Stroke Syndromes (Etiology & Clinical Features)

7/30/2019 Stroke Syndromes (Etiology & Clinical Features)

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Ischemic Strokes

Thrombosis-most common cause Etiology

Atherosclerotic disease-most common

Vasculitis

Dissection

Polycythemia Hypercoagulable states

Infectious Diseases-HIV, TB, syphilis


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Ischemic Strokes

1/5th due toEmbolism

Etiology

Cardiac

Valvular Vegetations

Mural thrombi- caused by A-fib, MI, or dysrhythmias Paradoxical emboli-from ASD, VSD

Cardiac tumors-myxoma

Fat emboli

Particulate emboliIV drug injections

Septic Emboli


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Ischemic Strokes

Hypo perfusion- less common mechanism

Typically caused by cardiac failure

More diffuse injury pattern vs.thrombosis or embolism

Usually occur in watershed regions of

brain


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Hemorrhagic Strokes

Intracerebral hemorrhage (ICH)- approx. 10% of all strokes

Risk Factors

HTN Increasing Age

Race: Asians and Blacks

Amyloidosis- esp. in the elderly

AVMs or tumors

Anticoagulants/Thrombolitic use

History of previous stroke

Tobacco, and cocaine use


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Subarachnoid hemorrhage (SAH)

Result from rupture of berry

aneurysm or rupture of AVMs

Hemorrhagic Stroke


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Stroke Syndromes

Classic physical exam findings that assist

in localizing the lesion.


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Transient Ischemic Attack (TIA)Neurologic deficit that resolves

within 24 hours

Most TIAs resolve < 30 minutes

Approx. 10% of patients will have astroke in 90 days

Half of these in just 2 days

Ischemic Stroke Syndrome


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Anterior Cerebral Artery InfarctionContralateral weakness/numbness

greater in leg than arm

Dyspraxia

Speech perseveration

Slow responses

Ischemic Stroke Syndromes


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Middle cerebral artery occlusion

Dominant Hemisphere (usually the

left)

Contralateral weakness/numbness in armand face greater than leg

Contralateral hemianopsia

Gaze preference toward side of infarctAphasia (Wernickes -receptive, Brocas -

expressive or may have both)

Dysarthria



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Middle cerebral artery occlusionNondominant hemisphere

Contralateral weakness/numbness in

arm and face greater than in the leg

Constructional Apraxia

DysarthriaInattention, neglect, or extinction


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Posterior Cerebral Artery InfarctOften unrecognized by patient-

minimal motor involvement

Light-touch/pinprick may besignificantly reduced

Visual cortex abnormalities also

minimal



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Vertebrobasilar SyndromePosterior circulation supplies

brainstem, cerebellum, and visual

cortexDizziness, vertigo, diplopia, dysphagia,

ataxia, cranial nerve palsies, and b/l limb

weakness, singly or in combinationHALLMARK: Crossed neurological

deficits: ipsilateral CN deficits with

contralateral motor weakness



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Lateral Medullary (Wallenburg)

Syndrome

Specific post. Circulation infarct involving

vertebrobasilar and/or post inferior

cerebellar Art.

Signs:

Ipsilateral loss of facial pain and temperature with

contralateral loss of these senses over the body Gait and limb ataxia

Partial ipsilateral loss of CN V, IX, X, and XI

Ipsilateral Horner Syndrome may be present


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Basilar Artery Occlusion

Severe quadriplegia

Coma

Locked-in syndrome-complete muscleparalysis except for upward gaze


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Cerebellar Infarction-subset of post. circ.infarcts

Symptoms: drop attack with sudden inability to walk or

stand, often a/w vertigo, HA, nausea/vomiting, neck pain

Diagnosis: MRI, MRA as bone artifactobscures CT

Cerebral edema develops w/in 6-12 hrs

increased brainstem pressure and decreasedLOC

Treatment: decrease ICP and emergent

surgical decompression


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Lacunar Infarction

Infarction of small penetrating arteries inpons and basal ganglia

Associated with chronic HTN present in 80-

90% Pure motor or sensory deficits

Arterial Dissection

Often a/w severe trauma, headache, andneck pain hours to days prior to onset ofneuro symptoms

HTN risk factor for spontaneous dissection

Ischemic Stroke Syndrome


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Blood Supply to the Medulla

The Medulla is supplied by the;

1. Anterior spinal artery, sends blood to the paramedianregion of the caudal medulla.

2. Posterior spinal artery, supplies rostral areas, including

the gracile and cuneate fasiculi and nuclei, along withdorsal areas of the inferior cerebellar peduncle.

3. Vertebral artery, bulbar branches supply areas of both

the caudal and rostral medulla.

4. Posterior inferior cerebellar artery, supplies lateralmedullary areas.


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Stroke syndromes - MedullaOcclusion of branches of the anterior spinal artery will

produce a inferior alternating hemiplegia (akamedial

medullary syndrome),characterized by;

1. Acontralateral hemiplegia of the limbs, due to

damage to the pyramids or the corticospinal fibers

2. A contralateral loss of position sense, vibratory sense

and discriminative touch, due to damage to the medial

leminiscus

3. An ipsilaterally deviation and paralysis of the tongue,

due to damage to the hypoglossal nucleus or nerve


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S k d M d ll


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Stroke syndromes - MedullaOcclusion of the posterior inferior cerebellar artery (or

contributing vertebral) will produce a lateral medullary

syndromeorWallenbergs syndrome, characterized by

1. A contralateral loss of pain and temperature sense, due to

damage to the anterolateral system (spinothalamic tract)

2. An ipsilateral loss of pain and temperature sense on the face,due to damage to the spinal trigeminal nucleus and tract

3. Vertigo, nausea and vomiting, due to damage to the vestibular

nuclei

4.Hornors syndrome, (miosis [contraction of the pupil], ptosis[sinking of the eyelid], decreased sweating), due to damage to

the descending hypothalamolspinal tract


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Bl d S l t th P


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Blood Supply to the Pons

S k d P


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Stroke syndromes - PonsObstruction of the paramedian pontine arteries will produce amiddle alternating hemiplegia (also termed medial pontine syndrome)which is characterized by;

1. Hemiplegiaof the contralateral arm and leg, due to damage to thecorticospinal tracts

2. Contralateral loss of tactile discrimination, vibratory and position

sense, due to damage to the medial leminiscus

3. Ipsilateral lateral rectus muscle paralysis, due to damage to theabducens nerve or tract (can cause diplopia double vision)

St k d P


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Stroke syndromes - Pons

Occlusions of long branches circumferential branches ofthe basilar artery produce a lateral pontine syndrome,

characterized by;1. Ataxia, due to damage to the cerebral peduncles (middle andsuperior)2. Vertigo, nausea, nystagmus, deafness, tinnitus, vomiting, due todamage to vestibular and cochlear nuclei and nerves

3. Ipsilateral pain and temperature deficits from face, due to damage tothe spinal trigeminal nucleus and tract4. Contralateral loss of pain and temperature sense from the body, dueto damage to the anterolateral system (spinothalamic)5. Ipsilateral paralysis of facial muscles and masticatory muscles, due

to damage to the facial and trigeminal motor nuclei (cranial nervesVII and V)


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Bl d S l t th Midb i


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Blood Supply to the MidbrainThe major blood supply to the midbrain is derived from branchesof the basilar artery;1. Posterior cerebral artery, forms a plexus with the posterior

communicating arteriesin the interpeduncular fossa, branches from thisplexus supply a wide area if the midbrain

2. Superior cerebellar artery, supplies dorsal areas around thecentral gray and inferior colliculus with support from branches ofthe posterior cerebral artery.

3. Quadrigeminal, (some posterior choroidal) a branch of the posteriorcerebral, provides support for the tectum (superior and inferior colliculus)

4. Posterior communicating artery, derived from the internal carotid,joins the posterior cerebral to form portions of the circle of Willis

(arterial circle). Contributes to the interpeduncular plexus

5. Branches of these arteries are best understood when grouped intoparamedian, short circumferentialand long circumferential

St k d Midb i


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Stroke syndromes- Midbrain

Occlusion of midbrain paramedian branches

produces a medial midbrain or superioralternating hemiplegia (or Webers syndrome)characterized by;

1. Contralateral hemiplegia of the limbs, andcontralateral faceand tongue due to damage to the descending

motor tracts (crus cerebri).

2. Ipsilateral deficits in eye motor activity,caused by damage to the oculomotor nerve


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Other Clinical Points


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Other Clinical Points

Substantial infarcts within the Pons are generally rapidly fatal,due to failure of central control of respiration

Infarcts within the ventral portion of the Pons can produceparalysis of all movements except the eyes. Patient is consciousbut can communicate only with eyes. LOCKED-IN-SYNDROME

Focal ischemia


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Focal ischemia

Focal ischemia


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Focal ischemia

Focal ischemia


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Focal ischemia

Focal ischemia


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Focal ischemiaWatershed infarcts

H h i S d


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Intracerebral Hemorrhage

ICHsudden onset HA, N/V, elevated BP

Progressive focal neurologic deficits over

minutes

Patients may rapidly deteriorate

Exertion commonly triggers symptoms

Bleeding localized to Putamen, thalamus,pons-pinpoint pupils, and cerebellum

Hemorrhagic Syndromes


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Hemorrhagic Syndromes

Cerebellar Hemorrhage Sudden onset dizziness, vomiting, truncal

ataxia, inability to walk

Possible gaze palsies and increasing stupor Treatment: urgent surgical decompression

or hematoma evacuation


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Hemorrhagic Syndrome

Subarachnoid hemorrhage

Severe HA, vomiting, decreasing LOC

HA- often occipital or nuchal in

location Sudden onset of symptomshistory

may reveal activities a/w HTN such as

defecation, coughing or intercourse


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Stroke Syndromes (Etiology & Clinical Features)

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