Pathology Vascular Abnormalities

Question 1

At what blood pressure does widespread ischemic-hypoxic injury occur?

Answer 1

Systolic pressures under 50 mmHg

Question 2

What neurons are most susceptible to hypoxic injury

Answer 2

Pyramidal cells of the hippocampus/neocortex

Purkinjie cells of the cerebellum

Question 3

What type of necrosis does brain tissue go through?

Answer 3

Liquefactive

Question 4

Early changes in brain necrosis

Answer 4

Occurs 12-24 hrs after injury

• generates red neurons from acute neuronal changes
• also sees increased neutrophil influx and resulting inflammation

Question 5

Subacute changes of necrosis

Answer 5

Occurs at 24hrs- 2 weeks

• actual necrosis of brain tissue
• influx of macrophages
• vascular proliferation
• reactive gliosis (astrocytes are the most common to undergo changes)

Question 6

Where do most emboli seen in embolic brain infractions come from?

Answer 6

Cardiac system (atrial fibrillation)

Question 7

What is a paradoxical embolism?

Answer 7

An emboli that starts in the venous system, and then crosses over into the arterial circulation via a patent foramen ovale or ASD
- ends up in th brain

Question 8

What specific region of the brain is most affected by embolic infarction?

Answer 8

Middle cerebral artery area

also can be found in carotid bifurcation or the ends of the basilar artery

Question 9

What usually causes lacunae infarcts?

Answer 9

Arteriolar sclerosis usually a result of a long-standing HTN that is not treated.

Lacunae infarcts = multiple small emboli cause infractions

Question 10

What does gliosis mean?

Answer 10

Repair and scaring of the brain

- done predominantly by astrocytes

Question 11

Thrombosis vs emboli

Answer 11

Thrombosis
- clot forms directly at the location

Emboli
- clot travels, (or part of a clot, fat,air, etc.) to another location and binds there

Question 12

Spontaneous intraparenchymal hemorrhages

Answer 12

Small intraparenchymal vessels rupture spontaneously within the brain tissue itself

Common risk factors

• 60 yrs and older
• long standing HTN (leading cause)

Can be clinically devastating or silent, so symptoms vary dramatically

Location of occurrence is highest at:

• basal ganglia
• thalamus
• pons
• cerebellum

Question 13

Cerebral amyloid Angiopathy (CAA)

Answer 13

Some amyloid peptides deposit into walls of small-medium meningeal/cortical vessels
- stain Congo red and look like small rigid pipes under the microscope

Most often occur in specifics lobes of the cerebrum
- specific symptoms based on which lobe is affected

Question 14

What is the most frequent cause of clinically significant non traumatic subarachnoid hemorrhage?

Answer 14

Saccular (berry) aneurysm

“Sudden excruciating headache that hits peak pan quickly and doesnt go away”
- usually occurs in acute increases of intracranial pressures (i.e valsalva maneuver)

Question 15

Where are most saccular aneurysms found?

Answer 15

In the anterior circulation near the arterial branch (connecting) points

• in 20-30% of cases, multiple occur at once
• anterior communicating/ anterior cerebral artery connection point is the highest rate

Question 16

How to aneurysms form

Answer 16

Due to underlying defects in the vessel media
- NOT present at birth

Examples of causes:

• polycystic kidney disease
• Ehler-Danlos syndrome

Question 17

Types of vascular malformations of the brain

Answer 17

Arteriovenous malformations (AVM)

• is the most common and dangerous
• is most common in males between 10-30 yrs
• seizures, intracranial hemorrhages and subarachnoid hemorrhages lead to these

Cavernous malformations

Capillary telangiectasias
- can show multiple AVMs

Venous angiomas