Stroke: Ischaemic Stroke

Question 1

Definition

Answer 1

Rapid onset of neurological deficit
- lasting for more than 24 hours
- poor blood flow to brain causes cell death

Question 2

Epidemiology

Answer 2

Older people
Males

Question 3

Risk factors

Answer 3

Hypertension: the single greatest risk factor
Age: the average age for a stroke is 68 to 75 years old
Smoking
Diabetes
Hypercholesterolaemia
Atrial fibrillation
Family history
Haematological disease: such as polycythaemia
Medication: such as hormone replacement therapy or the combined oral contraceptive pill

Question 4

Aetiology

Answer 4

Reduction in cerebral blood flow due to arterial occlusion or stenosis.
- Cardiac:
=Atherosclerotic disease: smoking, hypertension , diabetes , high cholesterol
= Atrial fibrillation
= Paradoxical embolism due to septal abnormality, such as a patent foramen ovale
- Vascular
= Aortic dissection
=Vertebral dissection
= Vasculitides
- Haematological
= Hypercoagulability, such as antiphospholipid syndrome
= Sickle cell disease
= Polycythaemia

Question 5

Pathophysiology

Answer 5

Reduction in cerebral blood flow due to arterial occlusion or stenosis. Typically divided into thrombotic, embolic and lacunar.
Blood vessel to/in brain occluded by a clot
Ischaemia + infarction follow
- Infarcted areas dies, resulting in focal neurological symptoms
- Infarcted area is surrounded by a swollen area (oedema) which can regain function with neurological recovery

Question 6

ACA Signs

Answer 6

If ACA:
- Contralateral Hemiparesis + sensory loss (lower limbs more than upper limbs)
- Akinetic Mutism (will not speak or move, no motivation to do so)

Question 7

MCA Signs

Answer 7

• Contralateral hemiparesis and sensory loss with upper limbs > lower limbs
• Contralateral Homonymous hemianopia
• DOMINANT SIDE = APHASIA:
  Wernicke’s Aphasia (aka receptive aphasia) = cannot understand speech (posterior superior temporal lobe)
  Broca’s Aphasia (aka Expressive Aphasia) = cannot produce speech (left inferior frontal gyrus)
• NON DOMINANT = APRAXIA AND HEMINEGLECT SYNDROME
  Apraxia = patient can move muscles to do stuff, but don’t know how to
  Hemineglect syndrome = all visual and sensory sensations on the contralateral side is neglected
  E.g. if the left MCA is affected, the left optic radiations will be affected so the right visual field will be lost = right homonymous hemianopia.

Question 8

PCA signs

Answer 8

Visual problems
- Homonymous hemianopia with macula sparring (as the MCA can still supply the region of the occipital lobe which is responsible for the macular)
- Visual agnosia (patient can see but not interpret symbols e.g. letters)

Question 9

Vertebrobasilar

Answer 9

Cerebellar signs
Reduced consciousness
Quadriplegia (paralysis of all 4 limbs - arms and legs) or hemiplegia

Question 10

Weber’s syndrome (branches of the posterior cerebral artery that supply the midbrain)

Answer 10

• Ipsilateral CN III palsy
• Contralateral weakness of upper and lower extremity

Question 11

Anterior inferior cerebellar artery (lateral pontine syndrome)

Answer 11

• Symptoms are similar to Wallenberg’s but:
• Ipsilateral: facial paralysis and deafness

Question 12

Posterior inferior cerebellar artery (lateral medullary syndrome, Wallenberg syndrome)

Answer 12

• Ipsilateral: facial pain and temperature loss
• Contralateral: limb/torso pain and temperature loss
• Ataxia, nystagmus

Question 13

Retinal/ophthalmic artery

Answer 13

Amaurosis fugax

Question 14

Basilar artery

Answer 14

Locked in syndrome

Question 15

Lacunar stroke

Answer 15

Affects the small perforating branches to subcortical structures (e.g. internal capsule, basal ganglia, thalamus, pons)
- Present with either isolated hemiparesis, hemisensory loss or hemiparesis with limb ataxia
- Strong association with HTN

Question 16

Investigations

Answer 16

FIRST LINE = Non-contrast CT head
- Exclude haemorrhage
- Low density in gray + white matter
- Hyperdense artery sign

ECG = atrial fibrillation
Bloods tests =
- Glucose to rule out hypoglycaemia
CT angiogram (CTA): identifies arterial occlusion and should be performed in all patients who are appropriate for thrombectomy
MRI head: higher sensitivity for infarction than CT

Question 17

Management

Answer 17

FIRST LINE = Antiplatelet = Aspirin 300mg
- If treated with thrombolysis, start aspirin after 24 hours once haemorrhage is excluded
- continue until 2 weeks after the onset of stroke symptoms
Thrombolysis: If < 4.5 hours of symptoms onset and haemorrhage excluded on imaging = IV ALTEPLASE
SECONDARY PREVENTION =
- Clopidogrel 75mg daily lifelong is first line (after 2 weeks of aspirin 300mg)
- High dose statin: ATORVASTATIN 20-80mg usually 48 hours of the stroke

Question 18

Thombectomy protocol

Answer 18

Offer thrombectomy as soon as possible and within 6 hours of symptom onset, together with intravenous thrombolysis (if within 4.5 hours), to people who have:
acute ischaemic stroke and
confirmed occlusion of the proximal anterior circulation demonstrated by computed tomographic angiography (CTA) or magnetic resonance angiography (MRA)

Offer thrombectomy as soon as possible to people who were last known to be well between 6 hours and 24 hours previously (including wake-up strokes):
confirmed occlusion of the proximal anterior circulation demonstrated by CTA or MRA and
if there is the potential to salvage brain tissue, as shown by imaging such as CT perfusion or diffusion-weighted MRI sequences showing limited infarct core volume

Question 19

Complications

Answer 19

Deep vein thrombosis: due to immobility
Aspiration pneumonia: due to dysphagia
Neurological sequelae: such as weakness, impaired mobility, MCA syndrome and seizures
Requirement for nutritional support: such as nasojejunal feeding
Depression