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Updated: Oct 12 2024

Stroke

  • 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
      • a sudden loss of blood supply to an area of the brain leading to
        • a neurologic deficit
          • the deficit depends on which area of the brain is affected
    • Epidemiology
      • incidence
        • 3rd leading cause of death in the United States
      • risk factors
        • hypertension
        • diabetes
        • smoking
        • atrial fibrillation
        • mechanical valves
        • valvular abnormalities
        • patent foramen ovale
        • significantly decreased ejection fraction
        • hypercoagulable state
        • family history
        • prior history of
          • stroke
          • vascular disease
    • Pathogenesis
      • ↓ blood supply to a region of the brain for enough time to result in infarcted (liquefactive necrosis) cerebral tissue
        • the most vulnerable to ischemic hypoxia is the hippocampus
        • after 5 minutes, irreversible neuronal damage occurs
        • causes of this ↓ blood supply include
          • embolic infarction
            • a clot (typically) from one region of the body travels in the blood stream and occludes a vessel supplying the brain
            • consider in cases of sudden neurologic deficit
              • maximal neurologic deficit occurs at the onset
            • large vessel infarcts are commonly due to an embolism
          • thrombotic infarction
            • a clot is locally formed in the wall of the blood vessel usually
              • where an atherosclerotic plaque is found
            • typically has a stuttering course
      • 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)
      • indications
        • a non-contrast head CT should be performed in patients presenting with symptoms concerning for stroke and to exclude intracerebral hemorrhage
        • CT angiography should be performed to assess for a thrombus and to evaluate the carotid and vertebral neck arteries
    • Magnetic resonance imaging (MRI)
      • indications
        • MRI/MRA can aid in assessing infarct volume for further management
    • Echocardiography
      • indications
        • evaluates evidence of an intracardiac shunt or ventricular thrombus
  • Studies
    • Labs
      • fingerstick blood glucose
        • should be performed immediately in all suspected stroke patients
      • complete blood count
      • basal metabolic panel
      • prothrombin time
      • partial thromboplastin time
      • cardiac enzymes
    • Histology
    • History
      • the NIH stroke scale stratifies these patients
        • level of consciousness
        • ask month and age
        • follows commands (blink eye and squeeze hands)
        • horizontal eye movements
        • visual fields
        • facial palsy
        • left arm motor drift
        • right arm motor drift
        • left leg motor drift
        • right leg motor drift
        • limb ataxia
        • sensation
        • language/aphasia
        • dysarthria
        • extinction/inattention
      • 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
      • differentiating factor
        • hyperdense lesion in a non-contrast head CT
    • Transient ischemic attack
      • differentiating factor
        • normal MRI brain
    • Posterior reversible encephalopathy syndrome (PRES)
      • differentiating factor
        • hypertension that can lead to confusion, visual changes, and seizures
        • MRI demonstrating cerebral edema in the posterior hemispheres
  • Treatment
    • Medical
      • intravenous tPA
        • indication
          • used in patients presenting with
            • stroke symptoms, excluded to have an intracranial hemorrhage, and time since symptom onset is within the last 3-4.5 hours
        • contraindications
          • history of stroke/head trauma in the past 3 months
          • history of intracranial hemorrhage
          • major surgery in the past 14 days
          • GI or urinary tract bleeding in the past 21 days
          • myocardial infarction in the previous 3 months
          • arterial puncture at a non-compressible site in past 7 days
          • resolving stroke symptoms
          • very minor and isolated neurological symptoms
          • seizure at the onset of stroke
          • persistent hypertension SBP > 185 mmHg or DBP > 110 mmHg
          • use of direct thrombin inhibitors (such as dabigatran or argatroban)
          • use of factor Xa inhibitors (such as rivaroxaban or apixaban)
          • active bleeding or acute trauma with fractures
          • platelets < 100,000, serum glucose < 50 mg/dL or > 400 mg/dL
          • INR > 1.7 or PT > 15 seconds if on warfarin
          • elevated PTT if on heparin
          • head CT showing hemorrhage or multilobular infarction > 33% of a cerebral hemisphere
          • intracranial neoplasm, arteriovenous malformation, or aneurysm
      • non-tPA candidate
        • medical management
          • aspirin
          • statin
          • clopidogrel
          • blood pressure control
            • most important management for hypertensive strokes and vascular dementia
    • Operative
      • mechanical thrombectomy
        • indication
          • in proximal large artery occlusion involving the anterior circulation
            • whether or not the patient received tPA
  • Complications
    • Intracerebral hemorrhage
    • Seizures
    • Aspiration pneumonia
    • Central post-stroke pain
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