Stroke Syndromes

Dr. Meg-angela Christi Amores

Stroke

• Cerebrovascular disease • ischemic stroke, hemorrhagic stroke, and

cerebrovascular anomalies such as intracranial aneurysms and arteriovenous malformations (AVMs)

• Stroke• abrupt onset of a neurologic deficit that is attributable

to a focal vascular cause• Ischemic or hemorrhagic

Stroke

• Ischemic Stroke• Acute occlusion of an intracranial vessel causes

reduction in blood flow to the brain region it supplies• A fall in cerebral blood flow to zero causes death of

brain tissue within 4–10 min• values <16–18 mL/100 g tissue per min cause infarction

within an hour• values <20 mL/100 g tissue per min cause ischemia

without infarction unless prolonged for several hours or days

Ischemic stroke

• Ischemic penumbra• Tissue surrounding the core region of infarction that is

ischemic but reversibly dysfunctional • will eventually infarct if no change in flow occurs

• Fever dramatically worsens ischemia, as does hyperglycemia[glucose > 11.1 mmol/L (200 mg/dL)], so it is reasonable to suppress fever and prevent hyperglycemia as much as possible

Ischemic Stroke

• Pathophysiology• 1) occlusion of an intracranial

vessel by an embolus that arises at a distant site

• (2) in situ thrombosis of an intracranial vessel, typically affecting the small penetrating arteries that arise from the major intracranial arteries

• (3) hypoperfusion caused by flow-limiting stenosis of a major extracranial

Stroke Syndromes

• Patient presentation can localized area of the brain affected/ blood vessel occluded

• Divided into:– (1) large-vessel stroke within the anterior

circulation– (2) large-vessel stroke within the posterior

circulation– (3) small-vessel disease of either vascular bed

Stroke within the Anterior Circulation

Middle Cerebral Artery

Middle Cerebral Artery

• If occluded at its origin:– contralateral hemiplegia– Hemianesthesia– homonymous hemianopia– gaze preference to the ipsilateral side– If dominant hemisphere: global aphasia– If non-dominant hemisphere: anosognosia,

constructional apraxia, and neglect

Middle Cerebral Artery

• Somatic motor area for face and arm and the fibers descending from the leg area to enter the corona radiata and corresponding somatic sensory system

• Paralysis of the contralateral face, arm, and leg; • sensory impairment over the same area (pinprick,

cotton touch, vibration, position, two-point discrimination, stereognosis, tactile localization, barognosis, cutaneographia)

Middle Cerebral Artery

Middle Cerebral Artery

• Motor aphasia: Motor speech area of the dominant hemisphere

• Central aphasia, word deafness, anomia, jargon speech, sensory agraphia, acalculia, alexia, finger agnosia, right-left confusion (the last four comprise the Gerstmann syndrome): Central, suprasylvian speech area and parietooccipital cortex of the dominant hemisphere

• Conduction aphasia: Central speech area (parietal operculum)

Middle Cerebral Artery

• Homonymous hemianopia (often homonymous inferior quadrantanopia): Optic radiation deep to second temporal convolution

• Paralysis of conjugate gaze to the opposite side: Frontal contraversive eye field or projecting fibers

Anterior Cerebral Artery

Anterior Cerebral Artery

Anterior Cerebral Artery

• 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– result from atheroma formation or emboli that

lodge at the top of the basilar 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 n)• 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• infarction of the medial temporal and occipital lobes• Contralateral homonymous hemianopia with macula

sparing• acute disturbance in memory (hippocampus)• peduncular hallucinosis - visual hallucinations of

brightly colored scenes and objects• infarction in the distal PCAs produces cortical blindness • Anton's syndrome – unaware of blindness and in denial

Basilar Artery

• 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

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

Primary and Secondary Prevention

• General Principles• medical and surgical interventions• lifestyle modifications• Evaluation of a patient's clinical risk profile

• Atherosclerosis risk factors• Older age, family history of thrombotic stroke, diabetes

mellitus, hypertension, tobacco smoking, abnormal blood cholesterol [particularly, low high-density lipoprotein (HDL) and/or high low-density lipoprotein (LDL)

Primary and Secondary Prevention

• Antiplatelet Agents• inhibiting the formation of intraarterial platelet

aggregates• Aspirin, clopidogrel, and the combination of aspirin plus

extended-release dipyridamole • Aspirin dose: 50–325 mg/d

• Anticoagulation• For AF patients: Warfarin