Vascular dementia - causes, symptoms, diagnosis, treatment, pathology

Speaker: With Vascular Dementia, vascular
refers to the blood flow to the brain,

and dementia refers to problems like
poor memory, difficulty communicating,

and difficulty learning new information.

Vascular Dementia is also known as
Multi-Infarct Dementia.

And it's progressive loss of brain
function, caused by long-term poor

blood flow to the brain, typically because
of a series of strokes.

Okay, let's start with some basic brain
anatomy.

The brain has a few regions.

The most obvious is the cerebrum, which
is divided into two cerebral hemispheres,

each of which is divided into four lobes.

The frontal, parietal, temporal, and
occipital lobe.

The frontal lobe controls movement, and
our personalities.

It also handles our ability to count, and
spell, and make decisions.

The parietal lobe processes sensory
information, which lets us locate exactly

where we are physically, and guides
movements in a 3-dimensional space.

The temporal lobe plays a role in hearing,
smell, and memory.

As well as visual recognition of faces
and languages.

Finally, there's the occipital lobe, which
is primarily responsible for processing

visual information.

All the cells in the body need oxygen, but
that's particularly relevant for neurons,

which can only function in aerobic
conditions, meaning with a constant

supply of oxygen.

Neurons also don't have long-term
energy storage, so, they need a constant

supply of glucose to keep working.

Each time the heart beats, about a quarter
of the blood pumped out goes directly

to your brain by the internal carotid
arteries, and the vertebral arteries in

the neck.

Once they reach the base of the brain,
these arteries join to form a ring called

the Circle of Willis.

Which then branches off into smaller
and smaller arteries.

The smallest being the perforating
arteries that eventually supply the

entire brain with oxygen and glucose.

Vascular Dementia develops in some
individuals when atherosclerosis starts

to form in the arteries.

That's when there's a buildup of plaque
that thickens and hardens the artery wall.

When this process affects the artery
supplying the brain, like the carotid

arteries, it leads to a gradual decrease
in blood flow to the brain, which is

called Chronic Ischemia.

Sometimes, small parts of the plaques can
break away, and these bits can drift up

towards the brain, and can then eventually
block a smaller artery, completely

stopping the blood supply to the part of
the brain that's supplied by that artery.

Other times, tiny perforating arteries are
affected by atherosclerosis, and can

get completely blocked off by plaque
growing within them.

Regardless of the cause, once blood
supply to the brain falls below the

demands of the tissue, it's considered an
Ischemic Stroke.

The tissue damage from an Ischemic Stroke
is usually permanent, because the tissue

gets damaged and the dead tissue liquifies
in a process called liquefactive necrosis.

Brain tissue necrosis leads to a loss of
brain functions governed by that area.

If another stroke happens later on, more
brain tissue might die off, and over time

this damage gets worse and worse.

The final result is dementia, a persistent
loss of mental functions, that is severe

enough to effect a persons daily
functioning.

Symptoms of Vascular Dementia vary
depending on which region of the brain

is damaged.

For example, if someone has strokes in
the temporal lobe, it might be difficult

for them to remember things, or make
new memories.

Someone with a stroke in the left
parietal lobe might lose the ability

to speak, which is called Aphasia.

But, then if they get another stroke in
the frontal lobe, their personality might

begin to change.

One thing that's constant is that the
symptoms of dementia appear suddenly,

and brain function decreases with each
stroke.

Neuropsychological tests, like the mini
mental state exam, can be used to

confirm that there is a loss of brain
function.

The vascular cause can be diagnosed using
brain imaging.

Most commonly CT or MRI, which will show
multiple or subcortical infarcts, and

changes like atrophy of the brain cortex,
confirming the ischemia.

Currently, there's no cure or medication
to help specifically with

Vascular Dementia.

Treatment focuses on reducing the risk
of repeated strokes.

This means treating conditions like high
blood pressure, high cholesterol, and

reducing smoking.

Alright, as a quick recap, Vascular
Dementia is a progressive loss of

brain function, caused by multiple strokes
or infarcts, which in turn are caused by

atherosclerosis of the blood vessels
supplying the brain.

The signs and symptoms depend on
where the strokes develop, and they

usually appear one at a time.

Treatment currently focuses on treating
underlying conditions, which may prevent

further strokes from happening.

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