 1yr of stroke onset.
50% of survivors remain dependent on others.
Accounts for more hospital and nursing home bed-days than any other condition.
Costs society ~£9 billion a year.
Affects informal care the most.

Question 23

What are the characteristics of patients with ischaemic stroke?

Answer 23

~75yrs old.
F>M.
At admission - can talk, orientate themselves, and lift both arms.

Question 24

What is the treatment for stroke?

Answer 24

Thrombolysis - time-dependent.
Acute stroke triage.
PUFFINS - potential use of fast field cycling mRI in stroke.
Clot retrieval.

Question 25

What is acute stroke therapy?

Answer 25

Restoration of blood supply (non-toxic).
Prevention of extensive ischaemic damage.
Protection of vulnerable brain tissue.
Avoidance of reperfusion injury.