Stroke Flashcards
How common is it?
Third most common cause of death in the UK. Per annum, 110,000 strokes and 20,000 TIAs. More than 900,000 in England are living with the effects
Who does it affect?
Most occur in people over 65
What are the two types of ischaemic stroke?
A blood vessel is blocked, by something like the fatty material or a clot. The affected areas of the brain die from lack of oxygen.
Thrombotic ischaemic stroke: A blood clot spontaneously forms in an artery in the brain. This is a common complication of atherosclerosis.
Embolic ischaemic stroke: Part of the fatty material from an atherosclerotic plaque or a clot in a larger artery or the heart breaks off and travels downstream until it’s trapped by a narrower artery in the brain (Think AF)
What are the two types of haemmorhagic stroke?
Intracerebral haemorrhagic stroke: There is bleeding from a blood vessel within the brain. High blood pressure is the biggest cause of this.
Subarachnoid haemorrhage: Bleeding between the brain and the arachnoid matter.
Some experts do not classify a subarachnoid haemorrhage as a stroke as they present differently to ischaemic strokes/intracerebral haemorrhages, and require different treatment.
What risk factors are there?
The major risk factors for thromboembolic stroke are those for atheroma i.e. Hypertension, diabetes, smoking and hyperlipidaemia. Also obesity, COCP, excessive alcohol consumption and polycythaemia. AF is also a big risk factor (rate 1-5% per year depending on age). Rarer causes of stroke are migraine, vasculitis, cocaine (by causing vasoconstriction), antiphospholipid syndrome and the thrombophilia’s.
How does it present?
Carotid territory symptoms: Amaurosis fugax (transient loss of vision, aphasia, hemiparesis, hemisensory loss, hemianopic loss.
Vertebrobasilar territory symptoms: Diplopia, vertigo, vomiting, choking and dysarthria, ataxia, hemisensory loss, meianopic or bilateral visual loss, tetraparesis, loss of consciousness (rare)
Investigations
Blood: Glucose, FBC (to identify polycythaemia), ESR (raised in the few cases of vasculitis), creatinine, electrolytes, cholesterol and INR (if taking warfarin).
Brain imaging: By diffusion weighted MRI together with specialist review should be performed within 24 hours in patients with an ABCD score >4 or if they have crescendo TIAs (2 or more in a week). CT is used when MRI is contraindicated or unavailable. Brain imaging should be >1week in lower risk patients.
Carotid artery imaging: Carotid Doppler and duplex US scanning are performed to look for carotid atheroma and stenosis. MR angiography or CT angiography are performed if US suggests carotid stenosis to determine the degree of stenosis.
Treatment
Ischaemic: Alteplase within 4.5 hrs of onset. Aspirin 300mg and then continued long term (75mg) with 200mg TDS modified dipyridamole. Clopidogrel can be given instead of aspirin. Lifestyle changes for secondary prevention. Carotid endarterectomy is recommended in patients with carotid artery stenosis (>70%). Successful surgery reduces the risk of further stroke by 75%. Has a 3% chance of mortality and similar chance of stroke.
Haemorrhagic: Anticoagulants should be stopped and their effects reversed by prothrombin complex concentrates. The decision to resume anticoagulants is made on a case by case basis. Patients with a large intracerebral haematoma causing deepening coma or brainstem compression or patients with a cerebellar bleed causing hydrocephalus as a result of obstruction of the drainage pathways for CSF should be immediately referred for neurosurgical evaluation.
Conditions that would present similarly
Hypoglycaemia.
Conditions which cause dizziness, faintness or disturbed balance.
Migraine.
Neurological abnormalities (e.g. MS, focal neuropathy, previous stroke).
Mass lesions.
Postictal states and seizures.
Hyperglycaemia.
Hyponatraemia and hepatic encephalopathy.
Facitious stroke (functional hemiparesis).
Anxiety.
Physical trauma.
