Neuro - Anat & Phys (Intracranial hemorrhage & Strokes) Flashcards
Pg. 462-463 in First Aid 2014 Sections include: -Intracranial hemorrhage -Ischemic brain disease/stroke
Name 4 kinds of intracranial hemorrhage.
(1) Epidural hematoma (2) Subdural hematoma (3) Subarachnoid hematoma (4) Intraparenchymal (hypertensive) hemorrhage
What causes an epidural hematoma? To what is it often secondary?
Rupture of middle meningeal artery (branch of maxillary artery), often secondary to fracture of temporal bone
What clinical phenomenon is characteristic of epidural hematoma patients?
Lucid interval
What are 2 kinds of damage that can result from epidural hematoma? What is the pathogenesis leading to this damage?
Rapid expansion under systemic arterial pressure –> (1) transtentorial herniation, (2) CN III palsy
Describe the CT findings characteristic of an epidural hematoma. Of these, which is the most significant characteristic?
CT shows biconvex (lentiform), hyperdense (light) blood collection NOT CROSSING SUTURE LINES. CAN CROSS FALX, TENTORIUM.
What causes a subdural hematoma?
Rupture of bridging veins
What kind of bleeding occurs with a subdural hematoma? Explain the consequence of this.
Slow venous bleeding (less pressure = hematoma develops over time)
What are 4 patient populations in which subdural hematomas are seen? What are 3 predisposing factors to subdural hematomas?
Seen in (1) elderly individuals, (2) alcoholics, (3) blunt trauma, (4) shaken baby (Predisposing factors: brain atrophy, shaking, whiplash)
Describe the CT findings characteristic of a subdural hematoma. Of these, which is the most significant characteristic?
Crescent-shaped hemorrhage that CROSSES SUTURE LINES. Midline shift. CANNOT CROSS FALX, TENTORIUM.
What are 2 causes of a subarachnoid hemorrhage?
(1) Rupture of an aneurysm (such as berry [saccular] aneurysm, as seen in Marfan, Ehlers-Danlos, ADPKD) or (2) an AVM (Atriovenous malformation).
What is an example of aneursym that could rupture and lead to subarachnoid hemorrhage? What are 3 examples of conditions associated with such an aneurysm?
Rupture of an aneurysm (such as berry [saccular] aneurysm, as seen in Marfan, Ehlers-Danlos, ADPKD)
What are 2 significant findings in the history of present illness that may suggest subarachnoid hemorrhage?
(1) Rapid time course (2) Patients complain of “worst headache of my life (WHOML)”
What is the spinal tap finding associated with subarachnoid hemorrhage?
Bloody or yellow (xanthochromic) spinal tap
What are 2 risks following subarachnoid hemorrhage? How soon after? Which of these is visible on CT?
2-3 days afterward, risk of (1) vasospasm due to blood breakdown (not visible on CT, treat with nimodipine) and (2) rebleed (visible on CT)
How is vasospasm secondary to subarachnoid hemorrhage treated?
Nimodipine
What is another name for intraparenchymal hemorrhage? What most commonly causes it?
Intraparenchymal (hypertensive) hemorrhage; Most commonly caused by systemic hypertension
Other than systemic hypertension, what are 3 other conditions in which intraparenchymal (hypertensive) hemorrhage is seen?
Also seen with amyloid angiopathy, vasculitis, and neoplasm
Where in the brain and/or in what fashion does intraparenchymal (hypertensive) hemorrhage typically occur?
Typically occurs in basal ganglia and internal capsule (Charcot-Bouchard aneurysm of lenticulostriate vessels), but can be lobar
Name an aneurysm that affects internal capsule and is associated with intraparenchymal (hypertensive) hemorrhage.
Charcot-Bouchard aneurysm of lenticulostriate vessels
In the setting of ischemic brain disease or stroke, when does irreversible damage begin?
Irreversible damage begins after 5 minutes of hypoxia
What 4 parts of the brain are most vulnerable to ischemic brain disease or stroke (i.e., hypoxia)?
Most vulnerable - (1) hippocampus, (2) neocortex, (3) cerebellum, (4) watershed areas.
How are neurons impacted by ischemic brain disease or stroke?
Irreversible neuronal injury
How is MRI used for imaging stroke? What is the most significant use of MRI in the setting of stroke?
Bright on diffusion-weighted MRI in 3-30 minutes (highest sensitivity for early ischemia)
How is CT used for imaging stroke? What is the most significant use of CT in the setting of stroke?
Dark abnormality on noncontrast CT in ~12-24 hours. Absence of bright areas on noncontrast CT highly accurate to exclude hemorrhage (contraindication for tPA).
Give histologic features that characterize the following periods of time since an ischemic event: (1) 12-48 hrs (2) 24-72 hrs (3) 3-5 days (4) 1-2 weeks (5) > 2 weeks.
(1) Red neurons (2) Necrosis & Neutrophils (3) Macrophages (4) Reactive gliosis & Vascular proliferation (5) Glial scar
At what time period since an ischemic event can Red neurons be seen on histology?
12-48 hrs
At what time period since an ischemic event can Necrosis & Neutrophils be seen on histology?
24-72 hrs.
At what time period since an ischemic event can Macrophages be seen on histology?
3-5 days
At what time period since an ischemic event can Reactive gliosis & Vascular proliferation be seen on histology?
1-2 weeks
At what time period since an ischemic event can Glial scar be seen on histology?
> 2 weeks
What is hemorrhagic stroke? To what 3 conditions is it often due?
Intracerebral bleeding, often due to hypertension, anticoagulation, and cancer (abnormal vessels can bleed)
To what may hemorrhagic stroke be secondary, and why?
May be secondary to ischemic stroke followed by reperfusion (increased vessel fragility)
What is the most common site of intracerebral hemorrhage?
Basal ganglia are most common site of intracerebral hemorrhage
What is ischemic stroke, and what causes it? What results from ischemic stroke?
Acute blockage of vessels –> disruption of blood flow and subsequent ischemia; Results in liquefactive necrosis
What are the 3 types of Ischemic stroke?
(1) Thrombotic (2) Embolic (3) Hypoxic
What causes thrombotic ischemic stroke, and what is its usual context?
Due to a clot forming directly at the site of infarction (commonly the MCA) , usually over an atherosclerotic plaque
What is a common site of infarction for thrombotic ischemic stroke?
Commonly the MCA
What causes embolic ischemic stroke? What effect can it have?
An embolus from another part of the body obstructs a vessel. Can affect multiple vascular territories.
What is often an origin/type of embolic ischemic stroke that occurs?
Often cardioembolic
What causes hypoxic ischemic stroke?
Due to hypoperfusion or hypoxemia.
In what context is hypoxic ischemic stroke common? What does hypoxic ischemic stroke tend to affect?
Common during cardiovascular surgeries, tends to affect watershed areas
What is the treatment for ischemic stroke? What are the requirements for use of this treatment?
Treatment - tPA (if within 3-4.5 hr of onset and no hemorrhage/risk of hemorrhage)
What are 3 broad categories for reducing risk of ischemic stroke?
Reduce risk with (1) medical therapy (e.g., aspirin, clopidogrel); (2) Optimum control of blood pressure, blood sugars, and lipids; and (3) treat conditions that increase risk (e.g., atrial fibrillation)
What criteria/characteristics define Transient ischemic attack? What causes the deficits in this case?
Brief, reversible episode of focal neurologic dysfunction without acute infarction (negative MRI), with majority resolving in < 15 minutes (Note: TIA diagnosis is now tissue based); Deficits due to focal ischemia
What are 2 examples of medical therapy that may reduce risk of ischemic stroke?
(1) Aspirin (2) Clopidogrel
What is an example of an underlying condition that may be treated in order to reduce risk of ischemic stroke?
Atrial fibrillation
What are 3 clinical values to get under optimum control in order to reduce risk of ischemic stroke?
(1) Blood pressure (2) Blood sugars (3) Lipids
