Cerebrovascular Disease Flashcards
What is a stroke?
Sudden onset of a focal neurological deficit, lasting more than 24 hours (or leading to death) due to either infarction (85%) or haemorrhage (15%).
Stroke should be suspected in all patients with acute neurological deficit.
Rosier score
ROSIER SCALE TO DIFFERENTIATE STROKE AND “STROKE MIMICS”
Has there been loss of consciousness or syncope? Y (-1) N (0)
Has there been seizure activity? Y (-1) N (0)
Is there a new onset (or waking from sleep?):
i Asymmetric facial weakness Y (+1) N (0)
ii Asymmetric arm weakness Y (+1) N (0)
iii Asymmetric leg weakness Y (+1) N (0)
iv Speech disturbance Y (+1) N (0)
v Visual field defect Y (+1) N (0)
Score Likelihood of Stroke
1-6 = Stroke is likely
= 0 Low probability of stroke but not excluded
Bamford Classification of Ischaemic Stroke
- Total Anterior Circulation Stroke (TACS)
- Partial Anterior Circulation Stroke (PACS)
- Lacunar Stroke (LACS)
- Posterior Circulation Stroke (POCS)
Total Anterior Circulation Stroke (TACS)
Affects MCA - middle cerebral artery
Hemiparesis +/- hemisensory loss AND Homonymous hemianopia AND Cortical dysfunction (dysphasia /perceptual or visuospacial problem)
Partial Anterior Circulation Stroke (PACS)
2 of the 3 below: Hemiparesis +/- hemisensory loss Homonymous hemianopia Cortical dysfunction (dysphasia / perceptual problem) OR Cortical dysfunction alone
Lacunar Stroke (LACS)
- most common ischemic stroke
- lipohyalinosis + HTN in small penetrating arteries
- affects internal capsule and basal ganglia
Hemiparesis OR Hemisensory loss OR Hemisensorymotor loss OR Ataxic hemiparesis
- No cortical dysfunction or hemianopia *
Posterior Circulation Stroke (POCS)
- Brainstem nuclei or cerebellar signs /symptoms
loss of consciousness or isolated homonymous hemianopia, colour agnosia, dysarthria, dysphagia, ataxia, vertigo, diplopia or quadruparesis/ bilateral limb problems.
- better seen on MRI due to presence of bone obstructing view
Examples of POCS
- Vertebrobasilar stroke = Cranial nerve deficits 3rd to 12th. Can have bilateral blindness or hemianopia, confusion, diplopia, slurred speech or vertigo
- subclavian steal syndrome = occluded subclavian > retrograde circulation in vertebral or internal thoracic at expense of vertebrobasilar flow > dizziness, vertigo, arm pain
- basilar artery occlusion (locked in syndrome) = loss of speech, quadriplegia, preserved cognitive function
Stroke - investigations
- CT head (distinguish ischaemic and haemorrhagic). Also necessary before starting aspirin or thrombolysis
- serum glucose (exclude hypoglycaemia)
- serum electrolytes (exclude electrolyte disturbance)
- serum urea and creatinine (exclude renal failure)
- cardiac enzymes (exclude MI)
- ECG (exclude arrhythmias)
- FBC (exclude anaemia or thrombocytopenia prior to anticoagulant therapy and as cause of haemorrhage)
- clotting screen
Ischaemic stroke - acute management
- Aspirin 300mg ASAP (PO/PR/NG) – if no bleed on scan
- Stroke Unit
ABCDE approach - give oxygen if < 95%
Early SALT (speech and language) input
Early feeding (bedside swallow test before eating or drinking - done within 4 h of arrival) - VTE prophylaxis + early mobilisation: heparin or dalteparin or enoxaparin
Ischaemic core vs Ischaemic penumbra
ISCHAEMIC CORE (irreversible damage) : Area of brain tissue local to the blood vessel occlusion, whose blood supply is entirely supplied by this vessel, dies.
ISCHAEMIC PENUMBRA (SALVAGEABLE TISSUE): Surrounding the ischaemic core is an area with some collateral blood supply (blood flow is reduced). Without intervention much of this will also die.
Clinical significance of ischaemic penumbra
- Most patients no longer have a penumbra beyond 4.5 hours
- Ischaemic core becomes more friable
- Risk of bleeding is higher and usually outweighs benefits of thrombolysis - hence why thrombolysis ONLY given within 4.5 h of symptom onset
As the penumbra disappears, stroke therapy such as thrombolysis becomes ineffective
Ischaemic stroke - hyperacute treatment
1st line - thrombolysis (if within 4.5 h)
2nd line - Thrombectomy/Mechanical Clot Retrieval
Thrombolysis not appropriate in some patients eg too young or too old, recent surgery, recent trauma or recent stroke, comatose or severely ill etc.
Thrombolysis
IV Alteplase 0.9mg/kg
- Bolus – 10% of total dose
- Infusion over 1 hour (remainder of drug)
Urgent CT brain to exclude bleed prior to treatment
Complications include bleeding & angio-oedema
Repeat CT Brain at 24 hours
Thrombectomy/Mechanical Clot Retrieval
- Currently offered up to 6 hours post symptom onset
- Can be as 1st line but usually as 2nd line treatment after failed thrombolysis
(or both can be offered together if criteria are met)
Done under local or general anaesthesia; initially get cerebral angiography to locate occlusion –> catheter usually through femoral, contrast dye inserted and x rays taken; Clot retrieval device attached to a guidewire through the delivery catheter to the occlusion site
