Stroke Flashcards
What is the definition of Stroke?
Rapid permanent neurological deficit from cerebrovascular insult.
Also defined clinically, as focal or global impairment of CNS function developing rapidly and lasting >24h.
Can be subdivided by location (anterior circulation or posterior circulation) or by pathological process (infarction, haemorrhage).
Describe the epidemiology of Strokes
Common.
Annual incidence is two in 1000.
Third most common cause of death in industrialized countries. Most patients are in seventh decade. Young strokes (
Describe the blood supply to brain.
Brain’s blood supply can be divided into anterior and posterior circulations.
Ant. circ origionates from carotid arteries, supplying the frontal, parietal and part of temporal lobes.
Post circ arises from the vertebral arteries which join to form the basilar artery, supplies the occipital and medial temporal lobes, thalamus, brainstem and cerebellum.
In health ant. and post. circulations are joined by circle of willis.
Describe the pathogenesis in stroke.
Iscaemic strokes arise from occlusion of a blood vessel causing infarction of brain tissue.
Can arise through a variety of mechanisms, the most common being:
-Arterial atherosclerosis: thrombus forms on arterial atherosclerotic plaques in the internal carotid artery or intracranial vessels.
- Cardioembolism: Cardiac thrombus (arrising in atrial fibrilation or recent MI) travels to cerebral circulation
- Small-vessel occlusion (lacunar stroke): thrombus forms in small penetrating arteries that have been damaged by long-standing hypertension.
-Non-atheromatous disease:
Thrombus develops in arteries damaged by vasculitis or arterial dissection.
Strokes from haemorrhage can occur (10%).
What would a patient suffering a stroke describe in their history?
Sudden onset (deterioration within seconds)
Weakness, sensory, visual or cognitive impairment, impaired coordination, or consciousness.
Head or neck pain (in carotid or vertebral artery dissection).
Enquire time of onset (critical for emergency management if
Describe what would be found after a stroke in the anterior cerebral artery?
Lower limb weakness (motor cortex), confusion (frontal lobe)
Describe what would be found after a stroke in the middle cerebral artery?
Facial weakness
Hemiparesis (motor control)
Hemisensory loss (somatosensory cortex)
Apraxia
Hemineglect (parietal lobe)
Receptive or expressive dysphasia (language centres)
Quadrantanopia ( superior or inferior optic radiations).
Describe what would be found after a stroke in the small vessels. (lacunar)
- Internal capsule or pons
- Thalamus
- Basal ganglia
Internal capsule or pons:
Pure sensory or motor deficit (or combination of both)
Thalamus:
Loss of consciousness
Hemisensory deficit
Basal ganglia:
Hemichorea
Hemiballismus
Parkinsonism
Describe what would be found after a stroke in the posterior cerebral artery
Hemianopia
Describe what would be found after a stroke in the anterior inferior cerebellar artery
Vertigo
Ipsilateral ataxia
ipsilateral deafness (or tinnitus)
Ipsilateral facial weakness.
Describe what would be found after a stroke in the Posterior inferior cerebellar artery
(lateral medullary syndrome of Wallenberg)
Vertigo
Ipsilateral ataxia
Ipsilateral Horner’s syndrome
Ipsilateral hemifacial sensory loss
Dysarthria
Contralateral spinothalamic sensory loss.
Describe what would be found after a stroke in the basilar artery?
Combination of cranial nerve pathology and impaired consciousness.
EMERGENCY
Describe what would be found after multiple lacunar infarcts.
Vascular dementia,
urinary incontinence,
Gate apraxia (‘marche a petits pas,’ shuffling small-stepped gait, with upright posture and often normal or excessive arm-swing).
Describe what would be found on examination after a intracerebral haemorrhage
Headache meningism Focal neurological signs Nausea and vomiting Signs of raised ICP Seizures
Describe what would be found on examination after a subarachnoid haemorrhage
Meningism:
Neck stiffness,
Kernigs sign (resistance or pain on knee extension when hip is flexed) because of irritation of the meninges by blood.
Pyrexia may also occur.
Glasgow Coma Scale: Assess and regularly monitor for deterioration.
Signs of increased intracranial pressure: Papilloedema, IV or III cranial nerve palsy. Hyper-tension and bradycardia.
Fundoscopy: Rarely subhyaloid haemorrhage (between retina and vitreous membrane).
Focal neurological signs: Usually develop on second day and are caused by ischaemia from vasospasm and reduced brain perfusion. Aneurysms may cause pressure on cranial nerves causing ophthalmoplegia (classically III nerve or VI nerve palsy)
Give a brief example of clinical signs expected after an anterior circulation stroke
More common than post circ.
Clin features include hemiplegia, hemisensory disturbance, dysphasia and sensory neglect.
Give a brief example of clinical signs expected after a posterior circulation stroke
Affects occipital lobes, cerebellum or brainstem.
Damage to occipital lobes results in homonymous hemianopia
Cerebellar strokes present with vertigo, vomiting and ataxia
Brainstem strokes present with hemiparesis, coma, cranial nerve palsies, ataxia and vertigo.
Basillar artery occlusion may rarely result in “locked-in syndrome.”
- complete loss of speach and quadriplegia
- preserved consciousness and normal eye movements.
What investigations would you perform for a patient with a suspected stroke?
Investgations have two main aims, confirmation of diagnosis and to distinguish ischaemia from haemorrhage, and secondly to identify the underlying cause of stroke.
Blood: FBC, U&E, glucose, clotting profile, lipids (consider thrombophilia screen especially in young patients).
ECG:
To identify any arrhythmias which pre-dispose to embolism.
Echocardiogram:
Identifies cardiac thrombus, valvular endocarditis or other sources ofembolism.
Consider bubble contrast study for right-to-left shunt (e.g. VSD)
Carotid Doppler ultrasound:
Important to exclude carotid artery disease.
CT-head: For rapid detection of haemorrhages. Often normal especially in lacunar infarcts or very early in the stroke (
How would you manage a patient with a stroke acutely.
Acute management
Patients should be managed in specialised stroke unit
all patients with ischaemic stroke should reveive aspirin within the first 48 hours.
Ischaemic stroke presenting within 3hrs of onset should be considered for thrombolysis.
-this may reduce disability after stroke but carries a risk of life threatening haemorrhage.
How would you manage a patient with a stroke (secondary prevention)?
Vascular risk factors should be identified and managed appropriately (eg cigarettes, hypertension, diab mellitus)
Long term antiplatelet therapy (usually aspirin and often dipyridamole) is generally indicated after ischaemic stroke.
-Clopidogrel may be useful if aspirin is not well tolerated.
Warfarin is preferred to antiplatelet agents in individuals with atrial fibrillation unless specific contraindications present.
ACE inhibitors and statins have been shown to be beneficial, usually prescribed.
Individuals with significant carotid artery stenosis (>70%) should be considered for carotid endarterectomy.
What is a Transient Ischaemic Attack?
The term is used to describe episodes in which neurological deficits fully resolve within 24hrs.
What is amaurosis fugax?
A sudden monocular visual loss arising from temporary occlusion of the opthalmic artery.
Highly suggestive of significant ipsilateral carotid stenosis.
What affect does having a TIA have on the likelyhood of suffering a stroke.
TIA is a strong predictor of subsequent stroke.
-Approx 30% of indiv with a TIA develop a stroke within the next 5 years.
Risk of stroke is greatest soon after the TA
- 5-10% within 1 week
- 10-20% within 3 months.
Urgent investigation and apppropriate management are vital.
What would predispose somebody to having a venous sinus thrombosis?
Hypercoagulable states oral contraceptive pill dehydration mastoid infection direct pressure on a venous sinus (eg from tumor)
No cause is found in up to 25%
How would you diagnose and manage a venous sinus thrombosis?
CT or MRI venography usually required to confirm diagnosis.
-Standard CT may be normal in this condidtion.
Management is with anticoagulation and treatment of underlying cause.
What clinical features can appear in some patients with venous sinus thrombosis?
Some patients experience neurological deficits and paipilloedema.
