Transcript Stroke Syndromes2

YNDROMES .
STROKE SYNDROMES
Stroke Within the Anterior Circulation
– Middle Cerebral Artery
– Anterior Cerebral Artery
– Anterior Choroidal Arteries
– Internal Carotid Artery
– Common Carotid Artery
Middle Cerebral Artery
• Occlusion of the proximal MCA or
one of its major branches is most
often due to an embolus rather
than intracranial atherothrombosis
• The cortical branches of the MCA
supply the lateral surface of the
hemisphere
Middle Cerebral Artery
• The proximal MCA (M1 segment) supplies the
following:
–
–
–
–
–
Putamen
Outer globus pallidus
Posterior limb of the internal capsule
Corona radiata
Most of the caudate nucleus
• In the sylvian fissure, the MCA divides into the superior
and inferior divisions (M2 branches)
– Inferior division supplies
• Inferior parietal and temporal cortex
– Superior division supplies
• Frontal and superior parietal cortex
Middle Cerebral Artery
• entire MCA is occluded at its origin :
– contralateral hemiplegia,
hemianesthesia, homonymous
hemianopia, and a day or two of gaze
preference to the ipsilateral side
– Dysarthria is common because of
facial weakness
– global aphasia
– anosognosia, constructional apraxia,
and neglect
• Middle Cerebral Artery: Partial Syndromes
– Brachial syndrome : embolic occlusion of a single
branch include hand, or arm and hand, weakness
alone
– Frontal Opercular Syndrome: facial weakness with
nonfluent (Broca) aphasia, with or without arm
weakness
– Lacunar stroke within internal capsule - pure
motor stroke or sensory-motor stroke
contralateral to the lesion
Middle Cerebral Artery
Stroke within the Anterior Circulation
• Anterior Cerebral Artery
Anterior Cerebral Artery
• Divided into 2 segments:
– Precommunal Circle of Willis (A1)
• Connects the internal carotid artery to the anterior
communicating artery
– Postcommunal segment (A2)
*Pericallousal artery (A3)
• Main terminal branches of the ACA
Anterior Cerebral Artery
• Supplies the anterior limb of the internal
capsule, the anterior perforate substance,
amygdala, anterior hypothalamus, and the
inferior part of the head of the caudate
nucleus
• Occlusion of the proximal ACA is usually well
tolerated because of collateral flow through
the anterior communicating artery and
collaterals through the MCA and PCA
Anterior Cerebral Artery
• Paralysis of opposite foot and leg:
Motor leg area
• A lesser degree of paresis of
opposite arm: Arm area of cortex or
fibers descending to corona radiata
• Cortical sensory loss over toes, foot,
and leg: Sensory area for foot and
leg
• Urinary incontinence: Sensorimotor
area in paracentral lobule
Anterior Cerebral Artery
Anterior Cerebral Artery
• Abulia (akinetic mutism), slowness, delay,
intermittent interruption, lack of spontaneity,
whispering, reflex distraction to sights and
sounds: Uncertain localization—probably
cingulate gyrus and medial inferior portion of
frontal, parietal, and temporal lobes
• Impairment of gait and stance (gait apraxia):
Frontal cortex near leg motor area
• Dyspraxia of left limbs, tactile aphasia in left
limbs: Corpus callosum
Stroke within the Posterior Circulation
– Posterior Cerebral Artery
– Vertebral Artery
– Posterior Inferior Cerebellar Artery
– Basilar Artery
Stroke within the Posterior Circulation
• Posterior Cerebral Artery
– result from atheroma formation or emboli that
lodge at the top of the basilar artery
– May also be caused by dissection of the vertebral
artery or fibromuscular dysplasia
Posterior Cerebral Artery
• (1) P1 syndrome: midbrain, subthalamic, and
thalamic signs, which are due to disease of the
proximal P1 segment of the PCA or its
penetrating branches
• (2) P2 syndrome: cortical temporal and
occipital lobe signs, due to occlusion of the P2
segment distal to the junction of the PCA with
the posterior communicating artery.
Posterior Cerebral Artery
• P1 Syndromes
• third nerve palsy with contralateral ataxia (Claude's
syndrome) or with contralateral hemiplegia (Weber's
syndrome)
• contralateral hemiballismus (if subthalamic nucleus is
involved)
• thalamic Déjerine-Roussy syndrome - contralateral
hemisensory loss followed later by an agonizing,
searing or burning pain in the affected areas
Posterior Cerebral Artery
• P2 Syndromes
• Occulsion of the PCA causes infarction of the medial
temporal and occipital lobes
• Contralateral homonymous hemianopia with macula
sparing is the usual manifestation
• acute disturbance in memory (hippocampus)
• peduncular hallucinosis - visual hallucinations of
brightly colored scenes and objects
• infarction in the distal PCAs produces cortical blindness
(blindness with preserved PLR)
• Anton's syndrome – unaware of blindness and in denial
Basilar Artery
• Atheromatous lesions are most frequent in the
proximal basilar and the distal vertebral segments
• Complete basilar occlusion :
• a constellation of bilateral long tract signs (sensory and
motor) with signs of cranial nerve and cerebellar dysfunction
• “locked-in" state of preserved consciousness with
quadriplegia and cranial nerve signs suggests
complete pontine and lower midbrain infarction
Basilar Artery
• TIAs in the proximal basilar distribution may produce
vertigo
• Occlusion of the superior cerebellar artery results in
– Ipsilateral cerebellar ataxia, nausea and vomiting,
dysarthria, contralateral loss of pain and temp sensation
• Occusion of the anterior inferior cerebellar artery
results in
– Ipsilateral deafness, facial weakness, vertigo, nausea and
vomiting, nystagmus, tinnitus and contralateral loss of pain
and temperature sensation
Imaging
• CT Scan
• identify or exclude hemorrhage as the cause of stroke
• the infarct may not be seen reliably for 24–48 h
• may fail to show small ischemic strokes in the posterior
fossa
• MRI
• reliably documents the extent and location of infarction
in all areas of the brain
• less sensitive than CT for detecting acute blood
Imaging
• Cerebral Angiography
• "gold standard" for identifying and quantifying
atherosclerotic stenoses of the cerebral arteries
• used to deploy stents within delicate intracranial vessels
• intraarterial delivery of thrombolytic agents
• Carries the risk for arterial damage, groin hemorrhage,
embolic stroke, embolic stroke, and renal failure
• Carotid Doppler
• For the next meeting, read on Disturbances of
Vision, Ocular Movement, and Hearing
• Harrison’s Principles of Internal Medicine 17th
edition