Flashcards in W3 - Cerebrovascular disease Deck (19):
Define the term "cerebrovascular disease" and list 5 predisposing factors.
Definition: Any condition affecting the blood vessels of the brain.
- Age (increasing age)
- Gender (males more common)
- Genetic/Family Hx (increased likelihood)
- Sedentary lifestyle
- Hypertension (high BP)
Briefly discuss the meaning of the terms: "Stroke" and "cerebrovascular accident". In your discussion indicate the preferred terminology for these processes.
Stroke and CVA are commonly used terms that are reasonably unidentifiable/non-specific (provide no information about underlying nature of condition causing neurological deficit). Ischaemic/occlusive stroke and haemorrhagic stroke are the preferred terms, as they indicate the cause and pathophysiology (from which you can derive an appropriate treatment and prognosis etc)..
List the key processes which commonly result in cerebral ischaemia.
- Atherosclerosis (larger arteries, sites of arterial branching or curvature) - causes narrowing of blood vessels
- Thrombosis (commonly carotid sinus/carotid bifurcation) - May result in vascular occlusion
- Embolism - Lodge in cerebral circulation, potentially resulting in cerebral ischaemia and infarction (main causes: myocardial infarction, infective endocarditis, prosthetic cardiac valves, mitral stenosis & associated atrial fibrillation, advanced atherosclerosis)
Less common processes:
- Dissecting aortic aneurysm
- Cerebral vein occlusion
- Vascular trauma
- Hypoxia (respiratory arrest)
- Cardiac arrest/arrhythmia
Define the term "atherosclerosis" and list and discuss the vascular consequences
A disease of the arteries characterised by the build-up of fatty tissue/cholesterol ("plaques") on their inner walls that may cause occlusion and/or lead to a thrombus/embolus.
- Narrowing of blood vessels
- Thrombosis - May result in vascular occlusion (common in carotid sinus/bifurcation)
- Ulceration - Resulting in release of emboli into circulation
List and briefly discuss the main processes which result in the production of cerebral emboli
- Infective endocarditis - Vegetation of valves of the heart, where friable material may break off to form emboli
- Prosthetic cardiac valves - Mechanical trauma may displace, causing embolism
- Mitral stenosis (causing atrial fibrillation) - Lack of contraction causes blood to pool --> increases risk of coagulation and consequently embolism
- Advanced atherosclerosis - Breaking off of atherosclerotic plaques causing emboli. Commonly from aortic arch, carotids, Circle of Willis.
Write notes on "Transient Ischaemic Attacks (TIAs)".
Definition: Transient episode of neurological dysfunction caused by focal brain, spinal cord, or retinal ischaemia without acute infarction.
- Conditions resulting in decreased cerebral blood flow in patients with severe atherosclerotic narrowing of cerebral arteries
- Small platelet/cholesterol emboli originating from ulcerated atheroma in cerebral vessels/carotid/aorta
- Small emboli or thrombi from other sources
- Decreased blood flow caused by thrombi/emboli results in ischaemic neurological deficit that reverses as thrombus/embolus is rapidly dissolved and blood flow is returned to normal.
- Indicate severe atherosclerosis in cerebral vasculature
- "Warning sign" - 30% of pt's will suffer cerebral infarction within 5 years.
- Depends on cause
- Includes surgery and anticoagulant medication
List the main clinical manifestations of cerebral infarction.
Signs of increased ICP:
- Headache (diffuse and instant), seizures, vomiting, loss of consciousness
Give four (4) examples of focal (localising) manifestations due to cerebral infarction. In each case name the blood vessel which is involved.
Anterior cerebral artery occlusion:
- Frontal lobe - Personality changes, loss of pupil conjugate gaze, confusion and disorientation
- Motor & sensory cortex - Contralateral weakness (hemiparesis) and sensory loss in the lower limb
Middle cerebral artery occlusion:
- Lateral surface of cerebrum - Hearing loss, balance changes, contralateral hemiparesis and sensory loss (head & upper limb), extinction
- Speech area (dominant hemisphere) - Expressive aphasia (loss of ability to produce speech), aprosodia
- Optic radiation - Contralateral hemianopsia (visual field loss on L or R side of vertical midline)
Posterior cerebral artery occlusion:
- Occipital lobe - Cortical-type vision loss
Vertebrobasilar artery occlusion:
- Cerebellum - Intention tremor, incoordination, hypotonia
Discuss the relative speed of onset of the clinical manifestations of cerebral infarction
Speed with which Ssx appear may indicate underlying aetiology.
- Instantaneous/explosive = haemorrhagic
- Medium = Embolism (slowly pushed deeper)
- Slow = Thrombosis
Briefly outline the treatment of patients suffering from cerebral infarction.
Acute phase - Reducing cerebral oedema and raised ICP. Treatment includes thrombolysis (should be initiated ASAP after onset of Ssx), corticosteroids (reduce inflammation) and diuretics (removal of fluid).
Post-acute phase - Supportive treatment to maintain vital functions.
Chronic stage - Early and intense specialised physical and functional rehabilitation
Discuss the prognosis of cerebral infarction
Haemorrhagic - Likely death
Ischaemic - Better prognosis
- Improvement for ischaemic cells (as blood supply is returned) --> improvement in neurological function
- Necrotic cells will not recover.
- Opportunity for neuroplasticity (neighbouring areas pick up function of infarcted areas)
- May get complete neurological recovery
List the main causes of intracranial haemorrhage.
- Hypertension - Causes spontaneous intracerebral haemorrhage
- Berry aneurysms - Causes spontaneous subarachnoid haemorrhage
- Venous occlusion - Associated with vascular malformation, neoplasms or with bleeding diathesis
Define the term "intra-cerebral haemorrhage"
A non-traumatic haemorrhage from small arteries deep in the brain substance
Discuss the following for intra-cranial haemorrhage:
b) Pathology and pathogenesis
- 80% occur secondary to hypertension
- 10% of all stroke cases
- Most occur >40 years old
- Common sites: Basal ganglia or internal capsule (rupture of lenticulo-striate arteries)
- Very high death rate
b) Pathology and pathogenesis
- Rupture of a microaneurism (Charcot-Bouchard) in the lenticulostriate arteries
- Most devastating type of stroke with greatest mortality rate.
- No clinically proven therapies
- Treatment typically supportive
- FAST - Facial drooping, inability to lift both arms, slurred speech, timing critical
Discuss the events which occur during intra-cerebral haemorrhage
1. Sudden increase in BP
2. Rupture of aneurism (Charcot-Bouchard)
3. Growing blood clot dissects and destroys brain tissue
4. Haematoma, resulting in increased ICP
5. Death (via tentorial hermiation) or recovery (breakdown of blood/breakdown of necrotic tissue/cystic area with reactive gliosis)
Define the term "sub-arachnoid haemorrhage". What is it's main cause?
Non-traumatic haemorrhage resulting from larger arteries, passing through subarachnoid space.
Main cause: Rupture of a berry aneurism (95% of cases)
Write brief notes on "berry aneurisms".
Definition: Saccular aneurisms that arise from congenital defects in the media of cerebral arteries (commonly the Circle of Willis).
- Anterior communicating artery (30%)
- Join between posterior communicating and ICA (30%)
- Middle cerebral artery (10%)
- Basilar artery (10%)
Discuss the events occurring during sub-arachnoid haemorrhage. What is it's prognosis?
1. Rupture of berry aneurism and bleeding into subarachnoid space
- Often leaks before rupture - If this happens, clotting occurs and fusing of berry aneurism to surface of brain --> intra-cerebral haemorrhage
2. Arterial spasm in distal arteries --> cerebral ischaemia and oedema
- Death occurs rapidly (15% of cases) and death risk of recurrence in survivors
- Surgical correction is urgent
- 1/3 of pt's left permanently disabled.