00:01
Now let's talk about the 4th type of hemorrhage.
intraparenchymal
hemorrhage which is also a type of hemorrhagic stroke in
addition to an intracranial
hemorrhage type. Intraparenchymal hemorrhages are
hemorrhages as a result of
intracerebral bleeding, bleeding within the brain parenchyma
or brain tissue and we can
see 2 basic types of intraparenchymal hemorrhage, lobar
hemorrhages out in the lobes
of the brain and deep subcortical hemorrhages which we see
with hypertension.
00:31
When we think about intraparenchymal hemorrhages, these
commonly arise from
deep penetrating cerebral blood vessels and arteries either
in the deep subcortical
areas or out in the lobes of the brain. The deeper arteries,
the deep subcortical
hemorrhages, these arteries can be affected by
lipohyalinosis, microaneurysm formation,
or arteriosclerosis as a result of longstanding
hypertension. Arteriosclerosis results
from increase in the smooth muscle within and around the
blood vessels as a result of
longstanding hypertension and that increase in smooth muscle
can result in damage to the
blood vessels and ultimately hemorrhage. We can see 2 types
of intraparenchymal
hemorrhage, lobar and deep subcortical hemorrhages and here
you see 2 examples on
non-contrast head CT. On the left, we can see a lobar
hemorrhage. This is an area of
hyperdense signal out in the lobe, the frontal lobe of the
brain and we see different
causes for lobar hemorrhages than the deep subcortical
hemorrhages which we see on
the right. This is a deeper focus, again, of hyperdense
signal consistent with hemorrhage
which we commonly see the deep subcortical hemorrhages with
hypertensive hemorrhage.
01:49
Let's talk about the types of intraparenchymal hemorrhages
in our diagnostic investigation
and why they occur. These hemorrhages occur from blood that
is extravasating from
ruptured arteries or vessels which results in a neurologic
deficit. Patients typically present
with a focal neurologic deficit, a stroke-like symptom, with
or without headache and
headache is common in these patients but not universal. So
what happens when an
intraparenchymal hemorrhage occurs? Well, the first thing is
blood extravasates
from the blood vessel from the ruptured artery and this
results in development of a focal
neurologic deficit. And these patients really present with
focal neurologic deficits
or stroke-like symptoms in addition to headache. Headache is
common, but not universal.
02:33
It's much more common to see headache with an
intraparenchymal hemorrhage or
hemorrhagic stroke as opposed to a ischemic stroke. As that
blood extravasates into
the brain, there is adjacent brain tissue that is disrupted
or displaced or compressed
from local mass effect and swelling and deep hemorrhages
occur in the same regions as
lacunar infarcts. So we see hemorrhages in the caudate and
putamen, in the thalamus,
in the pons, or in the cerebella. Now let's talk about
intraventricular hemorrhage.
03:00
in the pons, or in the cerebella. Now let's talk about
intraventricular hemorrhage.
03:06
Intraventricular hemorrhage is bleeding or blood that forms
from intracerebral bleeding in
which there is blood in the ventricular system. This is the
least common cause of
intracranial hemorrhage, it's uncommon. And we see 2 types,
primary intraventricular
hemorrhage or secondary intraventricular hemorrhage. Primary
IVH accounts for only
about 3% of spontaneous intracranial hemorrhage so it's
really rare. It may also occur
secondary. You may have IVH secondary to subarachnoid
hemorrhage, intraparenchymal
hemorrhage, or any other type of intracranial hemorrhage. It
can complicate those
presentations. Patients present with symptoms of increased
ICP, blood within the ventricles
results in reduced CSF reabsorption. So we see increased
intracranial pressure,
symptoms of nausea, vomiting, headache and ultimately
impaired consciousness.
03:57
Complications include obstructive hydrocephalus or cerebral
vasospasm particularly when
IVH is associated with subarachnoid hemorrhage. And we
consider similar management
strategies to other types of intracranial hemorrhage. We
want to reduce blood pressure
and prevent hemorrhage propagation but with IVH we have to
be worried about
hydrocephalus. These patients may need interventions to
manage increased ICP such as
external ventricular drains like an EVD or other management
strategies to reduce increase
in intracranial pressure and manage ICP. Now let's talk
about the second step in
causes of intraparenchymal hemorrhage. Now let's talk about
step 2 in evaluating
patients with an intracranial hemorrhage. The second step is
working up the cause of the
intracranial or intraparenchymal hemorrhage. And here we can
consider 6 major
categories that cause intraparenchymal hemorrhage. And many
of these categories
arise from risk factors for increase in intraparenchymal
hemorrhage. That includes
hypertension, hematologic disorders, disorders to increase
likelihood of bleeding,
cerebral amyloid angiopathy can increase the risk of
bleeding anticoagulant use,
alcohol use or abuse can increase the risk of particularly
subdural hematoma formation
both with and without trauma, and vascular abnormalities
that are present on the brain.
05:13
The 6 categories I like to think about that are causes of
intraparenchymal hemorrhage
are hypertension, hemorrhagic transformation of an ischemic
infarct, amyloid angiopathy,
vascular lesions such as an AVM or aneurysm, tumor formation
or tumor-like metastasis
or primary brain tumors, and then there are a number of
other causes like trauma,
vasculitis, Moyamoya disease, and others. And these
categories help me to think
about the causes of the hemorrhage, what I need to do to
evaluate them and ultimately
the management strategy.