Download Cerebrovascular Diseases

Cerebrovascular Diseases
Learning Objectives:
1) Define stroke, ischemia, hypoxia, and anoxia
a. Stroke (apoplexy) –
i. A transient ischemic attack (TIA) is a temporary (<24hrs) deficit due to
temporarily decreased perfusion
ii. Caused by
1. Brain infarction 80%
2. Intracerebral hemorrhage 10%
3. Subarachnoid hemorrhage 7%
4. Misc 3%
iii. Stroke is the 3rd leading cause of death in the elderly and the most
prevalent neurological disorder
b. Ischemia – decrease or lack of blood
c. Hypoxia – decrease or lack of oxygen
d. Anoxia – no oxygen
2) List the different causes of stroke and discuss their relative prevalence, their gross and
histological features, and their pathophysiology
Causes of Stroke
Prevalence
Gross features
Pathophysiology
Brain Infarction
1) Thrombic
2) Embolic
80%
Acute (week 1)–
softening, blurred
grey-white margin,
swelling with
midline shifts
Subacute
(weeks2&3) – tissue
disintegrates, sharp
demarcation of
infracted area
Chronic (weeks 4+) –
cavitation, Gliosis
(firm tissue)
Thrombotic – caused by
atherosclerosis
Embolic – caused by mural
thrombi, valvular vegetations,
fat emboli
Patterns of injury:
1) Focal infarction
a. Outcome is focal deficit
(classic stroke)
2) Focal patterns resulting
from intermediate degrees
of global ischemia
a. Hippocampal and
cerebellar injury
b. Laminar necrosis
c. Watershed infarction
3) Global (entire brain)
infarction
a. Ischemic/hypoxic
encephalopathy (TIA or
brain death)
1) From hypertension
a. Basal ganglia (common
Thrombosis @
carotid bifurcation is
the most common
Embolism – most
often from the heart
Intracerebral
hemorrhage
10%
Bleeding into the
basal ganglia, pons,
-
Due to
hypertension
and cerebellum
Subarachnoid
hemorrhage
- Due to
ruptured berry
aneurysm
7%
Miscellaneous
3%
Massive, clinically
significant
subarachnoid
hemorrhage is
almost always due
to rupture of a berry
aneurysm **
for hypertensive
hemorrhages)
b. Pontine and cerebellar
2) From berry aneurysms
a. Massive subarachnoid
hemorrhage
3) From vascular
malformations
a. Arteriovenous
malformation
b. Cavernous angioma
c. Venous malformation
Focal subarachnoid
hemorrhage is common
overlying contusions, infarcts,
infectious foci
Berry (secular) aneurysm –
involves Circle of Willis, found
in 2% of adults, etiology
unknown
1) Aneurysm wall consists of
vascular intima and
adventitia, with absent
smooth muscle and elastic
2) Warning symptoms due to
leakage or nerve
compression (worst
headache ever, vomiting,
loss of consciousness)
3) Sudden death (25-50%)
4) Acute vasospasm leading to
infarctions (and focal
deficits)
5) Rebleeding occurs in
survivors
3) Describe the different types of vascular malformation in the CNS. Differentiate them
according to types of component vessels and clinical signs and symptoms
Component
vessels
Clinical signs
Arteriovenous
malformation
Cavernous
Angioma
Venous
Angioma
Capillary
telangiectasis
Arteries and veins
Veins
Veins
Capillaries
Arterial pressure
Abnormal,
Abnormal,
Dilated, but
blood shunted into
venous system 
veins dilate and
sclerose in
response
Symptoms
Notes
Abnormal veins
prone to leakage,
causing seizures
and massive
hemorrhages
Lesions are
congenital, but: can
be silent for many
years, symptoms
typically occur in
young adults
dilated and
hyalinized veins
arranged
compactly with
no intervening
brain tissue
Can cause
hemorrhage
dilated veins
dispersed in
brain tissue
otherwise normal
capillaries
dispersed in
normal brain
tissue
DO NOT cause
hemorrhage
Virtually never
causes symptoms
NO intervening
neural
parenchyma
Throughout
intervening
brain tissue, do
not generally
bleed
Usually an
incidental finding
on autopsy
4) Describe the pathophysiological, histological, and clinical consequences of hypertension
on the brain
a. Acute hypertension – medical emergency
i. Vessels begin to die, leakage, hemorrhage
1. Pink necrosis called fibrinoid necrosis of the vessel walls
ii. Diffuse cerebral dysfunction
b. Chronic hypertension – more common
i. Cause slower changes that occur over years
ii. Atherosclerosis occurs
iii. Arteriolar changes
1. Arteriolar sclerosis
2. Pulsating of vessels
3. Microscopic hemorrhages lead to tiny cavities (lacunes)
4. Microscopic aneurysms (Charcot-Bouchard) can lead to larger
hemorrhages
5) Compare and contrast Binswanger disease and Leucoairosis
a. Binswanger disease
i. White matter infarcts*
ii. Destruction of white matter
iii. Clinical deficits
iv. Rare
b. Leucoairosis
i. Periventricular signal changes on CT, MRI
ii. Pathlogical significance unkown
iii. Clinical significance unknown
iv. Common in the elderly**
v. NOT INFARCTION