Hamzah's neuro pathology Flashcards
What is an ischaemic stroke?
Blocked artery leads to reduced blood flow to brain –> damage depends on location and time
What is a haemorrhagic stroke?
- artery ruptures and bleeds within the brain
- can be secondary after an ischaemic stroke –> if reperfusion occurs, the dead endothelial cells are likely to rupture
Aetiology of strokes
- atherothrombosis: damaged tunica intima –> atherosclerosis –> fibrous plaque breaks off –> blood clot formation
- emboli: AF, DVT, prosthetic valves
- CNS bleeds: HTN, trauma
- shock or sepsis - sudden decrease in BP
- vasculitis
- anti-phospholipid syndrome
Risk factors for stroke
- FH, HTN, smoking, past TIA, high PCV (haematocrit), high alcohol consumption, increased clotting, PVD, contraceptive pill
Pathogenesis of stroke
- no blood means no nutrients to brain cells
- high sodium in brain cells draws water in via osmosis –> cytotoxic oedema
- high calcium in brain cells –> damages lipids in mitochondria and lysosomes –> degenerative enzymes leak out
- 4-6hrs after infarct - inflammation damages the BBB
Clinical presentation of stroke
- sudden onset
- focal neurological signs relate to distribution of affected artery
- severe headache and coma within hrs
ACA occlusion
limbs affected
MCA occlusion
chin to hip affected
PCA
peripheral vision lost but not macular vision
Cerebral infarcts (50%)
- hemiplegia
- initially flaccid, then spastic muscle
- dysphasia
- homonymous hemianopia
Brainstem infarcts (25%)
- quadriplegia
- disturbances of gaze and vision
- locked in syndrome
lacunar infarct (25%)
- in basal ganglia, internal capsule, thalamus and pons
- 5 different syndromes: ataxic hemiparesis, pure motor, pure sensory, sensorimotos, dysarthria (clumsy hand)
Differential diagnosis of stroke
- Head injury, hypo/hyperglycaemia, subdural haemorrhage, intracranial tumours, hemiplegic migraine, epilepsy, CNS lymphoma
Diagnostic tests for stroke
- FAST
- CT/MRI
- Hypertension - retinopathy and CXR –> big heart
- cardiac source of emboli - ECG –> AF
- cardiac doppler IS and CT/MRI angiography
- vasculitis - ANCA positive (IgG autoantibodies)
Treatment of stroke
- 1st hr
- protect airway, NBM, check pulse, BP and ECG
- blood glucose
- thrombolysis - IV alteplase must be given within 4.5 hrs
- high dose aspirin (inhibits COX1, suppressing prostaglandins and thromboxane synthesis)
- clopidogrel (inhibits platelet aggregation by modifying platelet ADP receptors)
Stroke prevention
Primary prevention
- control risk factors - statins
- exercise
- smoking cessation
- lifelong anticoagulation if left prosthetic heart valves
Secondary prevention
- control risk factors
- antiplatelet agents - clopidogrel
- warfarin if stroke from AF
What is a TIA
- sudden onset of focal CNS phenomenon due to temporary occlusion of part of the cerebral circulation
- symptoms last <24hrs
Aetiology of TIA
- atherothromboembolism (listen for bruits)
- cardiac embolism - AF, valve disease, prosthetic valve
- hyperviscosity - polycythaemia, leucocytosis, myeloma
Carotid territory symptoms of TIA
- amaurosis fugax (painless temporary loss of vision in eye - emboli passes into retinal artery)
- aphasia
- hemiparesis (one sided weakness)
- hemianopic visual loss
Vertebrobasilar territory symptoms of TIA
- diplopia (double vision), vertigo, vomiting
- choking and dysarthria (slurred speech)
- ataxia
- bilateral visual loss
- tetraparesis (all 4 limbs weak)
What is not typical of a TIA
Global events such as syncope or dizziness
Differential diagnosis of TIA
- hypoglycaemia, migraine aura, focal epilepsy, hyperventilation, retinal bleeds
Diagnostic tests for TIA
- FBC, ESR, U&Es, glucose, CXR, ECG, carotid doppler and angiography
Treatment of TIA
Control cardiovascular risks
- BP <140/85, statins, DM, smoking cessation
Antiplatelet drugs - aspirin 300mg then clopidogrel
Warfarin if cardiac source of emboli
Cardiac endarterectomy - removes plaque from inside of internal carotid arteries
