questions 10

Ischemic Brain Disease

Topic updated on 04/24/17 11:29am

  • A 60-year-old woman presents with acute onset of right arm and leg weakness, with normal sensation and speech. Her initial CT is normal.
    (Small lacunar infarct of the left internal capsule) 

  • A 44-year-old man presents with an acute onset of dysarthria, Horner syndrome affecting the right side, hicups, right ataxia, sensory loss to the pinprick over the right side of the face and the left side of the body, and intact cognition.
    (Posteroinferior cerebellar artery infarct in the distribution of the lateral medulla)
  • Acute onset of focal neurologic deficits resulting from
    • diminished blood flow (ischemic stroke)
    • hemorrhage (hemorrhagic stroke)
    • irreversible damage after 5 minutes
  • Most vulnerable brain regions
    • hippocampus, neocortex, cerebellum, and watershed areas 
  • Risk factors
    • diabetes
    • smoking
    • atrial fibrillation 
    • cocaine
  • Etiology
    • 35% - atherosclerosis of the extracranial vessels (carotid atheroma)
    • 30% - cardiac and fat emboli, endocarditis
    • 15% - lacunar
    • 10% - parenchymal hemorrhage
    • 10% - subarachnoid hemorrhage
  • Transient ischemic attack (TIA)
    • charcaterized by transient neurologic deficits for less than 24 hours (usually less than 1 hr.)
  • Types of stroke
    • thrombotic/atherosclerotic infarct
      • most common type of stroke
      • anemic/pale (liquifactive necrosis)
        • not reperfused
        • forms cystic cavity with reactive gliosis
      • usually at periphery of cortex supplied by MCA
    • embolic infarcts
      • hemorrhagic/red infarct
        • due to repurfusion once embolus is degraded
      • commonly from left heart (atrial fibrilation) or atherosclerotic plaques
      • middle cerebral artery at greatest risk
    • lacunar infarcts 
      • occur in areas supplied by small perforating vessels
        • mainly basal ganglia
        • caused by hyaline arteriolosclerosis
      • risk factors 
        • atherosclerosis
        • hypertension
        • diabetes
    • hemorrhagic stroke
      • intracerebral bleeding often due to aneurysm rupture
        • see Aneurysms
      • may be secondary to ischemic stroke following reperfusion
    • watershed infarcts
      • occurs at areas at border of two arterial supplies
      • often follow prolonged hypotension
      • damage is usually bilateral, deep cortical areas
Monocular Blindness
MCA Aphasia, neglect, hemiparesis, gaze preference, and homonymous hemianopsia 
ACA Leg paresis, hemiplegia, and urinary incontinence
PCA Homonynmous hemianopsia
Basilar Artery Coma, cranial nerve palsies, apnea, drop attack, and vertigo 
Lacunar stroke

Pure motor (internal capsule affected) or sensory stroke (thalamus affected), dysarthria, and ataxic hemiparesis

  • Imaging
    • CT without contrast for acute presentation
      • important to diagnose as ischemic or hemorrhagic
      • bright on diffusion weighted MRI in 3-30 minutes and remains bright for 10 days
      • dark on CT in 24 hours
    • MRI for subacute
    • vascular studies of intra and extracranial vessels
  • Histology
    • red neurons (12-28 hours)
    • necrosis + neutrophils (24-72 hours)
    • macrophages (2-3 days)  
    • reactive gliosis + vascular proliferation (1-2 weeks)
    • glial scar (> 2 weeks) 
  • For occlusive disease give tPA if within 3 hrs
  • For embolic disease and hypercoagulable states give warfarin/aspirin once the hemorrhagic stroke has been ruled out
  • Mechanical hyperventilation may be used to lower intracranial pressure acutely as hypocapnia causes cerebral vasoconstriction and decreased blood flow 


Qbank (4 Questions)

(M1.NE.33) A patient is transferred from an outside hospital by family request. The patient is a 76-year-old gentleman who developed acute onset left-sided weakness four days ago with the imaging findings seen in Figure A. Despite aggressive care, the patient dies shortly after transfer. The family requests an autopsy. What histological finding would you expect to find on evaluation of the patient's brain? Topic Review Topic
FIGURES: A          

1. Red neurons
2. Neutrophilic infiltration and necrosis
3. Macrophage infiltration and phagocytosis
4. Reactive gliosis and vascular proliferation
5. Glial scarring

(M1.NE.38) A 58-year-old man with history of diabetes and hypertension suffers a cardiac arrest at home. The family calls 911, yet no one performs CPR. Five minutes after the arrest, EMS arrives to begin resuscitation. At this point, which region of the CNS is most likely to suffer ischemic damage? Topic Review Topic

1. Thalamus
2. Spinal cord
3. Pons
4. Medulla
5. Hippocampus

(M1.NE.4671) A 74-year-old African-American woman is brought to the emergency department by her home health aid. The patient was eating breakfast this morning when she suddenly was unable to lift her spoon with her right hand. She attempted to get up from the table, but her right leg felt weak. One hour later in the emergency department, her strength is 0/5 in the right upper and right lower extremities. Strength is normal in her left upper and lower extremities. Sensation is normal bilaterally. An emergency CT of the head does not show signs of hemorrhage. Subsequent brain MRI shows an infarct involving the internal capsule. Which of the following is true about her disease process?
Topic Review Topic

1. The most important risk factors are hypertension and diabetes
2. The most common cause is embolism originating from the left atrium
3. It is caused by ischemia to watershed areas
4. IV thrombolysis cannot be used
5. The most important risk factors are ethnicity and sex

(M1.NE.4671) A 75-year-old woman with a history of stroke 1 year ago was found unconscious on the floor of her home by her son. The patient was brought to the emergency department by ambulance but expired prior to arrival. An autopsy was performed and showed the cause of death to be a massive ischemic stroke. The coroner also examined sections taken from the area of her prior stroke. Which histologic finding would be prominent in the area of her stroke from one year prior? Topic Review Topic

1. Red neurons
2. Necrosis and neutrophils
3. Macrophages
4. Reactive gliosis and vascular proliferation
5. Cyst formed by astrocyte processes

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