Pathophysiology Flashcards
What can cause haemorrhagic stroke?
Ruptured Aneurysm
Head Trauma (Generally Subarachnoid or Intracerebral)
Dissection - carotid
What are the 2 types of stroke?
Haemorrhagic
Ischaemic
What are 3 forms of ischaemic stroke?
Cerebral Thrombosis
Cerebral Embolism - Thromboembolism, Fat Embolism, Air embolism
Lacunar stroke
What are some symptoms of stroke?
Weakness/Paralysis or numbness on contralateral side Vertigo/dizziness Headache Visual loss/blurred vision Faintness Confusion Speech problems Difficulty swallowing Cognitive problems Memory problems Consciousness alterations
What does FAST stand for in terms of stroke?
Facial weakness
Arm weakness
Speech problems
Time to call 999
What is the immediate stroke management plan?
FAST Scan – ischaemic or haemorrhagic Blood Tests Clot-Busting (4.5hr window) or haemorrhage evacuation Chest X-rays, ECG, Ultrasound
Which scans are best for each type of stroke?
CT – fast, easy to spot haemorrhage
DWI – best for ischaemic damage
Describe thrombolysis use in stroke management
Intravenous (IV) rtPA (Alteplase) within a 4.5hr window
Often stroke onset time unknown
If large clot burden, IV tPA poor response
Intra-arterial (IA) thrombolysis possible
Interventional neuroradioradiolgy - Endovascular thromboaspiration, Microcatheters can directly reach the thrombus
In which arteries might clot burdens be large?
Terminal carotid/proximal MCA and basilar
What are the 4 main types of CNS syndromes/infarct?
TACS (TACI) – Total Anterior Circulation Syndrome (ACA, MCA)
PACS (PACI) – Partial Anterior Circulation Syndrome
LACS (LACI) – Lacunar Syndrome
POCS (POCI) – Posterior Circulation Syndrome
What symptoms occur with Total Anterior Circulation Infarct?
Higher Dysfunctions Dysphasias Visuospatial problems Homonymous Hemianopia Motor/Sensory Deficits
What symptoms will lacunar infarcts produce?
Focal changes
Pure Motor or Sensory or Sensorimotor loss
Ataxic Hemiparesis
What symptoms occur with posterior circulation infarct?
Cranial nerve palsy & contralateral motor/sensory deficit
Bilateral motor or sensory deficit
Cerebellar signs
Eye Movement deficits/isolated homonymous hemianopia
What are cerebellar signs?
DANISH Dysdiadokinesia & dysmetria (overshoot) Ataxia Nystagmus Intention tremor Slurred speech Hypotonia
What are lacunar infarcts?
Small lesions – lake-like cavities, giving focal deficits
Common in brainstem regions and deep cerebral white matter
Occlusion of small vessels: Lenticulostriate, Thalamogeniculate
Brainstem perforating vessels
What are watershed infarcts?
Systemic hypotension causing infarct in areas of overlap of supply
Most common ACA-MCA infarct caused by occlusion of carotid artery
Man in a barrel- loss of trunk sensation/motor function and aphasia
MCA-PCA affects visual processing
Where are spinal watershed areas?
T4-T8 – watershed between radicular arteries (thoracic and great radicular artery)
L1 – watershed between Great radicular artery and ascending sacral arteries
What are main causes for adolescent strokes?
Hereditary CHD/AHD Congenital Abnormalities Trauma Infection Metabolic Neoplasia
What are transient ischaemic attacks?
Mini-Stroke, usually results from drop in perfusion, often: Carotid Artery Insufficiency, Vertebrobasilar Insufficiency
Symptoms same as Full Stroke
Amourosis fugax - loss of blood flow to retina
Severe symptoms for <30 mins
Full recovery within 24
Use it as a WARNING SIGN
How do you calculate the risk of stroke after a TIA?
ABCD2
A — Age: > 60 years, 1 point
B — BP: >140/90 mmHg, 1 point
C — Clinical features: unilateral weakness, 2 points; speech problems but no weakness, 1 point
D — Duration of symptoms: ≥ 60 mins, 2 points; 10–59 mins, 1 point
D — Diabetes: 1 point
Score ≥4, high risk of stroke
2 TIAs in close succession – high risk (even if ABCD2 <3)
1:10 TIAs with no treatment will have full stroke within 1 year
What assessment score is used for stroke risk in a patient with AF?
CHADVASC scale if patient has AF
What members of the MDT could be required in post stroke management?
Consultant physicians nurses physiotherapists occupational therapists speech and language therapists clinical psychologists rehabilitation assistants social workers
What are mortality rates post stroke?
20% mortality within first month
10% mortality within year
Rest recover but ~50% have disability
Recurrence rate 30-43%
What is post stroke pain?
Thalamic pain Occurs 1 week- 6 months after stroke
Can occur anywhere in spinothalamic system
Generally occlusion of thalamo geniculate arteries
Symptom (referred to contralateral side): Burning pain with sharp components, Hyperalgesia & Allodynia, Treat as for neuropathic pain (Amitriptyline)
What is vascular dementia?
Many vascular CNS events, including stroke
Multi-infarct dementia - from many small TIA
Single-infarct dementia - related to large stroke
Lacunar infarct – variable depending on size
Biswanger’s dementia – multiple lacunar infarcts caused by
arteriosclerosis of subcortical vessels
Multi-infarct dementia linked to step-wise progression in cognitive decline
Lifestyle changes/BP can prevent
Early detection vital
Early signs: vascular cognitive impairment, Slow thought, Difficulties planning, Speech impairment, Mood and behaviour changes, often mistaken for depression
Which patients are susceptible to sub dural haemorrhages?
Elderly and alcoholic
Due to neural shrinkage, bridging veins are under increased tension
What is a likely cause of a sub arachnoid haemorrhage?
Bleed here is from cerebral artery aneurysm
What can a meningioma lead to?
Can produce focal symptoms from cortical or cranial nerve compression
Raised ICP may cause multiple deficits, headache or loss of consciousness
What are the two layers of the dura mater?
Periosteal layer
Meningeal layer
Why can Periorbital infection spread from the orbit to the meninges?
Dura and subarachnoid space extend through the optic canal to the posterior of the orbit
Which artery runs past the pterion and is therefore at risk of rupture with a skull fracture?
Middle meningeal - extradural haemorrhage
What is a risk with an extradural haematoma?
Lucid period - patient will regain consciousness, seem fine and then suddenly collapse when pressure builds up
What innervates dura in the posterior cranial fossa?
And what clinical significance does this have?
Cervical spinal nerves
Compression of cervical nerves in neck can cause referred pain headache in occipital lobe
What carries sensory info from the meninges?
Trigeminal nerve (CN V) - Innervates a large amount of dura including the tenotoria CN V Also innervates face, sinuses and teeth – referred pain headaches possible
What feature allows rapid drainage of dural venous sinuses?
Valveless and endothelial lined
Where does the sigmoid sinus drain into?
Through jugular foramen
Into internal jugular vein
What drains the scalp?
Emissary veins through cranial bones to superior sagittal sinus
Where do periorbital veins drain?
Cavernous sinus. Form a route for orbital/nasal region infection spread
What is the Glasgow outcome score?
- Dead
- Vegetative state (sleep/wake cycle but not sentient)
- Severely Disabled (conscious but dependent)
- Moderately disabled (independent but disabled)
- Good recovery (may have minor sequelae)
What is diffuse axonal injury?
Trauma causes axon to twist and tear
Result is permanent death of the neuron
What are cardinal features of raised ICP?
Nausea
Papilloedema
Headache