00:01
In this lecture we will discuss
autoimmune attacks on the CNS.
00:06
We'll talk about Guillain-Barre Syndrome
and Acute Disseminated Encepahlomyelitis.
00:12
Let's start with
Guillain-Barre Syndrome.
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So, Guillain-Barre is an autoimmune
antibody attack
on the peripheral nerve roots.
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Typically, this is an attack on the
myelin sheet of the nerve.
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Usually, there is a preceding infection,
something like diarrhea.
00:30
Especially,
Campylobacter can cause it.
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Also, patients can get mycoplasma
pneumonia infections
and then subsequently have Guillain-Barre
Syndrome.
00:41
General viral respiratory illnesses
can trigger the problem.
00:45
And vaccination can to, especially
influenza vaccination.
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So, how does
Guillain-Barre present?
Generally patients have
an acute weakness.
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This acute weakness has a typical pattern of
ascending.
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It starts with leg weakness,
and gradually proceeds
up to the body to the arms
and eventually to the cranial nerves.
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The progression usually happens
over a period of a few days.
01:15
And it may lead to respiratory
failure,
which is when people really get into trouble.
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The weakness is symmetric in that
both legs
and both arms should be equally affected.
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Generally, deep tendon reflexes should be
diminished or absent.
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Because of the nerve root.
01:35
And pain is common.
This can be a very painful condition.
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Autonomic dysfunction is possible
and this can be dangerous.
01:44
Patients can develop cardiac arrhytmias
They may get urinary retention.
01:48
And they may develop
gastroparesis.
01:52
One side type
of Guillain-Barre Syndrome is
the Miller-Fischer variant
of Guillain-Barre Syndrome.
02:00
This may happen
as the isolated finding or it may happen
in the context of a patient with this
gradually ascending paralysis.
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The key for Miller-Fischer variant is
opthalmoplegia or paralysis
of the eye muscles.
02:17
Here, you can see this child being
asked to look about the room
is having great difficulty moving
his eyes.
02:25
Weakness commonly begins in this case
in the cranial nerves.
02:30
And patients may have the triad of
Ataxia, and Areflexia,
but then also,
Ophthalmoplegia
but arm and leg weakness occur in
the minority of these cases.
02:43
Most just have the eye findings.
02:46
Back to Guillain-Barre Syndrome.
02:49
If we have a patient where we have
suspected the key test to get
is the spinal tap.
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In patients with
Guillain-Barre Syndrome,
typically, there will have a normal
white cell count
and a very elevated protein level.
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This is sometimes called
Albuminocytologic dissociation.
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That's a fancy way of saying,
the albumin or protein is high but
the cell count is normal.
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Remember, normally in meningitis,
we see both being elevated.
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If we proceed to MRI because
we are suspicious of Guillain-Barre Syndrome,
the MRI may well show enhancement
of the nerve roots
and we can also do if we wish,
specific antibody testing
to see whether the patient has antibodies
directed
against to their nerves
Additionally, if a diagnosis really needs
to be made, in most cases
we don't really need to go this far,
patients can get nerve conduction studies
to try and figure out
the speed at which electrical signals
are going through those nerves.
03:52
It should be delayed with patients
wtih myelin damage.
03:57
Generally for
Guillain-Barre Syndrome,
steroids are not helpful.
04:03
IVIG is.
04:05
And so we'll give Intravenous Immunogobulin
to patients with
Guillain-Barre Syndrome.
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This is effective. It slows progression
and it speeds up recovery.
04:16
We want to watch these patients
very carefully.
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And to do that, we get something
called NIFs
This is done typically on the wards
or in the ICU setting.
04:27
So, what is a NIF?
A NIF
is a Negative Insperatory Flow.
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The patient is asked to breathe all
the way out and breathe in
as rapidly as they can.
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This is the measure of the patients ability
to sustain respiration.
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And will check baseline NIFs and
as they decline,
we know we're moving closer and closer
towards the need
for respiratory support or intubation.
04:54
Pulse oximetry is not effective
for screening.
04:57
Because the oxygen is the last thing
to go.
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Mechanical ventilation
is needed often in these patients
who are severe for respiratory failure.
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We will intubate them and generally wait
for the illness to resolve
and they can be safely extubated and
hopefully recover fully.
05:16
And the vast majority do recover
fully.
05:19
95% of these patients will eventually
make a full recovery.
05:24
But
that recovery may take months.
05:27
So, we have to be patient
and wait for the child to improve.
05:31
Let's switch gears here to Acute
Dissemintated Encephalomyelitis.
05:37
or ADEM.
05:39
ADEM
is a brief but intense disease. It is an
autoimmune attack on the brain
and the spinal cord.
05:47
And these antibodies are against
again on myelin.
05:51
It is often preceded by a viral infection
usually one or two weeks later.
05:56
And maybe a precursor
to multiple sclerosis.
06:00
You can think of this a little bit
like MS in children.
06:06
ADEM is usually a rapid onset problem,
where patients are fine and then
rapidly develop encephalitis
or central nervous system
symptoms.
06:17
Weakness may be present or a
sensation of pain
is present.
06:21
If they have spinal cord lesions
as well, which they may or may not.
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Sometimes, this can be a confusing
picture.
06:29
Because the problem as the name suggests
is disseminated.
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And can be spotty.
06:35
So, certain areas of the
brain are affected but
not others and that could lead to
very unique neurologic patterns
in terms of symptomatology
Optic nerve involvement can happen
and patients may have
vision problems as well.
06:50
Here you can see a typical
brain MR for patients with ADEM.
06:54
And you can see several spots
highlighted by the arrows
where inflammation is occuring.
07:00
A brain and spine MRI is indicated
if you suspect ADEM.
07:05
Because involvement can happen anywhere
along the brain and the entirity
of the spine.
07:10
The MRI is diagnostic for demyelinization.
07:14
And with a spotty picture
the diagnosis is made.
07:17
In ADEM,
unlike
in Gullain-Barre,
steroids are helpful and are the mainstay
of treatment.
07:26
IVIG or plasmaphoresis maybe helpful.
It is unclear right now.
07:32
Good studies haven't really been done.
But in severe cases we may move on to that
as an act of desperation to try and help
the child improve.
07:41
Recovery usually happens over a period
of usually 1-2 months.
07:45
But unlinke Guillain-Barre Syndrome,
which has a very high rate of recovery
While many children recover,
not all do.
07:52
Generally, between 60-80% will
have a recovery.
07:56
And a small minority
may be at risk
for eventually developing
multiple sclerosis.
08:02
That's all I have for today about acute
disseminated encephalomyelitis
and Gullain-Barre Syndrome.
08:08
Thanks for your attention.