Clinical Lecture: Stroke and TIA Flashcards
What is a stroke?
An abrupt interruption to the blood supply of the brain. This can result due to a rupture or a blockage (85%). Within a few minutes brain cells die.
What are the main mechanisms of stroke?
Embolism: A clot can leave the heart and lodge in the brain and cause a stroke.
A clot can also be formed in the small vessels in small vessel disease. The most common mechanism for this is hypertension and diabetes (especially poorly controlled).
Hypoperfusion - difficulty supply of the sink
If the blood pressure drops the blood cannot reach the distant areas of the brain e.g. the grey area.
This can happen in cases of low systemic pressure or an MI.
Clot formation
E.g. haematological diseases such as polycythaemia, any systemic hypercoagulable state or arteritis. This is not the most common.
Give mechanisms of a stroke due to an embolism.
The most common mechanisms of this are:
- Rhythm (e.g. atrial fibrillation)
- Valvopathies (e.g. AVE, ischemic endocarditis)
- Chambers pathology e.g. clots in the left ventricle, MI
- Aortic arch (atheroma)
In significant atherosclerosis (more than 50% or narrowing), mural thrombus or dissection, we can see large vessel embolism.
What is the most common aetiology of a non-traumatic intra-cranial haemorrhage?
Hypertensive damage to blood vessel walls (eg, hypertension, eclampsia, drug abuse).
What are common stroke symptoms?
- Slurred Speech
- Facial Droop
- Acute unilateral loss of sensation or strength
- Aphasia
- Ataxia and/or vertigo
- Double vision
- Sudden decrease in level of consciousness
- Acute monocular or binocular visual loss (complete or incomplete)
What is the penumbra?
Ischemic penumbra refers to a rim of tissue lying just outside the core ischemic region (area most severely damaged by stroke or ischemic event). Within the core ischemic region, blood and oxygen flow is severely diminished, resulting in neuronal death. If we do not do something as soon as we can it is at risk of dying.
What percentage of stroke is due to ischaemia?
Ischemic stroke occurs when a vessel supplying blood to the brain is obstructed. It accounts for about 85-87% of all strokes.
What are the options for recanalization in a stroke?
- Clot buster if given within 48 hours (Alteplase)- very strong blood thinning medication and so associated with a significant bleeding risk. In the first 7 days they have a significant risk of mortality. After which in the survivors, it makes a big difference in the final functional outcome.
- We can use mechanical thrombectomy (MT) access in the arteries from the groin. We use a catheter to pull the clot out physically
What is a TIA?
A Transient Ischaemic Attack (TIA) - a neurological deficit that least for less than 24 hours due to ischemia to the brain or the eye (or the retinal circulation). It is an arbitrary unit. Most last for under 60 minutes. It does not mean there is no brain damage. More detailed scans can show evidence of cerebral injury.
Give example of causes of TIA.
The same causes of stroke e.g. cardiac embolism, carotid artery disease (large artery disease) or cerebral small vessel disease.
Give examples of syndromes that mimic TIAs.
- Seizures
- Syncope - initial symptoms, it is unusual to lose consciousness in a TIA
- Hypoglycaemia
- Migraine
- Acute confusion states
What is the ABCD2 score?
The ABCD2 score is a seven-point score for identifying patients who have suffered a transient ischemic attack (TIA) at the highest risk of stroke in the following 2-day period. It looks at Age, BP, Clinical features (unilateral weakness and speech disturbance), duration fo symptoms and whether the patient is diabetic.
How can we use secondary vascular prevention?
- Diet
- Exercise
- Aspirin
- Anticoagulants
- Stopping smoking -most important to mention
- Diabetic control
- Surgery e.g. carotid endarterectomy to remove the plaque by opening the artery to reduce the risk of stroke. The sooner the surgery is done the better
