W3 - Cerebrovascular disease Flashcards Preview

Neuropathology Tutorial Questions Weeks 1-4 > W3 - Cerebrovascular disease > Flashcards

Flashcards in W3 - Cerebrovascular disease Deck (19):
1

Define the term "cerebrovascular disease" and list 5 predisposing factors.

Definition: Any condition affecting the blood vessels of the brain.

Predisposing factors:
Non-modifiable
- Age (increasing age)
- Gender (males more common)
- Genetic/Family Hx (increased likelihood)
Modifiable
- Overweight/obesity
- Smoking
- Diabetes
- Sedentary lifestyle
- Hypertension (high BP)

2

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)..

3

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
- Vasculitis
- Cerebral vein occlusion
- Vascular trauma
- Hypoxia (respiratory arrest)
- Cardiac arrest/arrhythmia

4

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.

Vascular consequences:
- Narrowing of blood vessels
- Thrombosis - May result in vascular occlusion (common in carotid sinus/bifurcation)
- Ulceration - Resulting in release of emboli into circulation

5

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.

6

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.

Causes:
- 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

Mechanisms:
- 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.

Significance:
- Indicate severe atherosclerosis in cerebral vasculature
- "Warning sign" - 30% of pt's will suffer cerebral infarction within 5 years.

Treatment:
- Depends on cause
- Includes surgery and anticoagulant medication

7

List the main clinical manifestations of cerebral infarction.

Signs of increased ICP:
- Headache (diffuse and instant), seizures, vomiting, loss of consciousness

8

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

9

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

10

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

11

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

12

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

13

Define the term "intra-cerebral haemorrhage"

A non-traumatic haemorrhage from small arteries deep in the brain substance

14

Discuss the following for intra-cranial haemorrhage:
a) Aetiology
b) Pathology and pathogenesis
c) Prognosis

a) Aetiology
- 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

c) Prognosis
- 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

15

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)

16

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)

17

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).

Sites:
- Anterior communicating artery (30%)
- Join between posterior communicating and ICA (30%)
- Middle cerebral artery (10%)
- Basilar artery (10%)

18

Discuss the events occurring during sub-arachnoid haemorrhage. What is it's prognosis?

Events:
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

Prognosis:
- 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.

19

Discuss the clinical manifestations of sub-arachnoid haemorrhage.

- Headache (sudden, severe, bursting)
- Vomiting
- Neck pain
- Rapid loss of consciousness
- Marked neck stiffness (meningeal irritation)
If more severe: Ssx of increased ICP, papilloedema