MODULE 16: CEREBROVASCULAR ACCIDENTS

CEREBROVASCULAR ACCIDENTS

→ abrupt onset or neurological deficit attributable to a focal vascular cause 

• Involving sudden focal disruption of blood flow → brain

ISCHAEMIC

→ clot

→ blood clot: blocks blood flow to a certain part of the bran that leads to cell death

→ artery occlusion leading to an infarct 

• Infarct = dead tissue 

→ loss of oxygen in a specific brain region for more than 3-5 minutes =  cell death = necrosis

→ Where: circle of willis

HEMORRHAGIC

→ rupture

→ blood vessles disintegrate causing bleeding around the brain

THROMBUS

Blood clot 

EMBOLUS

Piece of blood clot traveling through the vein, more dangerous

CRYPTOGENIC

No clear source

CARDIOEMBOLISM

→ embolus originated as cardiac thrombus from atrial fibrillation, rheumatic heart disease

→ heart problem

LACUNAR INFARCTS (SMALL VESSEL STROKE)

→ infarction following occlusion of small arteries supplying the deep cortical structures

→ symptoms depend on the part of the brain affected

LARGE-VESSEL ATHEROSCLEROSIS

→ plaque build up in intra/extracranial arteries 

→ may be due to fatty diet

INTRACEREBRAL HEMORRHAGIC STROKE

→ artery ruptures within the brain 

→ high fatality rate 

→ commonly affected areas: cerebral lobes, basal ganglia, thalamus, brainstem, cerebellum 

→ issues after recovery: barriers against significant recovery d/t rapid cell death that clogs up the skull

SUBARACHNOID HEMORRHAGIC STROKE

→ bleeding into subarachnoid space 

→ bleeding causes hematoma 

→ causes: head trauma, ruptured aneurysm, arteriovenous malformation 

→ pain: bleeding becomes a mass that compresses CSF → adds intracranial pressure to the brain, the blood mass facilitates necrosis

TRANSIENT ISCHAEMIC ATTACK

→ embolus creates a temporary blockage that resolves itself without intervention: within 24 hours, 

• onset: visual disturbance, difficulty walking, motor coordination problem, slurred speech 

→ leaves no evidence in neuroimaging 

→ increases risk for another stroke

COMPUTED TOMOGRAPHY SCAN (CT)

→ uses x-ray; be wary of exposure to radiation, specially to pregnant 

→ presence or absence of subarachnoid hemorrhage

→ inefficient against small infarcts

MAGNETIC RESONANCE IMAGING (MRI)

→ use of magnetic and radiofrequency waves to create brain pictures

→ showing hemorrhages in different stages; enabling the assessment of bleeding onset

→ CT for detecting acute and subacute hemorrhages

→ more efficient in ischaemic strokes

→ small and large vessel region

MODIFIABLE FACTORS

→ hypertension  → cigarette smoking → dyslipidemia → diabetes → abnormal obesity

→ excessive alcohol consumption → lack of physical activity → cartoid/artery disease  → hormone replace therapy → oral contraceptive use

NON-MODIFIABLE FACTORS

→ history of stroke

→ sex: female > males

→ race/ethnicity

→ advanced age

→ family history of stroke

BALANCE, EYES, FACE, ARMS, SPEECH, TIME

BE FAST

OTHER SYMPTOMS

→ hemiparesis/hemiplegia  → sudden severe headache → intense dizziness, nausea, vomiting → anosognosia  → loss of consciousness

→ confusion, disorientation, memory loss → visual disturbances in one/both eyes  → loss of balance, coordination, or walking ability  → speech changes (= dysarthria, aphasia, AOS) → dysphagia

RTPA (RECOMBINANT TISSUE PALSMINOGEN ACTIVATOR)

→ standard of care for acute ischaemic stroke

→ exclude hemorrhage or previous history of stroke/severe head trauma in the past 3 months

THROMBOLYSIS-IN-SITU

→ intra-arterial IV medication to the thrombus 

→ used for large occlusions

MECHANICAL THROMBECTOMY

→ use of stent retriever removing intra-arterial thrombus/embolus

ORAL ANTI-PLATELET

→ prevents platelet aggregation

ANTICOAGULANTS

→ blood thinners that prevent clogging

→ acute stage d/t > risk of hemorrhage

INTRACRANIAL HEMORRHAGE

→ goal: to relieve pressure caused by bleeding 

→ anticoagulants and antiplatelet drugs are contraindicated 

→ surgical evacuation is often an option 

SUBARACHNOID HEMORRHAGE

→ craniotomy to relieve intracranial pressure and attach a metal clip on the aneurysm’s base to deflate it 

→ endovascular microcoil embolization: platinum coil is placed in the aneurysm through a catheter passing from the femoral artery, filling aneurysm preventing blood flow

endovascular microcoil embolization

platinum coil is placed in the aneurysm through a catheter passing from the femoral artery, filling aneurysm preventing blood flow

PROGNOSIS AND RECOVERY

Ischaemic stroke > better prognosis than hemorrhagic stroke

Mortality rate increases with age

Spontaneous recovery refers amount of improvement determined solely by time

Most improvement occurs within the first 3-4 mos  → emphasizing the need for early rehabilitation and interprofessional collaboration

Extent of recovery varies according to time post onset ACUTE: up to 2 wks after SUBACUTE: 3-6 mos CHRONIC: >9 mos

What may limit brain’s neuroplasticity  → depends on severity of stroke  → dead tissue spread if function is not carried over

ACUTE

up to 2 wks after

SUBACUTE

3-6 mos

CHRONIC

>9 mos

50%

→ ischaemic stroke patients with moderate or severe hemiplegia 

→ most with milder deficits will have preserved sensorium and eventually progress with ADLs

25%

→ recover from a first stroke is most likely to have another stroke within 5 years

35% - 45%

→ patients with intracranial hemorrhagic stroke die within the first month

35%

→ die after the first aneurysmal subarachnoid hemorrhage 

• Another 15% die within a few week because of a subsequent rupture