ischaemic stroke

Question 1

define ischaemic stroke

Answer 1

a clot blocks blood flow to an area of the brain

neurological dysfunction due to ischaemia and death of brain, spinal cord, or retinal tissue following vascular occlusion or stenosis.

Question 2

define haemorrhagic stroke

Answer 2

bleeding occurs inside or around brain tissue

neurological dysfunction caused by a focal collection of blood from rupture of a blood vessel within the brain (intracerebral haemorrhagic stroke) or between the surface of the brain and the arachnoid tissues covering the brain (subarachnoid haemorrhagic stroke).

Question 3

define ischaemia

Answer 3

• insufficient blood flow to the brain to meet metabolic demand
• This leads to poor oxygen supply or cerebral hypoxia, and may in turn lead to the death of brain tissue or cerebral infarction
• Ischaemia may be reversible
• Infarction is irreversible

Question 4

pathway from ischaemia to infarction

Answer 4

Tissue hypoperfusion
- Dysfunction

Early & reversible failure of the Na+ K+ pump
- Some cellular oedema

Progressive failure Na+ K+ pump until an irreversible ‘tipping point’ is reached
- Sudden influx Na+ ions
Cytotoxic oedema

BBB opens for macromolecules
- Vasogenic oedema

BBB opens for RBC’s
- Haemorrhage into the infarct

Question 5

define TIA

Answer 5

A brief episode of neurological dysfunction caused by focal brain and/or retinal ischaemia, with clinical symptoms typically lasting < 1 hour, and without evidence of acute infarction

Question 6

what are the ages of a infarct

Answer 6

Hyperacute (1st 6 hours)
late hyperacute (6 to 24 hours)
Acute (up to 7 days)
Subacute (up to 4 months)
Chronic (after 4 months)

Question 7

treatment for hyperacute infarct

Answer 7

The only approved therapy is intravenous thrombolysis with Alteplase within 4.5 hours of onset of stroke symptoms

Thrombolysis may not be given until haemorrhage has been excluded

Question 8

Ix for stroke

Answer 8

unenhanced CT - highly sensitive for the detection of acute haemorrhage

FBC, U&Es, glucose, ESR, lipid profile
ECG
CXR
CT head scan
consider doppler USS of carotids
CT is sensitive to the detection of stroke mimics e.g. tumour, arterial venous malformation (AVM) that could be the cause of the neurological defect

Question 9

signs of cerebral infarct on CT

Answer 9

• Hypoattenuating
• Cortical-sub cortical
• Within a vascular territory

Question 10

role of unenhanced CT

Answer 10

• Eliminate haemorrhage as a cause as itll preclude thrombolysis
• look for any early features of ischaemia
• exclude other intracranila pathologies that may mimc a stroke and determine further investigations
• May show a target - thrombosed vessel
• Identify infarctions that are too big, too old for thrombolysis (increased risk of haemorrhage) - based on hyppattenuation

Question 11

role of MRI

Answer 11

Detection and diagnosis of acute infarction
- Diffusion weighted imaging
- Positive from 2 hours to 3 weeks
- Useful
----- Previous CVD makes CT difficult
----- Difficult location for CT - posterior fossa
------ Equivocal case - query tumour?
------ Sensitivity - TIA clinic
MRA and MRV

Question 12

Immediate recognition of stroke done by which tools

Answer 12

outside of hospital - FAST

Exclude hypoglycaemia in people with sudden onset of neurological symptoms as the cause of these symptoms.

at ED use ROSIER

Question 13

criteria to do CT

Answer 13

immediately at least within one hour

indications for thrombolysis or thrombectomy
on anticoagulant treatment
a known bleeding tendency
a depressed level of consciousness (GCS below 13)
unexplained progressive or fluctuating symptoms
papilloedema, neck stiffness or fever
severe headache at onset of stroke symptoms

thrombectomy might be indicated, perform imaging with CT contrast angiography following initial non-enhanced CT. Add CT perfusion imaging (or MR equivalent) if thrombectomy might be indicated beyond 6 hours of symptom onset.

Question 14

oxygen therapy and sugar control

Answer 14

give oxygen only if their sats drop below 95%

maintain blood glucose between 4 and 11 mmol.l

Question 15

who to offer thrombectomy

Answer 15

within 6 hours of symptom onset plus IV thrombolysis

• acute ischaemia stroke
• confirmed occlusion of the proximal anterior circulation demonstrated by CTA or MRA

last known to be well between 6 hours and 24 hours previously (including wake-up strokes):

• who have acute ischaemic stroke and 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 16

Tx foe cerebral venous sinus thrombosis

Answer 16

full-dose anticoagulation treatment (initially full-dose heparin and then warfarin [INR 2 to 3]

Question 17

when do you give BP medications

Answer 17

• hypertensive encephalopathy
• hypertensive nephropathy
• hypertensive cardiac failure/myocardial infarction
• aortic dissection
• pre-eclampsia/eclampsia.

Blood pressure reduction to 185/110 mmHg or lower should be considered in people who are candidates for intravenous thrombolysis.

attempt to reduce it after 2 weeks

Question 18

earliest CT sign

Answer 18

hyperdense segment of a vessel which needs to be differentiated from a calcified cerebral embolus

Question 19

most commonly affected vessel in stroke

Answer 19

middle cerebral artery

Question 20

early hyperacute signs on CT

Answer 20

loss of grey-white matter differentiation, and hypoattenuation of deep nuclei

cortical hypodensity with associated parenchymal swelling with resultant gyral effacement

Question 21

acute signs on CT

Answer 21

With time the hypoattenuation and swelling become more marked resulting in a significant mass effect. This is a major cause of secondary damage in large infarcts.

Question 22

subacute signs on CT

Answer 22

As time goes on the swelling starts to subside and small amounts of cortical petechial haemorrhages result in elevation of the attenuation of the cortex. This is known as the CT fogging phenomenon 5.

Imaging a stroke at this time can be misleading as the affected cortex will appear near normal.

contrast CT or MRI will show you wrong

Question 23

old infarct how does it look

Answer 23

well demarcated

very low density similar looking to CSF

negative mass effect

Question 24

old infarct how does it look

Answer 24

well demarcated

very low density similar looking to CSF

negative mass effect

Question 25

role of CT angiography

Answer 25

may identify thrombus within an intracranial vessel, and may guide intra-arterial thrombolysis or clot retrieval

Question 26

what is a time attenuation curve

Answer 26

As contrast passes through the brain it causes a transient hyperattenuation directly proportional to the amount of contrast in the vessels of that region

Question 27

how do you calculate cerebral blood flow

Answer 27

cerebral blood volume divide mean transit time

Question 28

reduction in the CBV represents what

Answer 28

irreversible infarction

Question 29

what can u use to distinguish ischaemia from infarction

Answer 29

CBF and CBV maps

Question 30

if you have a large core infarct and do thrombolysis what risk does it increase

Answer 30

secondary haemorrhage

Question 31

causes of ischaemic stroke

Answer 31

occluded by thrombus ((often as a complication of atherosclerosis) Embolus of fatty material from an atherosclerotic plaque or a clot in a larger artery or the heart (often as a complication of atrial fibrillation or atherosclerosis of the carotid arteries).

Question 32

causes of haemorrhagic stroke

Answer 32

Intracerebral haemorrhage – bleeding within the brain parenchyma or ventricular system. The main cause of intracerebral haemorrhage is high blood pressure. Subarachnoid haemorrhage – bleeding into the subarachnoid space from a cerebral blood vessel, aneurysm or vascular malformation.

Question 33

rarer causes of stroke

Answer 33

Cerebral venous thrombosis — more likely in patients with a prothrombotic tendency, for example, related to pregnancy, infection, dehydration or malignancy. Carotid artery dissection — tends to occur in younger people and may be preceded by neck trauma.

Question 34

risk factors of stroke

Answer 34

``` age men COCP Cardiovascular disease such as angina, myocardial infarction and peripheral vascular disease Previous stroke or TIA Atrial fibrillation Carotid artery disease Hypertension Diabetes Smoking Vasculitis Thrombophilia ```

Question 35

early complications of stroke

Answer 35

Haemorrhagic transformation of ischaemic stroke. Cerebral oedema. Seizures. Venous thromboembolism — pulmonary embolism hydration and nutritional difficulties pressure sores spasticity with pain and/or contractures Cardiac complications — cardiac complications (myocardial ischemia, congestive heart failure, atrial fibrillation, and arrhythmias) are common due to shared aetiology. Infection — people with stroke are at increased risk of infection including aspiration pneumonia, urinary tract infection, and cellulitis from infected pressure sores.

Question 36

long term complications

Answer 36

``` mobility sensory problems continence problems pain fatigue problems with swallowing, hydration adn nutrition sexual dysfunction skin problems visual problems cognitive problems difficulties with activities of daily living emotional and psychological problems communication problems financial problems ```

Question 37

mobility complications from stroke

Answer 37

hemiparesis or hemiplegia ataxia falls spasticity and contractures

Question 38

when do you suspect a TIA

Answer 38

sudden onset, focal neurological deficit which has completely resolved within 24 hours of onset and cannot be explained by another condition such as hypoglycaemia - Unilateral weakness or sensory loss. - Dysphasia. - Ataxia, vertigo, or incoordination. - Syncope. - Sudden transient loss of vision in one eye (amaurosis fugax). - Homonymous hemianopia. - Cranial nerve defects.

Question 39

when do u suspect stroke

Answer 39

longer than 24 hours onset - Confusion, altered level of consciousness and coma. - Headache – sudden, severe and unusual headache which may be associated with neck stiffness. Sentinel headache(s) may occur in the preceding weeks. Weakness − sudden loss of strength in the face or limbs. Sensory loss – paraesthesia or numbness. Speech problems such as dysarthria. Visual problems – visual loss or diplopia. Dizziness, vertigo or loss of balance — isolated dizziness is not usually a symptom of TIA. Nausea and/or vomiting. Specific cranial nerve deficits such as unilateral tongue weakness or Horner’s syndrome (miosis, ptosis, and facial anhidrosis). Difficulty with fine motor co-ordination and gait. Neck or facial pain (associated with arterial dissection

Question 40

when to suspect a posterior circulation strok

Answer 40

``` Symptoms of acute vestibular syndrome — acute persistent continuous vertigo dizziness with nystagmus nausea or vomiting head motion intolerance new gait unsteadiness. ```

Question 41

what do you ask in the histroy

Answer 41

clinical features mentioned such as headache vomiting decreased level of consciousness time of onset, activity at onset risk factors mentioned CVS disease smoking alcohol ``` PMH - miscarriage thromboembolic events past myocardial infarct (MI) • recent chest pain suggesting recent MI (or thoracic root aortic dissection) • atrial fibrillation • rheumatic fever as a child • valvular heart disease or valve replacement • symptoms of heart failure • palpitations • pacemaker PVD ``` FH of stroke or hyperlipidaemia or hypercoagulability current medications such as anticoagulants, HRT or illicit always take a collateral history ie witness ambulance personnel family members

Question 42

What has MRI showed in terms of TIA lasting longer than an hour

Answer 42

associated with a new infarction

Question 43

what conditions have a sudden onset

Answer 43

stroke epilepsy trauma

Question 44

what conditions have subacute onset that build up over hours or days

Answer 44

infectious inflammatory metabolic malignant

Question 45

main differentials for stroke/TIA

Answer 45

blackouts/syncope epilepsy migraine with aura metabolic, particularly hypoglycaemia

Question 46

Mx of stroke acutely MDT involved who

Answer 46

1. aspirin 300 mg AFTER CT SCAN daily for 2 weeks then clopidogrel 75 mg daily long-term. 2. Thrombolysis w altpeplase - tissue plasminogen activator - refere to stroke unit - monitor BP secondary prevention A statin should also be offered if the patient is not already on statin therapy. aspirin stop smoking ``` LONG TERM Nurses Speech and language (SALT) Dieticians Physiotherapy Occupational therapy Social services Optometry and ophthalmology Psychology Orthotics speech therapy liaison between district services and social workers ```

Question 47

Diagnostic of which area is affected

Answer 47

diffusion weighted MRI

Question 48

how do u initially manage a stroke pt

Answer 48

``` reassure pt monitor GCS CT/MRI to distinguish bloods - glucose, U&Es, FBC - polycythaemia, ESR ECG- AF,MI NBM ```