ischaemic stroke overview

ISCHAEMIC STROKE

INTRODUCTION• The blood supply is blocked

by a blood clot or clump of fat. This damages your brain cells and they begin to die.

• Ischaemic stroke affects about 9 out of every 10 people who have a stroke. It’s most common in people over the age of 65, although can happen at any age.

TWO TYPES

ARTERIAL THROMBOSIS

• Also called thrombotic stroke or cerebral thrombosis.

• This is when a blood clot forms in an artery that supplies your brain and blocks the blood supply.

TWO TYPES (cont’d)

CEREBRAL EMBOLISM

• Also known as embolic stroke. • This is when a blood clot

forms somewhere else in your body and travels to your brain and blocks the blood supply. The clot usually forms in your heart or one of the large arteries that supplies your brain.

RISK FACTORS

NON-MODIFIABLE RISK FACTORS

• Age

• Gender

• Race, Ethnicity

• Heredity

RISK FACTORS (cont’d)

MODIFIABLE RISK FACTORS• Hypertension• Cardiac Disease• Diabetes Mellitus• Smoking• Alcohol• Cholesterol• Illicit Drug Use• Migraines

RISK FACTORS (cont’d)

MODIFIABLE RISK FACTORS• Oral Contraceptives• Haemostatic and

Inflammatory Factors.• Hyperhomocysteinemia• Asymptomatic Carotid

Stenosis• Transient Ischemic Attacks• Lifestyle Factors (Obesity,

Physical Activity, Diet, and Acute Triggers).

SIGNS & SYMPTOMS

• Symptoms usually come on suddenly, within seconds or minutes.

• You may also have a Transient Ischaemic Attack (TIA) before a full blown stroke.

SIGNS & SYMPTOMS (cont’d)

• A good way to recognise if you or someone you’re with has had a stroke is to use the ‘FAST’ test.

SIGNS & SYMPTOMS (cont’d)• The exact symptoms

depend on where in your brain the blood supply has been blocked.

• This is because different areas of your brain control different functions and they all receive blood through different arteries.


TRANSIENT ISCHAEMIC ATTACK (TIA)

• A transient neurologic attack that lasts <24 hours (most last <1 hour) and is determined to be of ischaemic etiology.


ANTERIOR CEREBRAL ARTERY

• Contralateral paresis and sensory loss in the leg.

• Cognitive or personality changes.


MIDDLE CEREBRAL ARTERY

• Pneumonic: “CHANGes”– Contralateral paresis and

sensory loss in the face and the arm.

– Homonymous Hemianopsia.– Aphasia.– Neglect.– Gaze preference toward the

side of the lesion.


POSTERIOR CEREBRAL ARTERY

• Pneumonic: The 4 D’s

– Diplopia

– Dizziness

– Dysphagia

– Dysarthria


BASAL GANGLIA LACUNAR

• Pure motor or sensory stroke.

• Dysarthria-clumsy hand syndrome, ataxic hemiparesis.


BASILAR ARTERY

• Coma• “Locked-In” Syndrome• Cranial Nerve Palsies• Apnea• Visual Symptoms• Drop Attacks• Dysphagia• Dysarthria• Vertigo• “Crossed” weakness and sensory loss

affecting the ipsilateral face and contralateral body.

DIAGNOSIS

• You will have your blood pressure measured and an electrocardiogram (ECG) to record the rhythm and electrical activity of your heart.

• Echocardiogram (ECHO) of your heart if embolic stroke is suspected.

• You may then have tests to measure the levels of cholesterol and sugar in your blood.

DIAGNOSIS (cont’d)• As soon as possible you’ll

also have a brain scan, such as a CT or MRI. This will determine whether you have had an ischaemic stroke or a haemorrhagic stroke. A haemorrhagic stroke is when an artery or vein bursts and bleeds into your brain.

• Strokes <6 hours old are usually NOT visible on CT scan.

DIAGNOSIS (cont’d)

• White signals on left side are suggestive of blockage of blood flow in Left side blood vessel (MCA) suggestive of acute brain attack (infarction).

• Diffusion-weighted MRI is sensitive for acute stroke with changes as early as 20 minutes after an ischaemic event.

DIAGNOSIS (cont’d)• MRI of acute middle carotid artery

(MCA) stroke on MRI at 12 hours post-ictus. T2-weighted image shows mild hyper-intensity of the middle carotid artery territory (arrows). Non-contrast T1-weighted image demonstrates early stroke changes with effacement of cortical sulci in the MCA territory associated with swelling and mild hypo-intensity of the cortical ribbon (arrows). After contrast (gadolinium) administration, intravascular enhancement is present, indicating sluggish flow in the ischemic zone (arrows).


• MRI axial FLAIR images of Brain show an infarct involving left frontal lobe anterior to sylvian fissure. Area of involvement corresponds to left MCA Superior Division territory.


• Left: CT scan slice of the brain showing a right-hemispheric ischemic stroke.

• Right: MRI showing damaged brain cells due to a left-hemispheric ischaemic stroke.


VASCULAR STUDIES

• Carotid Ultrasound

• Transcranial Doppler

• MRA (Magnetic Resonance Angiography)

• CT Angiography

• Conventional Angiography


LABORATORY STUDIES• Complete blood count (CBC)• Basic chemistry panel• Coagulation studies• Toxicology screening: May assist in

identifying intoxicated patients with symptoms/behaviour mimicking stroke syndromes.

• Arterial blood gas analysis: In selected patients with suspected hypoxemia. It defines the severity of hypoxemia and may be used to detect acid-base disturbances.

TREATMENT

TREATMENT (cont’d)

• If you can't swallow, you’ll be given fluid through a drip in your arm to stop you becoming dehydrated.

• You will have a nasogastric tube inserted to give you all the nutrients and medicines that you need.

• You may also be given oxygen through a face mask or by means of endotracheal intubation to help maintain optimum blood oxygen saturation levels.


• You’ll be helped to sit up and encouraged to move around as soon as you’re able.

• If you can’t move, your healthcare team will regularly help you to turn in your bed. This will reduce your risk of getting bed sores and deep vein thrombosis (DVT).

• You may also be given a mechanical pump to use on your feet and legs. This is called an intermittent compression device. The pump automatically squeezes your feet and lower legs to help your blood circulate.


MEDICINES• Alteplase is a medicine (IV

tPA-Tissue Plasminogen Activator) used to break up blood clots, and will help restore the blood flow to your brain. You need to have it within four and a half hours of your symptoms starting for it to be effective.

• Intra-arterial thrombolysis can be used within 6 hours of a major stroke from Middle Cerebral Artery occlusion if such patients are not suitable candidates for Alteplase.

CONTRAINDICATIONS TO ALTEPLASE THERAPY

Pneumonic: SAMPLE STAGES

– Stroke or head trauma within the last 3 months.

– Anticoagulation with INR>1.7 or prolonged PTT.

– MI (recent).– Prior Intracranial

Haemorrhage.– Low Platelet Count

(<100,000/mm3 )– Elevated BP: Systolic>185 or

Diastolic >110mmHg

– Surgery in the past 14 days.– TIA (mild symptoms or rapid

improvement of symptoms). – Age<18– GI or urinary bleeding in the

past 21 days – Elevated (>400mg/dl) or

Decreased (<50mg/dl) Blood glucose.

– Seizures present at the onset of stroke.


MEDICINES• Aspirin and Clopidogrel are

used to reduce your risk of blood clots forming after a stroke.

• Aspirin is associated with reduced morbidity and mortality in acute ischaemic stroke presenting <48 hours from onset.

• Warfarin, non-vitamin K antagonist oral anticoagulant medicines (NOACs) or Heparin can also prevent blood clots forming. You may have these medicines if your doctor thinks the clot came from your heart. Again, these aren’t suitable for everybody.

• You may also be given some other medicines to control your blood pressure, blood sugar and lower your cholesterol.


SURGERY• This may involve an

operation called Carotid Endarterectomy to remove blood clots and fatty deposits from one of the carotid arteries in your neck. The surgery may help to reduce your risk of having another stroke but isn’t suitable for everyone.


CAROTID ENDARTERECTOMY

• If stenosis is >70% in symptomatic patients or >60% in asymptomatic patients (Contraindicated on 100% occlusion).


• Monitor for signs and symptoms of brain swelling, ↑ICP and herniation.

• Serial CTs are helpful in the evaluation of deteriorating patients.

• As a temporizing measure, treat with Mannitol and hyperventilation.

TREATMENT (cont’d)SEVERE HYPERTENSION (SYSTOLIC

BP>220 OR DIASTOLIC BP>120mmHg)

• Treat with IV Labetalol or Nicardipine infusion.

• For the administration of Alteplase, the patient’s systolic BP must be <185 and diastolic BP<110mmHg.


• Treat: Fever and Hyperglycaemia, as both are associated with worse prognoses in the setting of acute stroke.

• Prevent and treat post-stroke complications: Aspiration Pneumonia, UTI and DVT.

COMPLICATIONS

REHABILITATION• A multidisciplinary team of health

professionals will work out a rehabilitation programme for you that’s designed around your particular needs.

• Rehabilitation aims to help you stay as independent as possible and get back to your usual activities, or adapt to new ways of doing things.

• You may make most of your recovery in the early weeks and months afterwards but you may continue to improve for years.

REHABILITATION (cont’d)

PROGNOSIS

• In the acute phase of stroke, the strongest predictors of outcome are : Stroke Severity and Patient Age.

• Stroke severity can be judged clinically, based upon the degree of neurologic impairment and the size and location of the infarction on neuroimaging with MRI or CT.

• Other important influences on stroke outcome include infarct location, ischemic stroke mechanism, comorbid conditions, epidemiologic factors, and complications of stroke.

• In the period from 12 hours to 7 days after ischemic stroke onset, many patients who are without complications experience moderate but steady improvement in neurologic impairments. The greatest proportion of recovery occurs in the first 3 to 6 months after stroke, with lesser improvements thereafter.

PROGNOSIS (cont’d)

• The return of arm and hand function after stroke is particularly important to a good functional recovery. Early active finger extension, grasp release, shoulder shrug, shoulder abduction, and active range of motion are associated with a favourable prognosis for arm and hand recovery at 6 months.

ischaemic stroke overview

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