2- Stroke: Summary (1) Flashcards
define stroke
Stroke
“a neurological deficit attributed to an acute focal injury of the central nervous system (CNS) by a vascular cause, including cerebral infarction, intracerebral hemorrage (ICH), and subarachnoid hemorrhage (SAH)”
physiology of stroke
- stroke symptoms are caused by hypoperfusion in the endothelial lumen
- this reduces oxygen and glucose which in turn reduces ATP synthesis in neurovascular unit
- this leads to impairment of energy dependent cell processes → causes action potential arrest
- this reduces neuronal transmission
TIA
“a transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischemia, without acute infarction.”
- symptoms usually resolve <24hr
types of stroke
- Ischaemic (85%)
- thromboembolic
- Haemorrhagic (10%)
- Intracerebral
- Subarachnoid
- Other (5%)
- Dissection
- Venous sinus thrombosis
- Hypoxic brain injury
causes of stroke in the young…
- Vasculitis
- Thrombophilia
- Subarachnoid haemorrhage
- Venous sinus thrombosis
- Carotid artery dissection e.g. via near strangling or fibromuscular dysplasia
causes of stroke in the old…
- Thrombosis in situ
- Athero-thromboembolism e.g. from carotid arteries
- Cardiac emboli (e.g. atrial fibrillation, infective endocarditis or MI)
- CNS bleed associated with hypertension, head injury, aneurysm rupture)
- Sudden blood pressure drop by more than 40 mmHg
- Vasculitis e.g. giant cell arteritis
- Venous sinus thrombosis
key causes o
RF for stroke
- HTN
- smoking
- DM
- heart disease
- valvular
- ischaemic
- atrial fib
- peripheral arterial disease
- Post-TIA (high risk pf early stroke)
- carotid artery occlusion
- polycythemia vera
- COCP
- hyperlipidaemia
- excess alcohol
- clotting disorders
RF for stroke
- HTN
- smoking
- DM
- heart disease
- valvular
- ischaemic
- atrial fib
- peripheral arterial disease
- Post-TIA (high risk pf early stroke)
- carotid artery occlusion
- polycythemia vera
- COCP
- hyperlipidaemia
- excess alcohol
- clotting disorders
stroke presentation
will be dependent on which cerebral artery is affected → ref to Bamford/oxford classification
general signs and symptoms:
- Sudden numbness or weakness in the face, arm, or leg, especially on one side of the body.
- Sudden confusion, trouble speaking, or difficulty understanding speech.
- Sudden trouble seeing in one or both eyes.
- Sudden trouble walking, dizziness, loss of balance, or lack of coordination
DD for stroke
- Always exclude hypoglycaemia as a cause of sudden-onset neurological symptoms.[6]
- TIA in the first 24 hours of the stroke.
- Brain tumour.
- Subdural haematoma.
- Todd’s palsy.
- Consider acute poisoning if the patient is comatose.
investigations for stroke
-
Bedside
- BP
- ECG
- BMs
-
Blood tests
- FBC
- test for sickle cell
- thrombophilia screen
- ESR- giant cell arteritis
- syphillis
- blood culture (endocarditis)
-
Brain imaging
- non-enhanced CT scan
- CT contrast angiography
-
Further investigations
- carotid duplex US
- Echocardiogram
- CXR
- 24hr tape
brain imaging for strpke
Brain imaging with non-enhanced CT should be undertaken immediately if the patient:
- Has indications for thrombolysis or early anticoagulant treatment.
- Is currently taking anticoagulant treatment.
- Has a known bleeding tendency.
- Has a depressed level of consciousness (Glasgow Coma Score below 13).
- Has unexplained progressive or fluctuating symptoms.
- Has papilloedema, neck stiffness or fever.
- Has severe headache at onset of stroke symptoms.
when should imaging with CT contrast angiography be performed
if thrombectomy might be indicated.[
when should imaging occur
s soon as possible and within 24 hours of symptom onset in everyone with suspected acute stroke without indications for immediate brain imaging.
assessments used after initial stroke presentation
NIHHS
acute management of ischaemic stroke
REPERFUSION
Opening up the blocked vessel in ischaemic stroke to reperfuse the ischaemic brain
-
Thrombolysis = clot busting
- Alteplase
- Thrombectomy = mechanically removed clot
thrombolysis MOA
when is thrombolysis appropriate
- Clinical diagnosis of acute ischaemic stroke causing one or more of an NIH score ≥ 4, aphasia, binocular visual field deficit, a swallowing deficit.
- Imaging appearances consistent with ischaemic stroke
- Symptom-onset within 4.5 hours prior to initiation of thrombolysis treatment
- give as early as possible
- The old benefit as much as the young
- No contraindications (think bleeding risk)
- E.g. bleeding tendencies which could make them more likely to haemorrhage
why use thrombolysis
- Opens up blocked vessels
- Improves independence
thrombectomy
- Other way of opening up blood vessels
- Mechanical
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