YNDROMES Part II STROKE SYNDROMES Stroke Within the

YNDROMES. Part II

STROKE SYNDROMES

Stroke Within the Anterior Circulation – Middle 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 (M 1 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 (M 2 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 (A 1) • Connects the internal carotid artery to the anterior communicating artery – Postcommunal segment (A 2) *Pericallousal artery (A 3) • 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) P 1 syndrome: midbrain, subthalamic, and thalamic signs, which are due to disease of the proximal P 1 segment of the PCA or its penetrating branches • (2) P 2 syndrome: cortical temporal and occipital lobe signs, due to occlusion of the P 2 segment distal to the junction of the PCA with the posterior communicating artery.

Posterior Cerebral Artery • P 1 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 • P 2 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, and renal failure

• Carotid Doppler

• For the next meeting, read on Disturbances of Vision, Ocular Movement, and Hearing • Harrison’s Principles of Internal Medicine 17 th edition