Stroke Syndromes

1. Stroke Syndromes Dr. Meg-angela Christi Amores

2. 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

3. 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

4. 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

5. 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

6. 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

7. Stroke within the Anterior Circulation

8. Middle Cerebral Artery

9. Middle Cerebral Artery • If occluded at its origin: • contralateralhemiplegia • Hemianesthesia • homonymous hemianopia • gaze preference to the ipsilateral side • If dominant hemisphere: global aphasia • If non-dominant hemisphere: anosognosia, constructional apraxia, and neglect

10. 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)

11. Middle Cerebral Artery

12. 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)

13. 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

14. Anterior Cerebral Artery

15. Anterior Cerebral Artery

16. 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

17. 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

18. Anterior Cerebral Artery

19. Anterior Cerebral Artery • Abulia (akineticmutism), slowness, delay, intermittent interruption, lack of spontaneity, whispering, reflex distraction to sights and sounds: Uncertain localization—probably cingulategyrus 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

20. Stroke within the Posterior Circulation • Posterior Cerebral Artery • result from atheroma formation or emboli that lodge at the top of the basilar artery

21. Posterior Cerebral Artery • P1 Syndromes • third nerve palsy with contralateral ataxia (Claude's syndrome) or with contralateralhemiplegia (Weber's syndrome) • contralateralhemiballismus (if subthalamic n) • thalamic Déjerine-Roussy syndrome - contralateralhemisensory loss followed later by an agonizing, searing or burning pain in the affected areas

22. Posterior Cerebral Artery • P2 Syndromes • infarction of the medial temporal and occipital lobes • Contralateral homonymous hemianopia with macula sparing • acute disturbance in memory (hippocampus) • peduncularhallucinosis - 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

23. 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

24. 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

25. 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

26. 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)

27. 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