Here, we’ll take a look at degenerative
diseases of the basal ganglia.
And by definition, if the basal
ganglia has been affected,
you can expect there to
be movement disorders
including rigidity, abnormal
posturing or even chorea,
all items that we’ve
talked about prior.
The diseases that are associated with
degenerative disease of the basal ganglia
include obvious parkinsonism,
progressive supranuclear palsy,
We’ll talk about multiple
systemic type of atrophies
and then we’ll end by looking at our
postencephalitic type of parkinsonism.
We’ll begin our discussion of degenerative
diseases of the basal ganglia
by looking at Parkinsonism.
The definition of which
will be a clinical syndrome
characterized by diminished
and by that we mean a masked facies.
Next, it might be stooped posturing
and if you take a look at the
hands, there’s resting tremor
and there is this pill-rolling
that’s taking place.
Literally, it looks like
Now, let’s talk about this gait.
Well, at first, the gait here, the
feet feel as though for the patient
that the feet are stuck
in cement or quicksand.
So therefore, very difficult to
start the initial step or gait.
Once the gait has now
begun or commenced,
then it’s almost like the patient
is now taking these petite march
or a little march.
Little steps to gain,
to gain momentum.
So you have these little steps that
are being taken by the patient,
which are now in
We call this a shuffling gait.
We call this a Parkinson gait and this
is then known as your festinating gait.
And we talked about the pill-rolling
and we talked about the posture.
Now, parkinsonism, remember
that it’s the dopamine
for whatever reason that
is now being diminished.
And it will be a damage that’s taking place
to the nigrostriatal dopaminergic pathway
and nigro- of course
referring to the dark nature
that you would find in the substantia nigra
and the less of that nigra
or darkness that you find,
this would then correlate
to the amount of dopamine
that is also being
diminished or lost.
Here, we’ll take a look at
idiopathic Parkinson disease.
It’s progressive parkinsonism
and the absence of toxic or any
other real underlying issue.
The classic features:
Well, we talked about
the resting tremor.
Bradykinesia, rigidity, and by
that we mean, cogwheel rigidity,
difficulty with --
it’s almost like your knife.
If you take your pocket knife and
you have that closing of the knife,
the clasping of the knife,
when you’re about to close it,
that’s what you’re going to
have, the cogwheel rigidity.
Masked facies, expressionless
as we talked about.
And then at some point
in time, unfortunately,
dementia may set in
25% of your patients.
well, we said that referring
to the substantia nigra
and if that nigra portion, meaning
to say that dark entity or feature
that you’d find that represents the
supply of dopamine starts getting lost,
that means your dopamine supply is also
being lost resulting in abnormal movement.
Predominantly sporadic, although well-recognized
familial cases have also been shown.
Acute Parkinson’s syndrome and destruction
of neurons in substantia nigra
follows exposure to something called
Also been known to perhaps accelerate
the presentation of Parkinson's.
The clinical pathology
that you’d find with
disease, as you can imagine,
instead of having that
nigra, you have pallor
of the substantia nigra
and locus ceruleus.
the loss of pigmented catecholamine
neuron associated with gliosis.
And, well, once upon a time,
the second most common cause
of dementia in the U.S. is
a condition known as
Lewy body dementia.
And at that time, when I
showed you Lewy body,
I told you within that Lewy body,
there’s something called synuclein.
Well, please understand that you could find
Lewy body here in Parkinson’s as well.
Can you give me one clinical pearl that
you’ll find with Lewy body dementia
that you may or may not see
with Parkinson disease?
And you should be thinking about
ha-Lewy-cinations with Lewy body dementia.
Now, with Parkinson, you
will also find Lewy body,
round to elongated inclusions
that often have a dense core
surrounded by a pale halo.
I’ll show you the
picture once more.
The picture that you see
here is a Lewy body,
and within it, you see this
circular eosinophilic structure.
That is particular referring
to your synuclein,
something that we also pointed out
to you or that I pointed out to you,
in Lewy body dementia.
Let’s talk about the management,
please, of Parkinson disease.
Well, in essence, what
are trying to do here?
You want to try to either slow down
the deficiency of that dopamine,
or maybe perhaps even replace
the dopamine itself.
And you think about the
nigrostriatal type of pathway
and all the different ways in which
dopamine can be delivered to it.
This is something that you
talked about in pharmacology.
Please keep in mind that whatever dopamine
that you’re able to swallow orally,
you want to try to inhibit
the enzyme in the stomach
so that you can properly deliver
the dopamine up into the brain
because that’s where you
want this, don’t you?
Let’s take a look.
So dopamine cannot cross the BBB.
It cannot cross the blood-brain barrier.
L-Dopa is the most effective treatment.
L-Dopa can be converted
into dopamine in the brain,
even if the dopaminergic
neurons are dying.
That’s something that you
want to keep in mind.
Now, a dopamine agonist can
also be used for the following:
Less potent than L-Dopa.
Less motor side effects.
And more cognitive behavioral side effects
such as hallucinations that
might be taking place,
and by that, we
mean the following:
Remember that Parkinson’s disease
is a deficiency of dopamine.
On the other end of the spectrum,
if there was excess dopamine,
then obviously we are now
referring to psychosis.
Interesting, isn’t it?
Your focus at this point, in this
particular section, is levodopa.