neuro Flashcards
What are the 2 main types of stroke?
& definition
Ischaemic- Ischaemia or infarction of the brain tissue secondary to a disrupted blood supply
Haemorrhagic- Intracranial haemorrhage, with bleeding in or around the brain
What is the WHO definition of stroke?
a clinical syndrome consisting of rapidly developing clinical signs of focal (or global) disturbance of cerebral function, lasting more than 24 hours or leading to death, with no apparent cause other than that of vascular origin
What is a transient ischaemic attack?
TIA involves temporary neurological dysfunction (lasting less than 24 hours) caused by ischaemia but without infarction
Risk factors for a TIA
atrial fibrillation
valvular disease
carotid stenosis
intracranial stenosis
congestive heart failure
hypertension
hyperlipidaemia
diabetes mellitus
cigarette smoking
alcohol-use disorder
advanced age
What are crescendo TIAs?
two or more TIAs within a week
indicate a high risk of stroke
What causes a TIA?
Thrombus or occlusion of vessel
When should TIA be suspected?
sudden-onset, focal neurological deficit that resolves spontaneously and cannot be explained by another condition
What are the key presentations of a TIA?
Sudden onset
Brief duration
Focal neurological deficit
What investigations should be done for a suspected TIA?
AFTER deemed not a stroke
- Blood glucose (rule out other cause for symptoms)
- FBC and platelets (rule out other cause, e.g. infection)
- PT, INR, APTT
- ECG
- Serum electrolytes
- fasting lipid profile
What are the differentials of TIA?
STROKE
Hypoglycaemia
Syncope
Seizure with post-seizure (Todd’s) paralysis
Complex migraine
Space-occupying lesion (intracranial haemorrhage, abscess, or mass)
Functional neurological disorder
Labyrinthine disorders
MS
Peripheral neuropathy
How should a TIA be managed?
Give a loading dose of aspirin immediately, unless contraindicated, to patients with suspected TIA
Once confirmed give secondary antiplatelet prevention, e.g. aspirin + clopidogrel
Complications of a TIA
Stroke
MI
What should be involved in secondary prevention after a TIA?
Risk factor modification (including blood pressure control and smoking cessation)
Managing comorbidities that predispose patients to stroke
What are the different pathological subtypes of ischaemic stroke according to the TOAST classification?
Large vessel disease
Small vessel disease
Cardioembolic
Unknown (cryptogenic)
Rare causes e.g. dissection, CVST, vasculitis
What are the potential mechanisms for ischaemic stroke?
Embolism: an embolus originating somewhere else in the body causes obstruction of a cerebral vessel, resulting in hypoperfusion to the area of the brain the vessel supplies.
Thrombosis: a blood clot forms locally within a cerebral vessel (e.g. due to atherosclerotic plaque rupture).
Systemic hypoperfusion: blood supply to the entire brain is reduced secondary to systemic hypotension (e.g. cardiac arrest).
Cerebral venous sinus thrombosis: blood clots form in the veins that drain the brain, resulting in venous congestion and tissue hypoxia.
How does the Bamford (oxford) classification system describe ischaemic strokes?
Partial Anterior Circulation Infarction
Total anterior circulation infarction
Posterior Circulation Infarction
Lacunar Infarction
Where does a total anterior cerebral infarction affect and how does it present?
affecting the areas of the brain supplied by both the middle and anterior cerebral arteries
All 3 present:
- Unilateral weakness (and/or sensory deficit) of the face, arm and leg
- Homonymous hemianopia
- Higher cerebral dysfunction (dysphasia, visuospatial disorder)
Where does a partial anterior cerebral infarction affect and how does it present?
only part of the anterior circulation has been compromised.
Two of the following need to be present for a diagnosis of a PACI:
- Unilateral weakness (and/or sensory deficit) of the face, arm and leg
- Homonymous hemianopia
- Higher cerebral dysfunction (dysphasia, visuospatial disorder) - this alone is enough for diagnosis
Where does a posterior cerebral infarction affect and how does it present?
involves damage to the area of the brain supplied by the posterior circulation (e.g. cerebellum and brainstem).
One of the following need to be present for a diagnosis of a POCI:
- Cranial nerve palsy and a contralateral motor/sensory deficit
- Bilateral motor/sensory deficit
- Cerebellar dysfunction (e.g. vertigo, nystagmus, ataxia)
- Isolated homonymous hemianopia
Where does a lacunar stroke affect and how does it present?
subcortical stroke that occurs secondary to small vessel disease. There is no loss of higher cerebral functions (e.g. dysphasia).
One of the following needs to be present for a diagnosis of a LACS:
- Pure sensory stroke
- Pure motor stroke
- Sensori-motor stroke
- Ataxic hemiparesis
What % of strokes are ischaemic?
87%
What sudden focal neurological symptoms would be seen in stroke?
Unilateral weakness or paralysis in the face, arm, or leg
Unilateral sensory loss
Dysarthria or expressive or receptive dysphasia
Vision problems (e.g., hemianopia)
Headache (sudden severe and unusual headache)
Difficulty with coordination and gait
Vertigo or loss of balance
What are the risk factors for ischaemic stroke?
Age ≥55 years
Hx of TIA or ischaemic stroke
family hx of stroke at a young age
Hypertension
Smoking
Diabetes mellitus
Atrial fibrillation
Comorbid cardiac conditions
Carotid artery stenosis
Sickle cell disease
Dyslipidaemia
What should be the first investigation done for stroke?
Non-contrast CT head