Neuro PT1- Stroke

Stroke Statistics

5th leading cause of death in US 1 in 6 deaths due to stroke Leading cause of long-term disability (50% have hemiparesis after 6 months, 30% still need assist to ambulate) 75% first stroke, 25% recurrent Every 40 seconds lifetime risk in US is 24.9% of time

Modifiable risk factors

HTN Arteriosclerosis tobacco use diabetes high cholesterol physical inactivity obesity history of TIA atrial fibrillation excessive alcohol use illegal drug use

Non-modifiable risk factors

increasing age (chances double every decade after 55) gender: men except 35-44 and >85 heredity race African Americans and Hispanic Americans history of stroke

Warning signs of a stroke

Sudden numbness or weakness of the face, arm, or leg - especially on one side; Sudden confusion, trouble speaking, or understanding; Sudden trouble seeing in one or both eyes; Sudden trouble walking, dizziness, loss of balance or coordination; Sudden, sever headaches with no known cause

Ischemic stroke

obstructed vessel result in poor blood flow to a region of the brain

Hemorrhagic stroke

ruptured blood vessel resulting in bleeding in the brain

Ischemic: epidemiology

87% of strokes cerebral thrombosis cerebral embolus conditions resulting in low systemic perfusion pressure

Hemorrhagic: epidemiology

13% intracerebral subarachnoid saccular anerysm arteriovenous malformation

Which type of stroke is associated with overall higher mortality in the first 3 months?

Hemorrhagic After 3 months, there is no correlation between stroke type and mortality. Survival is negatively impacted by increased age.

Stroke recurrence:

stroke survivors are as a significantly higher risk of another stroke than general pop. 30 days- 3.1% 1 year- 11.1% 5 years- 26.4% 10 years- 39.2%

Arteries most commonly impacted by an ischemic stroke

MCA- 51% Small vessel: 13% Brainstem- 11% 1 Teritory- 9% PCA- 7% ACA- 5% Cerebellar 4%

Atherosclerotic plaques that form in the brain over time and block blood flow describes what?

Cerebral thrombosis

Two subcategories of cerebral thrombosis

large vessel small vessel

Large vessel thrombosis

MCA, carotid artery

Small vessel thrombosis

Lacunar stroke due to blockage of lenticulostriate arteries, medullary arteries, etc.

A clot that travels to the brain and blocks blood flow describes what?

Cerebral embolus

What is the most common source of an emboli?

heart due to afib, valvular disease, etc.

additional sources for an emboli?

internal carotid artery: clot originates at bifurcation of common carotid artery.

Ischemic lesions that occurs in locations at the junction between 2 main arterial territories describes?

watershed stroke

Watershed strokes can occur from? What causes them?

low systemic perfusion pressure

low systemic perfusion pressure can result from?

cardiac arrest shock etc.

Common locations for low systemic perfusion pressure include:

cortical border zone: between ACA and MCA internal border zone: between LCA and MCA Cortical border zone: between MCA and PCA

What is the region surrounding the core ischemic zone known as?

ischemic penumbra

What is the target area for pharmacological management and neuroplasticity after an ischemic stroke?

Ischemic penumbra

Describe severe ischemia in the core ischemic zone

blood flow below 10-25% results in death of neurons and glial cells

Description of crescendo TIA

2 occurrences within 24 hours or 3 occurrences within 3 days or 4 occurrences within 2 weeks

Describe a transiet ischemic attach

complete resolution of symptoms within 24 hours warning sign for a major stroke.

Risk factors for an ischemic stroke include:

previous stroke or TIA HTN Diabetes HD/Afib Obesity Hypercholesterolemia Physical inactivity Oral contraceptives Excessive alcohol intake

Risk factors for a hemorrhagic stroke include:

Hypertension alcohol and drug abuse use of anticoagulants

Intracerebral hemorrhage: common locations

basal ganglia, cerebellum, brainstem, cortex

Intracerebral hemorrhage can lead to

unconsciousness or death

Rupture of blood vessels between the brain and the skull describe?

subarachnoid hemorrhage

subarachnoid hemorrhage: symptoms

sudden, intense headache, neck pain, nausea and vomiting, thunderclap headache

What is a common cause of a subarachnoid hemorrhage?

cerebral aneurysms (85%)

Rounded or irregular swellings in arteries that are less resistant to changes in pressure describe?

saccular aneurysm

saccular aneurysm: common locations

sites of vessel bifurcation where shear forces against arterial wall are greatest.

Congenital defect consisting of an abnormal tangle of blood vessels describes:

arteriovenous malformation

What is the most common diagnosis option for stroke?

CT Inexpensive, can differentiate between ischemic and hemorrhage, gives time to give medicine if done fast enough for ischemic stroke. widely available and quickly performed.

A minimally invasive study involving injection of intravenous contrast followed by radiography.

Computed tomography angiogram

Computed tomography angiogram provides clear images to identify

stenosis, occlusions, aneurysms, and vascular abnormalities

Downfall of MRI

can take up to one hour to complete. cannot be used in patients with pacemakers and some metallic implants.

Benefits of MRI

detects edema in the sub-acute phase of stroke that may not be visible on CT scan

Magnetic resonance angiogram benefits:

can detect high grade atherosclerotic lesions and less common causes of ischemic stroke (venous thrombosis, artery dissection). Can be based on the number of visible blood vessels compared bilaterally.

What imaging is used to determine areas of tissue where ischemia is reversible?

positron emission tomography (PET) allows imaging of regional blood flow and cerebral metabolism.

Reading a PET scan:

high brain activity in red/yellow low brain activity in blue

Ischemic stroke: medical interventions

tPA Mechanical thrombectomy antiocagulation therapy antiplatelet therapy blood pressure is usually not reduced (termed "permissive hypertension" to maintain perfusion)

What is the gold standard for treating ischemic strokes?

tPA: tissue plasminogen activator

When should tPA be administered?

within 3 hours of symptoms onset up to 4 1/2 hours in some patients.

must meet a specific criteria, including no signs of hemorrhage

Removal of clot with a corkscrew device describes:

mechanical thrombectomy

Medications for ischemic stroke

anticoagulation therapy heparin (lovenox) Warfarin (coumadin) antiplatelet therapy aspirin, etc.

Medical interventions: hemorrhage stroke

cease antiplatelet and/or anticoagulant therapies normalize blood pressure decrease intracranial pressure may surgically clip aneurysm

What artery is located between the branches of the deep PCA and MCA?

anterior chordal artery

Where is the most common location of stroke?

MCA

MCA supplies what?

primary motor and sensory cortices (head, neck, trunk, arm), Broca's area, Wernicke's area

Clinical presentation of MCA stroke

Contralateral weakness, sensory impairment

L MCA specifically results in

aphasia

R MCA specifically results in

neglect and apraxia

Lacunar stroke description

deep branches of the MCA (lenticulostriate arteries)

Lacunar stroke: supplies

basal ganglia and the internal capsule

Lacunar stroke: incidence

high in individuals with HTN and the elderly

Lacunar strokes: presentation

contralateral weakness (no sensory loss) or sensory loss without weakness. one or the other. ataxia facial weakness: tongue and larynx problems with fine motor "clumsy hand"

PCA supplies

occipital lobe, inferior part of the temporal lobe, deep structures (diencephalon)

PCA: clinical presentation

contralateral homonymous hemianopsia, sensory impairments, weakness. prosopagnosia alexia aphasia

ACA supplies

primary motor and sensory cortices (lower limb), supplemental motor area, prefrontal cortex

ACA presentation

Rare Contralateral weakness, sensory impairment frontal lobe behavioral abnormalities (poor judgement, decreased attention, decreased motivation, difficulty regulating emotions)

Posterior inferior cerebellar artery stroke AKA

wallenberg syndrome or lateral medullary syndrome

Posterior inferior cerebellar artery: supplies

cerebellum, medulla

Posterior inferior cerebellar artery: Clinical presentation

sensory impairment: loss of pain and temp on contralateral side of the body and ipsilateral face. spinothalamic tract

ataxia dizziness/vertigo ataxia diplopia dysphagia dysarthria horner's syndrome

Horner's syndrome causes?

by damage to the sympathetic trunk lateral to vertebral bodies.

Horner's syndrome: causes

miosis ptosis decreased sweating

anterior inferior cerebellar artery: supplies

cerebellum, cranial nerves VII and VIII

anterior inferior cerebellar artery:

collection of symptoms called lateral pontine syndrome

ipsilateral ataxia contralateral weakness, sensory impairment (pain and temp) dizziness/vertigo

Impairment categories in individuals with stroke

sensation motor function perceptual deficits communication swallowing deficits cognition

Sensory impairments

light touch, proprioception, pain, temp pain visual field deficits

Thalamic pain syndrome

damage to thalamus presents as numbness that evolves into an often debilitating burning sensation. allodynia (pain evoked by a stimulus that would not normally be painful)

Visual field:

Optic nerve-> optic chiasm-> optic tract

Optic chiasm lesions aka

bitemporal hemianopsia

optic nerve lesion aka

blindness

optic tract lesion

homonymous hemianopsia

Tone is present due to

intrinsic factors (mechanical/elastic stiffness of mm) neural factors (reflexive mm contraction or change in inhibition/excitation) abnormal tone can be hypertonia or hypotonia

Rigidity: hypertonia

resistance through entire ROM independent of velocity

Cogwheel rigidity

resistance followed by giving way in step-like movements

lead pip rigidity

constant resistance

dystonia

repetitive and patterned abnormal mm contractions (not normally seen in stroke)

perceptual disorders

unilateral neglect lateropulsion agnosia spatial relations disorders apraxia

unilateral neglect most often occurs after damage to the?

posterior inferior parietal lobe on the R side

Why is left hemispatial neglect more common?

L side only gets input from left hemisphere R side gets input from left and right hemisphere. R side can compensate for damage of L side.

There is not compensation for damage to the right hemisphere.

Pusher syndrome

unaffected limbs always push towards the affected side. Usually 18 degrees.

agnosia

lack of awareness

anosagnosia

denial of symptoms often presents in patients with neglect, but not always associated with damage to the right posterior insula

somatopagnosa

autopagnosia or body image agnosia lack of awareness of body structure and relationship of body parts to one another in self and other cannot pint to a body part or mimic a movement associated with damage to the left parietal or poserior temporal lobe

finger agnosia

inability to recognize, name, select, and differentiate their own or another's fingers poor hand dexterity (like 3 digits are fused together)

right-left discrimination disorder

inability to identify right and left side of self, other and enviornment

agnosia: classifications/types

anosagnosia somatopagnosa finger agnosia right-left discrimination disorder

Gerstmann syndrome

Damage to parietal lobe R-L discrimination finger agnosia agraphia acalculia

Spatial relations disorder

failure ground discrimination spatial relations topographic disorientation

apraxia

inability to perform particular purposeful movements despite adequate strength, coordination, and sensation

apraxia types:

ideational and ideomotor

ideomotor

difficulty planning and completing actions on command BUT often able to perform actions automatically

A performance problem

ideational

inability to conceptualize and perform tasks, either on command or automatically.

conception problem