Ischaemic Stroke

Question 1

What is a stroke?

Answer 1

A cerebrovascular event (stroke) is a clinical syndrome caused by disruption of blood supply to the brain, characterised by rapidly developing signs of focal or global disturbance of cerebral functions, lasting for more than 24 hours or leading to death.

Question 2

What are the main types of stroke?

Answer 2

A stroke results either from ischaemic infarction of part of the brain or from intracerebral haemorrhage.

The two main types of stroke are not reliably distinguishable clinically but pointers include:

• Haemorrhagic stroke: meningism, severe headache and coma within hours.
• Ischaemic stroke: carotid bruit, atrial fibrillation, past TIA.

Question 3

What is the aetiology of ischaemic infarction?

Answer 3

Ischaemic infarction may be caused by atheroma or thromboembolism and, more rarely, by trauma, infection or tumours.

Question 4

What is the aetiology of stroke in a young px?

Answer 4

Vasculitis.
Thrombophilia.
Subarachnoid haemorrhage.
Venous sinus thrombosis.
Carotid artery dissection - e.g., via near-strangling or fibromuscular dysplasia.

Question 5

What is the aetiology of stroke in a older px?

Answer 5

Thrombosis in situ.
Athero-thromboembolism - e.g., from carotid arteries.
Heart emboli (particularly associated with atrial fibrillation, infective endocarditis or myocardial infarction).
Central nervous system (CNS) bleed (associated with hypertension, head injury, aneurysm rupture).
Sudden blood pressure drop by more than 40 mm Hg.
Vasculitis - e.g., giant cell arteritis.
Venous sinus thrombosis.

Question 6

What are the risk factors for stroke?

Answer 6

Hypertension.
Smoking.
Diabetes mellitus.
Heart disease (valvular, ischaemic, atrial fibrillation).
Peripheral arterial disease.
Post-TIA (TIAs are associated with a high early risk of stroke) 
Polycythaemia vera.
Carotid artery occlusion; carotid bruit.
Combined oral contraceptive pill.
Hyperlipidaemia.
Excess alcohol.
Clotting disorders.

Question 7

How does stroke present?

Answer 7

Either sudden onset or a step-wise progression of symptoms and signs over hours (or even days) is typical.

In people with sudden onset of neurological symptoms, a validated tool, such as FAST (Face, Arm, Speech, Time to call 999/112/911), should be used outside hospital to screen for a diagnosis of stroke or TIA.

Focal signs relate to distribution of the affected artery but collateral supplies may cause variation in the presentation.

Question 8

How does cerebral hemisphere infarcts present?

Answer 8

Contralateral hemiplegia which is initially flaccid (floppy limb, falls like a dead weight when lifted) and then becomes spastic.
Contralateral sensory loss.
Homonymous hemianopia.
Dysphasia.
Higher cognitive impairment

Question 9

How does posterior circulation ischaemia present?

Answer 9

Motor deficits (weakness, clumsiness, or paralysis of any combination of arms and legs, up to quadriplegia, sometimes changing from one side to another in different attacks).

‘Crossed’ syndromes: ipsilateral cranial nerve dysfunction and contralateral long motor or sensory tract dysfunction.

Sensory deficits: numbness, including loss of sensation or paraesthesia in any combination of extremities, sometimes including all four limbs or both sides of the face or mouth.
Homonymous hemianopia.
Ataxia, imbalance, unsteadiness, or disequilibrium.
Vertigo, with or without nausea and vomiting.
Diplopia (ophthalmoplegia).
Dysphagia or dysarthria.
Isolated reduced level of consciousness can result from bilateral thalamic or brain stem ischaemia.

Question 10

What is the locked-in syndrome?

Answer 10

Complete infarction affecting the pons causes ‘locked-in syndrome’ with quadriparesis, loss of speech, but preserved awareness and cognition, and sometimes preserved eye movements.

Question 11

How does lacunar infarcts present?

Answer 11

Small infarcts around the basal ganglia, internal capsule, thalamus and pons.
May cause pure motor, pure sensory, or mixed motor and sensory signs, or ataxia.
Intact cognition/consciousness.

Question 12

What are the differentials of stroke?

Answer 12

Always exclude hypoglycaemia as a cause of sudden-onset neurological symptoms.
TIA in the first 24 hours of the stroke.
Brain tumour.
Subdural haematoma.
Todd’s palsy.
Consider acute poisoning if the patient is comatose.

Question 13

What are the investigations for stroke?

Answer 13

FBC - thrombocytopenia, polycythaemia.
Test for sickle cell disease.
Erythrocyte sedimentation rate (ESR) - giant cell arteritis (consider temporal lobe artery biopsy, start steroids).
Check blood pressure
Emboli from the left atrium may have caused the stroke. Look for a large left atrium on CXR and consider echocardiography.
Brain imaging should be undertaken as soon as possible (and within 24 hours or symptom onset) in all patients.
Imaging with CT contrast angiography should also be performed if thrombectomy might be indicated.
Carotid duplex ultrasound: in stroke or TIA in carotid territory.

Question 14

What are the indications for brain imaging with non-enhanced CT in a px with a suspected stroke?

Answer 14

Has indications for thrombolysis or early anticoagulant treatment.

Is currently taking anticoagulant treatment.

Has a known bleeding tendency.

Has a depressed level of consciousness (Glasgow Coma Score below 13).

Has unexplained progressive or fluctuating symptoms.

Has papilledema, neck stiffness or fever.

Has severe headache at onset of stroke symptoms.

Question 15

What is the management of acute stroke?

Answer 15

Patients should be admitted to hospital (ideally a specialist acute stroke unit for initial care and treatment, unless the diagnosis will make no difference to management - e.g., where the optimal management is palliative care).
Maintenance or restoration of homeostasis
People with acute stroke should have their swallowing screened before being given any oral food, fluid or medication. Also screen for malnutrition.
Antiplatelet therapy
Thrombolytic treatment
Drugs depressing the function of the CNS (e.g., anxiolytics and tranquilisers) and new prescriptions for sedatives should be avoided.
Do not start statin treatment immediately after an acute stroke but continue statin treatment for people with acute stroke who are already taking statins.
Encourage the person to sit out of bed and mobilise as soon as their clinical condition permits, as part of an active management programme.
High-intensity mobilisation should not be offered in the first 24 hours to people who need help to sit out of bed, stand or walk.
Patients with TIA, or patients with a stroke who have made a good recovery when seen, should be assessed and investigated in a specialist service (e.g., a neurovascular clinic) as soon as possible and within seven days of the incident.

Question 16

What is involved in the maintenance of restoration of homeostasis in a stroke patient?

Answer 16

Oxygen therapy; give supplemental oxygen only if oxygen saturation drops below 95%.

Blood sugar control; maintain blood glucose concentration between 4 and 11 mmol/L. Provide optimal insulin therapy with intravenous insulin and glucose, for people with diabetes.

Blood pressure control:

• Blood pressure reduction to 185/110 mm Hg or lower should be considered in people who are candidates for intravenous thrombolysis.
• For people with acute intracerebral haemorrhage who present within six hours and have a systolic blood pressure of 150-220 mm Hg (unless there is a structural cause for the haemorrhage or they have a poor expected prognosis or Glasgow Coma Scale score of below 6), offer rapid blood pressure lowering, aiming for systolic pressure of 130-140 mm Hg maintained for at least seven days

Question 17

When should you offer antihypertensives to a stroke patient?

Answer 17

Give antihypertensive treatment only if there is a hypertensive emergency with one or more of the following:

• Hypertensive encephalopathy.
• Hypertensive nephropathy.
• Hypertensive cardiac failure/ myocardial infarction.
• Aortic dissection.
• Pre-eclampsia/eclampsia.
• Intracerebral haemorrhage with systolic blood pressure >200 mm Hg.

Question 18

What is the anti platelet therapy offered to stroke patient?

Answer 18

Aspirin 300 mg daily, unless contra-indicated, should be offered to people who have had a suspected TIA, and started immediately.

Aspirin (300 mg) should be given as soon as possible after the onset of stroke symptoms once a diagnosis of primary haemorrhage has been excluded.

For long-term vascular prevention in people with ischaemic stroke or TIA without paroxysmal or permanent atrial fibrillation:

• Clopidogrel 75 mg daily should be the standard antithrombotic treatment.
• Aspirin 75 mg daily with modified-release dipyridamole 200 mg twice daily should be used for those who are unable to tolerate clopidogrel:
• Aspirin 75 mg daily should be used if both clopidogrel and modified-release dipyridamole are contra-indicated or not tolerated.
• Modified-release dipyridamole 200 mg twice daily should be used if both clopidogrel and aspirin are contra-indicated or not tolerated.

Question 19

What is the thrombolytic treatment for stroke?

Answer 19

Unless there are contra-indications, thrombolytic treatment appears to be effective in improving prognosis after an acute stroke.
Treatment with alteplase should only be given provided that:
-It is administered within four and a half hours (preferably within three hours) of onset of stroke symptoms.
-Haemorrhage has been definitively excluded.
-There is immediate access to imaging and re-imaging, including staff trained to interpret the results.

Question 20

What is the surgical treatment for stroke?

Answer 20

Thrombectomy should be offered as soon as possible (and within six hours of symptom onset) to patients with confirmed ischaemic stroke with occlusion of the proximal anterior circulation and if there is potential to salvage brain tissue. Can be considered up to 24 hours after symptom onset in specific situations (see your notes)

Surgical intervention should be considered in cases of supratentorial haemorrhage with mass effect or posterior fossa/cerebellar haematoma.

Neurosurgical opinion should be sought for cases of secondary hydrocephalus.

Carotid endarterectomy

Consider referring for surgical decompressive hemicraniectomy (performed within 48 hours of symptom onset) if middle cerebral artery (MCA) infarction is present and all the following are met:

• Clinical deficits suggestive of infarction in the territory of the MCA.
• Score of above 15 on the NIHSS.
• Decrease in the level of consciousness.
• Signs on CT scan of an infarct of at least 50% of MCA territory with infarct volume greater than 145 cm3 as shown on diffusion-weighted MRI.

Question 21

When is thrombectomy considered in stroke patients?

Answer 21

Thrombectomy should usually only be considered in patients with:

• A pre-stroke functional status of less than 3 on the modified Rankin scale; and
• A score of more than 5 on the National Institutes of Health Stroke Scale NIHSS)

Question 22

What is involved in stroke rehabilitation?

Answer 22

People with acute stroke should be helped to sit out of bed, stand or walk as soon as their clinical condition permits as part of an active management programme in a specialist stroke unit. However, if they need help to perform these activities, they should not be offered high-intensity mobilisation within the first 24 hours after onset of symptoms.

High-intensity mobilisation:

• Begins within 24 hours of onset of symptoms.
• Includes at least three more out-of-bed sessions than usual care.
• Focuses on sitting, standing and walking.

Interventions for visual defects, memory problems, emotional functioning, dysphagia, communication difficulties, motor problems, pain, return to work issues, self-care

A full medical assessment should be undertaken on all people with stroke, including cognition (attention, memory, spatial awareness, apraxia, perception), vision, hearing, tone, strength, sensation and balance.

On admission to hospital, any person with stroke should be screened and, if problems are identified, management started as soon as possible for the following: orientation, positioning, moving and handling, swallowing, transfers (e.g., from bed to chair), pressure area risk, continence, communication, nutritional status and hydration.

Question 23

What are the complications of stroke?

Answer 23

Neurological problems: balance, movement, tone and sensation.
Pain: neuropathic and/or musculoskeletal.
Depression, anxiety, emotionalism, disturbed social interaction, disinhibition, aggression.
Cognitive impairments: attention and concentration, memory, disturbances of spatial awareness, disturbance of perception (e.g., visual agnosia), apraxia and disturbances of executive functioning (planning, organising, initiating and monitoring behaviour).
Speech and communication difficulties: dysphasia, dysarthria, and apraxia of speech.
Visual impairments and hemianopia.
Bladder and bowel problems: urinary incontinence, faecal incontinence, constipation.
Swallowing problems, poor oral health, malnutrition, dehydration.
Sexual dysfunction .
Difficulties with activities of daily living: personal, social and vocational.
Other complications include thromboembolism, pneumonia and bedsores
Dysphagia affects a large proportion of stroke patients. Swallowing difficulties can result in reduced fluid and food intake, and cause aspiration, which can lead to aspiration pneumonia, undernutrition and dehydration.

Question 24

What is the prognostic score used for people with TIA?

Answer 24

Total scores range from 0 (low risk) to 7 (high risk):
Age (1 point where aged 60 years or over).
Blood pressure (1 point for blood pressure of 140/90 mm Hg, or higher).
Clinical features (2 points for unilateral weakness; 1 point for speech disturbance without weakness).
Duration of symptoms (2 points for 60 minutes or longer; 1 point for 10-59 minutes).
-1 point is added for the presence of diabetes.

People who have had a suspected TIA who are at high risk of stroke (i.e. an ABCD score of 4 or above) should have aspirin (300 mg daily) started immediately, specialist assessment and investigation within 24 hours of onset of symptoms and measures for secondary prevention introduced as soon as the diagnosis is confirmed, including discussion of individual risk factors.