Stroke Syndromes (Etiology & Clinical Features)
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Transcript of 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
Ischemic Stroke Syndromes
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Ischemic Stroke Syndromes
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
Ischemic Stroke Syndromes
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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
Ischemic Stroke Syndromes
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Ischemic Stroke Syndromes
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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Ischemic Stroke Syndromes
Basilar Artery Occlusion
Severe quadriplegia
Coma
Locked-in syndrome-complete muscleparalysis except for upward gaze
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Ischemic Stroke Syndromes
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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