We have already discussed a bit of stroke and within carotid disease, TIA and stroke prevention
Carotid artery disease (CAD) refers to atherosclerotic plaque formation on either/both common carotid ± internal carotid arteries. It is a major risk factor for cerebrovascular events.
Pathophysiology
The pathophysiology is the same as with any other atherosclerotic plaque formation where we get response to injury due to turbulent flow, forming a fatty streak with a lipid core and a fibrous cap overlies this. This usually happens at locations of bifurcation and the bifurcation of the common carotid artery is a common location for this to occur.
🔢 Classification
We can classify it using radiology to assess the degree of stenosis:
Degree of stenosis | Diameter reduction |
Mild | <50% |
Moderate | 50-69% |
Severe | 70-99% |
Total occlusion | 100% |
⚠️ Risk factors
- Age
- Smoking
- Hypertension
- Hypercholestrolaemia
- Obesity
- Diabetes mellitus
- CVD
😷 Presentation
It is often asymptomatic and will present as a focal neurological deficit as either a stroke or TIA (we will discuss these separately next). Especially if unilateral, we get collateral supply from the contralateral ICA and vertebral arteries in the Circle of Willis.
On examination:
- Carotid bruits may be auscultated in the neck (using the diaphragm on held inspiration).
📝 Differential diagnosis
- Carotid dissection - patients are generally <50 years old and have connective tissue disorders. Occurs due to trauma or sudden movement of neck.
- Thrombotic occlusion of carotids - presents almost exactly same. It can only be differentiated on imaging.
- Fibromuscular dysplasia - hypertrophy of the vessel wall causing stenosis. Patients are younger (<50 years old). Mostly in females and mostly in the renal arteries.
- Vasculitis
- Todd’s paresis - unilateral motor paralysis following a seizure.
🔍 Investigations
Initial investigations
→ We’ll discuss stroke further but any stroke patient requires urgent non-contrast CT head to look for infarction.
→ If thrombectomy is considered, a CT head with contrast is needed.
Stroke patients also require:
- Bloods - FBC, U&Es, clotting profile, lipid profile, glucose levels.
- ECG - looking for AF.
Follow-up investigations
- Duplex ultrasound - is required to assess the extent of stenosis within the carotid arteries.
- CT angiography - is more accurate and can provide insight if surgery is considered.
🧰 Management
We’ll discuss acute management of stroke in the relevant section.
However, let’s discuss long term management for carotid disease:
- Aspirin 300mg OD for 2 weeks
- Followed by clopidogrel 75mg OD.
Statin therapy
- High-dose atarvostatin
- Carotid endarterectomy - is recommended for patients with symptomatic carotid stenosis or have had TIA. It no lives removal of the atheroma and any damaged intima layers of the vessel. ➡️
- Complications - stroke, nerve damage (hypoglossal, glossopharyngeal, vagus nerves), MI.
- Hypertension management
- Diabetes management
- Exercise and weight loss
- Smoking cessation
A TIA is a “mini-stroke”. It is a focal neurological deficit that lasts <24 hours before resolution. However, it usually lasts about an hour. There is ischaemia without infarction. TIAs precede a full stroke.
😷 Presentation
Similar to a stroke, but the features resolve and usually within an hour. By the time they see a doctor, they are generally resolved.
Some features we may see are:
- Unilateral motor weakness
- Unilateral sensory loss
- Aphasia/dysarthria
- Ataxia/vertigo
- Amaurosis fugax - due to blockage of the ophthalmic artery.
- Diplopia
A lot of it will depend on the region of ischaemia. We will delve deeper into some of the presentations of specific infarcted regions when we discuss stroke.
🔍 Investigations
NICE does not recommend a CT brain unless there is a suspicion of an alternative diagnosis where a CT could detect it. MRI may be used to determine ischaemic territory or haemorrhage. Should be done same day if possible. Carotid Duplex should be done urgently unless they are unable to have a carotid endarterectomy.
🧰 Management
Aspirin may be withheld if:
- They have a bleeding disorder or are on anitcoagulants already → need to exclude haemorrhage
- If they are taking 75mg OD aspirin already then a specialist needs to review the patient first.
- Contraindications to aspirin (salicylate hypersensitivity, asthma, haemophilia, severe cardiac failure).
Further management: 🥇 Clopidogrel is first line. 🥈 Aspirin + dipyridamole is used in patients who are intolerant to clopidogrel (6% of patients on clopidogrel develop allergy to it, which can present as angioedema, Stevens-Johnson syndrome, SIRS)
Specialist assessment is needed if:
- There has been a crescendo TIA or if the patient has a severe carotid stenosis.
- If the TIA happened within the past week then a specialist should see the patient within 24 hours
- If the TIA happened over a week ago then a specialist should be seen within 7 days.
Stroke is another CVA, except this lasts >24 hours without any resolution. Stroke is the 4th biggest killer in the UK. It is essentially a “brain attack”, where we have a sudden interruption in the blood supply to the brain. Unlike other tissues, the brain cannot rely on anaerobic metabolism, so if there is no oxygen we can get irreversible damage very rapidly.
The 3 main arteries supplying the brain are the cerebral arteries:
- Anterior cerebral artery - branch of ICA. Supplies the medial surface of the cerebral hemispheres (corpus callosum, frontal lobe, parietal love, cingulate gyrus).
- Middle cerebral artery - branch of ICA. Supplies the lateral surface of the cerebral hemispheres as well as the temporal pole. It traverses the Sylvia’s fissure and gives off some lenticulostriate branches which course as deep as the external surface of the thalamus and supply the basal ganglia.
- Posterior cerebral artery - branch of basilar artery. Mainly supplies the occipital lobe, inferomedial temporal lobe, midbrain, thalamus, choroid plexus (of lateral ventricles and third ventricle).
There are 2 main forms of stroke:
- Ischaemic stroke - a dry stroke. This is when there is a decrease in blood flow due to stenosis. This makes up about 87% of stroke caes. It may occur due to:
- Vascular pathologies - atherosclerosis, arterial dissection, vasculitis, thrombi/emboli.
- Cardiac pathologies - AF, myocardial ischaemia, patent foramen ovale causing emoboli to occlude cerebral arteries.
- Haematological pathologies - hypercoagulable or hyperaggregable states.
- Haemorrhagic stroke - a wet stroke. This is when we have a haemorrhage of an artery supplying the brain, leading to decreased perfusion to a region of the brain. It is rarer, resulting in 13% of stroke cases.
Let’s discuss some differences between the 2…
Ischaemic | Haemorrhagic | |
Essential problem | 'Blockage' in the blood vessel stops blood flow | Blood vessel 'bursts' leading to reduction in blood flow |
Proportion of strokes | 85% | 15% |
Subtypes | Thrombotic stroke
• thrombosis from large vessels e.g. carotid
Embolic stroke
• usually a blood clot but fat, air or clumps of bacteria may act as an embolus
• atrial fibrillation is an important cause of emboli forming in the heart | Intracerebral haemorrhage
• bleeding within the brain
Subarachnoid haemorrhage
• bleeding on the surface of the brain |
Risk factors | General risk factors for cardiovascular disease
• age
• hypertension
• smoking
• hyperlipidaemia
• diabetes mellitus
Risk factors for cardioembolism
• atrial fibrillation | Risk factors
• age
• hypertension
• arteriovenous malformation
• anticoagulation therapy |
😷 Presentation
Vascular causes of neurological symptoms are suspected when it is sudden onset.
Now we will take a look at specific strokes but the general features of strokes include:
- Motor weakness - sudden weakness of limbs and/or face
- Dysphasia
- Dysphagia
- Homonymous hemianopia
- Ataxia
- Hemisensory loss
Cerebral hemisphere infarcts:
- contralateral hemiplegia: initially flaccid then spastic
- contralateral sensory loss
- homonymous hemianopia
- dysphasia
Brainstem infarcts:
- may result in more severe symptoms including quadriplegia and lock-in-syndrome
Lacunar infarcts:
These are small infarcts around the basal ganglia, internal capsule, thalamus and pons (lenticulostriate arteries):
- this may result in pure motor, pure sensory, mixed motor and sensory signs or ataxia
A left MCA stroke is the most common stroke, so let’s take a look at its common presentation:
There are 6 common symptoms, they are not always present simultaneously but it is useful to be aware of all of them.
- Right hemiplegia - due to damage of the CST above the decussation (therefore contralateral).
- Right hemianaesthesia - due to the STT being affected after the decussation (therefore contralateral).
- Right sensory loss - due to DCML being affected after the decussation (therefore contralateral).
- Right homonymous hemianopia - as the left V1 cortex provides information on the right visual fields.
- Gaze preference to the left - as the left frontal eye fields (FEF) normally pulls the gaze to the right, therefore as it is lost the eyes look towards the stroke.
- Global aphasia - as it may affect both Broca’s and Wernicke’s areas (loss of both production and comprehension of speech).
🔢 Classification
We can use the Oxford Stroke Classification (Bamford Classification) to classify the type of stroke based on the initial symptoms:
According to this classification we need to assess 3 things:
- Unilateral hemiparesis ± hemisensory loss in the face, arm & leg
- Homonymous hemianopia
- Higher cognitive dysfunction such as dysphasia
Type of stroke | |
TACI - total anterior circulation infarct | → Involves MCA and ACA
→ All 3 of the criteria are present |
PACI - partial anterior circulation infarct | → Involves upper/lower divisions of MCA and smaller arteries of anterior circulation
→ 2 out of the 3 criteria are present |
LACI - lacunar infarct | → Involves perforating branches of the internal capsule, thalamus and basal ganglia (lenticulostriate branches)
1 of the following is present:
→ Unilateral weakness
→ Sensory loss
→ Ataxic hemiparesis |
POCI - posterior circulation infarct | →Involves the vertebrobasilar arteries
1 of the following is present:
→ Cerebellar/brainstem syndromes
→ Loss of consciousness
→ Homonymous hemianopia |
Anatomical presentation of stroke
Lacunar strokes present with an isolated hemiparesis, hemisensory loss, or hemiparesis + limb ataxia. It is strongly linked with hypertension.
To differentiate ischaemic from haemorrhagic strokes based on symptoms is not very easy. However, there are some things that can be used to differentiate the two…
Haemorrhagic strokes are more likely to have:
- Decreased consciousness
- Headache
- Nausea and vomiting
- Seizures
The FAST campaign raised awareness of stroke symptoms:
- F - Face. Has their face fallen on one side? Can they smile?
- A - Arms. Are they able to raise both arms and hold it there?
- S - Speech. Is their speech slurred?
- T - Time. It’s time to call 999 if any of these symptoms are present.
🔍 Investigations
Emergency neuroimaging is needed, mainly to assess suitability for thrombolytic therapies for ischaemic strokes:
If the score is >0 then a stroke is likely:
- Syncope - -1 point
- Seizure activity - -1point
- Acute onset of:
- Asymmetric facial weakness - +1 point
- Asymmetric arm weakness - +1 point
- Asymmetric leg weakness - +1 point
- Speech disturbance - +1 point
- Visual field defect - +1 point
- Serum glucose - as hypoglycaemia is a stroke mimic. Hyperglycaemic states are also associated with intracerebral bleeding and worse clinical outcomes when treated with IV thrombolysis therefore we need to exclude both before giving thrombolysis.
- Serum electrolytes
- Serum urea and creatinine
- Cardiac enzymes - to exclude concomitant MI.
- FBC
- ECG - to exclude AF and other arrhythmias.
- Clotting profile
🧰 Management
We need the urgent neuroimaging as we need to assess whether the stroke is of ischaemic or haemorrhagic aetiology as the treatment varies drastically.
Ischaemic strokes
<4.5 hours of onset and thrombolysis NOT contraindicated: A-E approach and stabilisation. Patient should also be referred to the stroke unit.
- Aspirin therapy - 300mg immediately and continued for 2 weeks.
- Clopidogrel can be used if intolerant to aspirin.
- Thrombolysis using alteplase - is used once we have excluded haemorrhagic aetiology. It is a tPA that activates plasmin to break down any thrombus. It depends on local protocols whether/when we use thrombolysis
- High-intensity statin - such as atorvostatin to be given after 48 hours.
- BP should not be lowered.
- Mechanical thrombectomy is a new treatment option. It should be done within 6 hours. If there is salvageable tissue (based on CT or MRI findings) after a posterior circulation infarct then it can be extended up to 24 hours.
>4.5 hours of onset or thrombolysis contraindicated:
We do the same things except we do not give a thrombolytic agent.
Haemorrhagic strokes
A-E approach and stabilisation. Patient should also be referred to the stroke unit.
Neurosurgical assessment is required, but most patients won’t be suitable for surgery.
- We need to avoid antithrombotics and anticoagulants.
- Trials have shown that lowering BP acutely has helped (<140/80mmHg)
- History of spontaneous intracerebral haemorrhage
- Ischaemic stroke within last 6 months
- CNS damage, neoplasm or AV malformation
- Major trauma, surgery, head injury within last 1 month
- GI bleeding within last 1 month
- Bleeding disorder
- Aortic dissection
- Non-compressible punctures within last 24 hours - such as liver biopsy or lumbar puncture.
This is a procedure that entails removal of a portion of the cranium to create space for a swelling or herniating brain to expand without being compressed.
The indications for decompressive craniectomy include 4 aspects which all need to be met:
- <60 years old
- Severe stroke symptoms
- Reduced consciousness
- CT defined infarct >50% of MCA territory
Long term/secondary prevention
- 🥇 Clopidogrel - 75mg OD
- 🥈 Aspirin 75mg OD + dipyridamole BD is the alternative.
- Atarvostatin to also be started, but not immediately.
- Carotid endarterectomy/stenting is also to be considered if carotid disease present.