Stroke

Question 1

What is a stroke? What’s difference between stroke and transient ischaemic attack?

Answer 1

A stroke is a neurological defect (loss of function), of sudden onset which lasts >24hrs and has a vascular origin

Transient ischaemic attack (TIA) <24hrs

Question 2

How does a stroke cause neuronal damage?

Answer 2

Due to electrical failure in the brain OR lack of oxygen —> anaerobic metabolism —> lactic acidosis

Question 3

What is a completed stroke?

Answer 3

Prolonged hypoxia becomes anoxia (no oxygen) which results in infarction (complete cell death)
Further damage may result in an oedema or a secondary haemorrhage into the stroke

Question 4

What is the ischaemic cascade?

Answer 4

Without adequate blood supply (inadequate oxygen & glucose) brain cells lose ability to produce energy
Cells switch to anaerobic metabolism (less ATP and lactic acid - disrupts normal acid-base balance = cell death)
ATP ion transport pumps fail so membrane depolarised —> excess calcium and potassium —> activation of proteases + lipases —> excitotoxicity (formation of free radicals)
Cells are broken down releasing toxins poisoning nearby neurons
Breakdown of blood-brain barrier —> cerebral oedema

Question 5

Why do strokes happen?

Answer 5

Strokes happen due to a blocked or ruptured blood vessel in the brain causing failure of neuronal function leading (usually) to some deficit in brain function

Question 6

What are some of the causes of strokes (4)?

Answer 6

Blockage with thrombus or clot (85-90%)
- clot/thrombus stops blood supply to area of brain
Disease of vessel wall
Disturbance of normal properties of blood
Rupture of vessel wall (Haemorrhage) (10-15%)
- blood leaks into brain tissue

Question 7

What causes brain infarctions (heart causes (4) & vessel causes (4))?

Answer 7

Heart:
- Left ventricle thrombi
- Valve disease 
- Cardiogenic emboli
- Atrial fibrilation
 Vessel:
- Flow reducing carotid stenosis 
- Carotid plaque with arteriogenic emboli
- Penetrating artery disease
- Intracranial atherosclerosis

Question 8

What are the subtypes of stroke (4)?

Answer 8

1. Arteriolar cerebral artery (ACA) occlusion:
   
   • paralysis and sensory loss of contra-lateral foot and leg
   • impairment of gait and stance
2. Middle cerebral artery (MCA):
   
   • contra-lateral paralysis and sensory impairment of face/arm/leg
   • contralateral hemianopia (loss of visual field)
   • aphasia (trouble speaking)
3. Small vessel (lacunar) stroke (LACS):
   
   • devoid of other cortisol signs
   • either purely motor, sensory or dysarthria (clumsy hand)
   • uncoordination
4. Posterior circulation stroke (POCS):
   
   • coma, vertigo, nausea, vomiting, uncoordination

Question 9

What does the FAST campaign stand for?

Answer 9

o	Face – has face fallen on one side
	- Can they still smile
o	Arms – can they raise both arms and keep them there
o	Speech – is their speech slurred
o	Time – time to call 999
	- If any of the signs are seen

Question 10

What are the normal palpable pulses (5)

Answer 10

Aorta
Common femoral 
Popliteal
Posterior tibial
Dorsal is pedis

Question 11

What is critical limb ischaemia?

Answer 11

Atherosclerotic disease of the arteries supplying the lower limb

Question 12

What are the 4 stages of the Fontaine classification of critical limb ischaemia?

Answer 12

Stage 1:
	- Asymptomatic 
	- Incomplete blood vessel obstruction
Stage 2:
	- Mild claudication pain in limb 
Stage 2A:
	- Claudication when walking a distance of greater than 200m
Stage 2B:
	- Claudication when walking a distance of less than 200m
Stage 3:
	- Rest pain, mostly in the feet
Stage 4:
	- Necrosis and/or gangrene of the limb

Question 13

What is acute limb ischaemia?

Answer 13

Formed by either an embolus or thrombus leading to sudden decrease in blood flow that threatens the viability of the limb

Question 14

What is compartment syndrome?

Answer 14

Muscle ischaemia which leads to inflammation, oedema and venous obstruction (irreversible after 6-8hrs)