STROKE AND HAEMORRHAGE Flashcards
Define stroke.
A syndrome of rapid onset of cerebral deficit (usually focal) lasting more than 24 hours or leading to death, with no apparent cause other than a vascular one.
Define transient ischaemic attack.
A brief episode of neurological dysfunction due to temporary focal cerebral or retinal ischaemia without infarction. TIAs may herald a stroke.
What are the main two underlying causes of a stroke?
Infarction or haemorrage
What are the different causes of an ischaemic stroke (rather than a haemorragic stroke)?
Thrombotic event Large artery stenosis Small vessel disease Cardio-embolic Hypoperfusion
What are the two types of haemorrhagic stroke?
Intracerebral haemorrhage
Subarachnoid haemorrhage
How does large artery stenosis cause an ischaemic stroke?
Usually causes a stroke by acting as an embolic source rather than by occlusion of the vessel (which may not in itself cause stroke if it occurs gradually and collateral circulation is adequate)
What are the main sites of stenosis in the large arteries leading to the head?
Stenosis occurs most often at arterial branch points.
4 most common sites in order: Common carotid Internal carotid Vertebral artery Subclavian artery
Is the caucasian population more or less affected by strokes than the non-caucasian population?
Non-caucasian population tend to have more intracranial narrowing and white populations tend to have more extracranial disease (coronary artery and peripheral artery disease)
What is lipohyalinosis?
Small-vessel disease in the brain characterised by vessel wall thickening and a resultant reduction in luminal diameter. Recent evidence suggests that endothelial dysfunction as a result of inflammation is the most likely cause for it. This may occur subsequent to blood–brain barrier failure, and lead to extravasation of serum components into the brain that are potentially toxic. Lacunar infarction could thus occur in this way, and the narrowing – the hallmark feature of lipohyalinosis – may merely be a feature of the swelling occurring around it that squeezes on the structure.
What is a cardio-embolic stroke?
Stroke caused by emboli originating in the chambers of the heart.
What is the most common cause of cardio-embolic stroke?
Atrial fibrillation causing thrombosis in a dilated left atrium.
Other than AF, what are the other causes of cardio-embolic stroke?
Cardiac valve disease (including congenital valve disorders) Infective vegetations Rheumatic and degenerative changes Mural thrombosis in damaged ventricle Patent foramen ovale may allow fragments of venothrombus through to left side when performing Valsava causes shunting. Pulmonary arteriovenous fistulas Fat emboli after long bone fracture Atrial myxoma (tumour) Iatrogenic causes (e.g cardiac bypass)
What area of the brain is particularly vulnerable to stroke from hypoperfusion as a result of cardiac arrest?
Parieto-occipital area between middle and posterior cerebral artery. Hypoperfusion usually leads to borderzone infarction in the watershed areas between vascular territories, particularly if there is severe stenosis of proximal carotid vessels.
What is most common cause of transient ischaemic attacks?
Micro-emboli from cardiac thrombus and atheromatous plaques/thrombus within the aortic arch, carotid and vertebral systems.
What are the main risk factors for stroke?
Hypertension Smoking Sedentary lifestyle Alcohol High cholesterol Atrial fibrillation Obesity Diabetes Severe carotid stenosis Obstructive sleep apnoea (leading to cardiac damage and cardiac-emboli)
What are the less common risk factors and rarer causes of stroke?
Thrombocythaemia, polycythaemia and hyperviscosity states. Antiphospholipid syndrome. Low-dose oestrogen containing oral contraceptices in the presence of other risk factors. Migraine Vasculitis Amyloidosis Neurosyphilis Sympathomimetic drugs such as cocaine
What is CADASIL (cerebral dominant arteriopathy with subcortical infarcts and leucoencephalopathy)?
The most common form of hereditary stroke disorder, and is thought to be caused by mutations of the Notch 3 gene on chromosome 19. The disease belongs to a family of disorders called the Leukodystrophies. The most common clinical manifestations are migraine headaches and transient ischemic attacks or strokes, which usually occur between 40 and 50 years of age, although MRI is able to detect signs of the disease years prior to clinical manifestation of disease.
What are the features of a transient ischaemic attack due to an occlusion of the carotid system?
Amaurosis fugax Aphasia Hemiparesis Hemisensory loss Hemianopic visual loss
What is amaurosis fugax?
Sudden transient loss of vision in one eye. When due to the passage of emboli through the retinal arteries, arterial obstruction is sometimes visible through an opthalmoscope. Associated feature of a TIA.
What is aphasia?
Problems with language
What is hemianopic visual loss?
Loss of one visual field most often in both eyes.
What are the features of a transient ischaemic attack due to an occlusion of the vertebral system?
Diplopia Vertigo Vomiting Choking and dysarthria Ataxia Hemisensory loss Hemianopic visual loss Bilateral visual loss Tetraparesis Loss of consciousness (rare) Transient global amnesia
What is diplopia?
Double vision
What is dysarthria?
Difficulty speaking due to loss of muscle control
What is ataxia?
Loss of coordination and muscle movement
What is hemiparesis?
Paresis in one arm and one leg on one side of the body
What clinical findings might be detected in someone who presents with the symptoms of a TIA?
Carotid arterial bruits Atrial fibrillation Valvular heart disease/endocarditis Recent MI Atheroma Hypertension Postural hypotension Bradycardia or low cardiac output Diabetes Rarer: Arteritis, polycythaemia, neurosyphilis, HIV, antiphospholipid syndrome
What is the ABCD2 score and when is it used?
A score that can help stratify risk of stroke in TIA patients in the next few days:
Age >60 = 1 point
BP > 140 mmHg systolic or >90 diastolic = 1 point
Clinical features:
unilateral weakness = 2 points
isolated speech disturbances = 1 point
other = 0 points
Duration of symptoms
>60 mins = 2 points
10-59 = 1 point
Diabetes = 1 point
1-3 low risk (1.2% in the next week)
4-5 moderate risk (5.9% in the next week)
6-7 high risk (11.7% in the next week)
What investigations should be performed with someone having a TIA?
Doppler of internal carotid arteries
Cardiac echo
ECG
CT/MRI brain including angiography
What are the neurological deficits of a stroke associated with an occlusion of the left middle cerebral artery?
Right sided weakness involving face and arm (more than leg) with dysphasia (problems speaking)
What are the neurological deficits of a stroke associated with an occlusion of the right middle cerebral artery?
Left sided weakness involving face and arm (more than leg) with visual and/or sensory neglect and denial of disability
What are the neurological deficits of a stroke associated with an occlusion one of the posterior cerebral arteries?
Homonymous hemianopia (loss of the same visual field in both eyes) with varied deficits due to parietal and/or temporal lobe damage.
What are the neurological deficits of a stroke associated with an occlusion of one of the lenticustriate arteries which supply the internal capsule?
Motor, sensory or sensorimotor loss
Weakness in face, arms and legs
Possible profound dysarthria (loss of control of muscle associated with speaking) but not dysphasia (problems with language)
What are the neurological deficits of a stroke associated with carotid artery dissection?
Ipsilateral Horner’s syndrome (from compression of sympathetic plexus around the carotid artery)
Can also affect cranial nerves X and XII
What is the vascular supply most likely to be affect when a patient presents with the following neurological deficits?
Left sided weakness involving face and arm (more than leg) with visual and/or sensory neglect and denial of disability
Right middle cerebral artery
What is the vascular supply most likely to be affect when a patient presents with the following neurological deficits?
Ipsilateral Horner’s syndrome (from compression of sympathetic plexus around the carotid artery)
Can also affect cranial nerves X and XII
Carotid artery dissection
What is the vascular supply most likely to be affect when a patient presents with the following neurological deficits? Homonymous hemianopia (loss of the same visual field in both eyes) with varied deficits due to parietal and/or temporal lobe damage.
Posterior cerebral artery
What is the vascular supply most likely to be affect when a patient presents with the following neurological deficits?
Right sided weakness involving face and arm (more than leg) with dysphasia (problems speaking)
Left middle cerebral artery
What is the vascular supply most likely to be affect when a patient presents with the following neurological deficits?
Motor, sensory or sensorimotor loss
Weakness in face, arms and legs
Possible profound dysarthria (loss of control of muscle associated with speaking) but not dysphasia (problems with language)
Lenticustriate arteries which supply the internal capsule
What is lateral medullary syndrome?
Brainstem infarction which is the result of thrombosis of the posterior inferior cerebellar artery (PICA). Clinical symptoms include dysphagia, slurred speech, ataxia, facial pain, vertigo, nystagmus, Horner’s syndrome, diplopia, and possibly palatal myoclonus.
In the case of a cerebral infarction, what is the time window for thrombolysis?
Up to 4.5 hours. The sooner the better.
What is the thrombolytic agent most often used in the acute treatment of cerebral infarction?
Alteplase 0.9 mg/kg (max 90 mg)
What investigations should be done with a patient who presents with the signs and symptoms of stroke?
Head CT/MRI - to distinguish between ischaemic and haemorrhagic stroke.
What is the long term medical management of a stroke patient who has been treated with thrombolysis?
Antihypertensive therapy
Dual antiplatelet therapy - aspirin 75 mg, clopidogrel 75 mg
Anticoagulation therapy - heparin and warfarin should be given to those in AF or with other paroxysmal arrythmias.
When is internal carotid endarterectomy indicated in patients who have suffered a stroke or TIA?
When stenosis is more than 70%, but less than 100%
What are the signs and symptoms associated with cerebellar haemorrhage?
Headache
Stupor/coma
Gaze deviates towards the haemorrage
Sometimes causes acute hydrocephalus - surgical emergency.
What are the causes of a subarachnoid haemorrhage (SAH)?
Saccular (berry) aneurysm Arteriovenous malformation (AVM) - often involving fistula between arterial and venous system causing high flow through the AVM.
What are the risk factors for a berry aneurysm?
C SHAME Cocaine Smoking Hypertension Adult polycystic kidney disease Marfan's syndrome Ehlers-Danlos syndrome
Where are the most common sites for a berry aneurysm to form?
APM
Anterior communicating artery
Posterior communicating artery
Trifurcation or bifurcation of the middle cerebral artery
What are the clinical features of a subarachnoid haemorrhage?
Sudden very severe headache (thunderclap)
Usually followed by vomiting and then coma
Neck stiffness
Kernig’s sign - pain when extending leg when hip is flexed in lying position (usually done for meningitis)
Papilloedema
If head CT is unable to identify or rule out subarachnoid haemorrhage, what further investigation should be performed?
Lumbar puncture (CSF becomes yellow within 12 hours)
What is the management of subarachnoid haemorrhage?
Bed rest and supportive measures
Nimodipine (calcium channel blocker) reduces mortality
Treat aneurysm
What is the treatment of a berry aneurysm?
Endovascular treatment by placing platinum coils via a catheter in the aneurysm sac to promote thrombosis and ablation.
What is diameter of a berry aneurysm, below which the risks of treatment outweighs the risk of haemorrhage?
8 mm
What is conjugate eye deviation and stroke associated with which artery would cause this symptom?
When both eyes look towards the lesion and away from the side of weakness due to damage to the frontal lobe eye field. Most commonly seen in middle cerebral artery stroke. Carries a poor prognosis.
What is expressive dysphasia, damage to which area of the brain is it associated with and hence stroke associated with which artery causes this symptom?
Non-fluent, hesitant speech with intact comprehension. The patient what he or she wants to say but has difficulty finding the correct words, often producing the wrong word. The ability to repeat words is better than spontaneous speech. Handwriting is also often poor. This is as a result of damage to Broca’s area in the dominant frontal lobe (one side only). The area is supplied by the middle cerebral artery.
What is Gerstmann’s syndrome?
Consists of the inability to differentiate the right and left sides of the body, inability to distinguish fingers of the hand (finger agnosia) and impairment of calculation (dyscalculia) and writing (dysgraphia). Lesions in the dominant parietal lobe will lead to the develop of one or more of these symptoms. Arises as a result of middle cerebral artery stroke.
