Snapshot A 55-year-old man presents to the emergency department for difficulty with speech and weakness in the right upper extremity. He was last known to be neurologically normal 2 hours prior to presentation. He has a medical history of atrial fibrillation, hypertension, hyperlipidemia, and type 2 diabetes mellitus. He smokes approximately 1 pack of cigarettes daily for the past 15 years. Physical examination is notable for 2/5 power in the right upper extremity and word finding difficulty. A non-contrast head CT is performed, which does not demonstrate an intracranial hemorrhage. He is immediately started on alteplase. Introduction Definition login to view 3 more bullets Epidemiology login to view 16 more bullets Pathogenesis login to view 13 more bullets Large vs. Small Vessel Infarcts Type Comments Large vessel Occlusion of the major blood vessels such as the middle cerebral artery Occlusion is most often caused byemboli Small vessel Occlusion of the small penetrating arteries that supply the deep cerebral structures such as basal ganglia thalamus internal capsule Sometimes called lacunar infarcts Presentation Ischemic Stroke Syndromes Anterior Circulation Stroke Findings Middle cerebral artery (MCA) stroke Symptoms contralateral weakness and sensory loss in the face and upper limb hemineglect if the non-dominant hemisphere is involved aphasia Broca's aphasia if the superior division of the MCA is involved in the dominant hemisphere Wernicke's aphasia if the inferior division of the MCA is involved in the dominant hemisphere may also result in a right superior quadrant visual field defect Lesion localization motor and sensory cortices distributed by the MCA Wernicke's or Broca's area Anterior cerebral artery (ACA) stroke Symptoms contralateral weakness and sensory loss in the lower extremity Lesion localization motor and sensory cortices supplied by the: ACA Lenticulostriate artery stroke Symptoms pure, unilateral motor weakness face and body in the absence of cortical signs (e.g., neglect) pronator drift pure, unilateral sensory weakness ataxic hemiparesis dysarthria-clumsy hand syndrome proprioception remains intact (e.g., normal Romberg test). Comments branch arteries originating directly from larger arteries a common site of lacunar infarcts secondary to chronic hypertension Ischemic Stroke Syndromes Posterior Circulation Stroke Findings Medial medullary (Dejerine) syndrome Secondary to occlusion of the paramedian branches of the anterior spinal artery and/or vertebral artery Symptoms triad ipsilateral hypoglossal palsy contralateral hemiparesis contralateral lemniscal sensory loss (e.g., proprioception) Lesion localization lateral corticospinal tract caudal medulla medial lemniscus Lateral medullary (Wallenberg) syndrome Secondary to occlusion of the posterior inferior cerebellar artery (PICA) or vertebral artery Symptoms dysphagia hoarseness ↓ gag reflex vertigo ↓ pain and temperature sensation of the: ipsilateral face contralateral body Horner's syndrome ataxia Lesion localization lateral medulla involving the: nucleus ambiguus vestibular nuclei lateral spinothalamic tract spinal trigeminal nucleus sympathetic fibers inferior cerebellar peduncle Lateral pontine syndrome Secondary to anterior inferior cerebellar artery Symptoms facial paralysis ↓ salivation, lacrimation, and taste from the anterior tongue (2/3rd) vertigo ↓ pain and temperature sensation of the: ipsilateral face contralateral body ipsilateral Horner's ataxia Lesion localization Lateral pons involving the: facial nucleus vestibular nuclei spinothalamic tract spinal trigeminal nucleus sympathetic fibers middle and inferior cerebellar peduncle Locked-in syndrome Secondary to occlusion of the basilar artery Symptoms quadraplegia bulbar manifestations able to perform vertical eye movements preserved conciousness Lesion localization ventral pons, lower midbrain, and medulla affecting the: corticospinal and corticobulbar tracts oculomotor nerve nuclei paramedian pontine reticular formation Posterior cerebral artery (PCA) occlusion Symptoms contralateral hemianopsia with macular sparing Lesion localization occipital lobe Paramedian midbrain (Benedikt) syndrome Symptoms Ipsilateral CN III palsy, contralateral hemiataxia, tremor/choreoathesois, hemiparesis Lesion localization Paramedian midbrain affecting the midbrain tegmentum, red nucleus, superior cerebellar penducle, and corticospinal tract Imaging Computerized tomography (CT) login to view 3 more bullets Magnetic resonance imaging (MRI) login to view 2 more bullets Echocardiography login to view 2 more bullets Studies Labs login to view 7 more bullets Histology History login to view 16 more bullets Histology Time after Ischemic Event Histologic findings 12-24 hours Red neuron cytoplasm is eosinophilic nuclei are pyknotic cell body shrinkage loss of Nissl substance 1-3 days Tissue necrosis Neutrophilic infiltration 3-5 days Tissue necrosis Neutrophilic infiltration 1-2 weeks Reactive gliosis Vascular proliferation > 2 weeks Glial scar Differential Hemorrhagic stroke login to view 2 more bullets Transient ischemic attack login to view 2 more bullets Posterior reversible encephalopathy syndrome (PRES) login to view 3 more bullets Treatment Medical login to view 30 more bullets Operative login to view 4 more bullets Complications Intracerebral hemorrhage Seizures Aspiration pneumonia Central post-stroke pain