Video summary
The video provides a comprehensive overview of the inflammatory spectrum affecting the central nervous system, focusing primarily on multiple sclerosis (MS) and its differentiation from other demyelinating conditions. In MS, lesions are typically characterized by short segment involvement, rarely extending beyond two vertebral levels, and often appear eccentrically within the spinal cord. A key diagnostic nuance discussed is that approximately one-third of patients may present with isolated spinal lesions without any brain findings, meaning the absence of brain lesions does not rule out an MS diagnosis. Consequently, clinical guidelines emphasize that whenever a demyelinating lesion is seen in the spinal cord or brain, the other region must be screened to ensure a confident and complete diagnosis.
The presentation then shifts to Neuromyelitis Optica Spectrum Disorder (NMOSD), formerly known as Devic's disease, which is a severe autoimmune condition driven by antibodies against aquaporin-4. These antibodies target specific perivascular astrocytes, leading to distinct imaging patterns such as longitudinally extensive transverse myelitis affecting three or more vertebral segments and characteristic "fluffy" lesions around the ventricles and brainstem. The transcript highlights a crucial distinction between NMOSD and Myelin Oligodendrocyte Glycoprotein (MOG) antibody-associated disorders; while NMOSD often presents with posterior optic nerve involvement that may be cosmetically less severe, MOG-associated cases frequently show anterior optic nerve damage that can be disfiguring. Additionally, conditions like Acute Disseminated Encephalomyelitis (ADEM) are described as monophasic inflammatory events often triggered by viral infections or vaccinations, typically presenting with prodromal symptoms and multifocal lesions that differ from the relapsing-remitting nature of MS.
Finally, the discussion covers Transverse Myelitis as a focal inflammatory disorder causing motor, sensory, and autonomic dysfunction at a specific spinal level. Diagnostic criteria for this condition require imaging evidence of extensive involvement, affecting more than two-thirds of the spinal cord's cross-sectional area, along with clinical signs like clear sensory levels and spinal cord enlargement on MRI. The video concludes by distinguishing these inflammatory myelopathies from vascular causes, noting that while MS involves a waxing and waning course, conditions like ADEM are usually monophasic, and transverse myelitis can result in varying degrees of permanent disability depending on the severity of the initial attack. Throughout the presentation, the speaker stresses the importance of comprehensive imaging protocols that include screening both the brain and optic nerves to accurately classify these complex disorders within their respective diagnostic criteria.
Read the full video transcript
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[Music] So let us see the inflammatory
spectrum first starting with what all do
we see in this inflammatory
spectrum of disorders. So most commonly
the autoimmune once consist of multiple
sclerosis tumors, demyelinating
lesions in the brain which is commonly seen as
neuromyelitis optica a dem which is an
acute disseminated encephalomyelitis
and antimog associated encephalomyelitis.
So when we start with multiple
sclerosis here we have
this T2 hypertension legion with
this spinal cord which are short
segments in involvement. So they will not be
involving more than the length of two vertebral
levels and the vertebral body lens. On a
transverse section, you will see that they can have any kind
of pattern of involvement,
but usually it is in the dorsal part of the
spinal cord. Generally it is eccentric
involvement. It is not always that the
patient will have symptoms. One third of
patients may have symptoms of spinal
involvement while two thirds may simply be
asymptomatic.
So that is one thing. 1/3 of patients may have
only isolated spinal multiple
sclerosis without any findings in the
brain. So it's not that if you don't see the
lesions in the brain that doesn't mean that it wo
n't classify into multiple sclerosis.
So 95% of people with multiple sclerosis
have spinal cord injury whether they have
spinal symptoms or not. So we know that when
you have demyelination.
In the brain parenchyma on your brain
MRI you always screen the spinal cord.
Similarly, if you are just doing spinal
cord imaging and if you see this lesion.
Always Screen Brain at Least with One 3D
Flare Sequence. So that you can make a
confident diagnosis. So, short segment
involvement is the characteristic of
multiple sclerosis. On actual sections,
you see that there is eccentric
involvement. In cases of multiple
sclerosis. However, it can be anywhere on
the actual sections. So, two uncommonly seen but
typical features are also seen with multiple
sclerosis.
Later on, it can progress to spinal
cord atrophy over a long period of time,
and specifically, it is seen with the primary
progressive form of multiple
sclerosis. Now coming to NMO
neuromyelitis optica. So this is an
autoin demyelinating disease as we know the other
name to it is Dewick's disease. It
preferentially affects the optic nerve and
the spinal cord and is more prevalent in females than
males. So the triad, the routine,
what we have learned is optic neuritis,
longitudinally extensive myelitis and
positive NMO Ig. But everything has
evolved a lot in this particular
spectrum of disorders based on our
understanding of the pathophysiology of the
disease. So this is a severe autoimmune
inflammatory demyelinating disorder of the
CNS and the role of autoinhibition in the
pathogenesis of NMO was established
in 2004 after the discovery of aquaporins
for Ig immunoglobulins. So as our
understanding of the disease pathophysiology
grew we knew how to classify and also
imaging wise now we know it better based on
the pattern of involvement of various
structures. So in this seropositive
group existing autoin disorders have been
recognized and now the term which is
used is NMO spectrum disorder. So that's this is
the new term NMO SD.
So what is this aquaporin for which we always talk about
whenever we talk about
NMOs. So aquaporin 4 is the main
aquaporin in the brain and is expressed
in the highest density in perivascular and
subpylaminar astrocytes and feet. So that is the
specific location for this area and
afterwards we will understand because of this
particular involvement of this disease we have
a pattern on imaging and also some
symptoms like intractable hiccups,
vomiting, nausea etc. So, this is
just one graphic representation of the
timeline over which the terms kept
changing. So earlier it was just NMO
NMO Criteria and then it was NMO
SD which was introduced and finally
in 2015 the latest criteria were
introduced as International Panel for
NMO Disorders and Diagnosis. So the
diagnostic criteria for aquaporin
P4 Ig positive cases are different. The ones
which are IG negative are different. So, we need not like kind of remember everything.
But whenever you have a case falling into this
particular spectrum, it would be a good
practice if you could actually refer to these
criteria and give your
recommendations for what further has to be done in these
cases.
So, if we see what are the MR
criteria, then, there are some core
clinical criteria and there are some
imaging criteria here. So if we see the
four clinical criteria may be like
optic neuritis features of myelitis hiccups nasia
vomiting based on
involvement of area postma syndrome but
what are the MR features so you have to have
acute optic neuritis which means that if you are
suspecting this you should always
screen the optic nerves as well so at
least coronal ster images should be obtained
through the optic nerves. So, in any kind
of demyelination spectrum of disorders.
Even if the referring physician has asked for
only brain or only spine, you should always talk
to them and try to convince them for a
brain, at least spine screening, and
at least optic nerve screening so that you have
a complete picture of the disease and its
distribution.
So brain MRI may show normal findings
and non-specific findings but optic
nerves will show up to hypertensive signal which may enhance after
contrast. Acute
myelitis may be seen as a presenting symptom in
legions extending over three or more months.
So long segment involvement
of the spinal cord and spinal cord
atrophy may also be seen. There will be
involvement of dorsal medulla and
peripendial brain stem lesions may also be
seen in this condition. So, This Is What the
Distribution Looks Like. What we have
seen is the distribution of the Aquap poring
p folk. And because of that particular
distribution the legions also have a
specific pattern. So if you see on the
sagittal image very typical perependymal
surface involvement. On actual this kind
of perependymal lateral ventricular surface
involvement. Then this diencephalic region of
the third ventricle peri aqueductal area
and then lesions in the optic chiasma also
peri ependymal surface of the fourth ventricle
and area postma these are some kind
of typical appearance in
this ennemo sd spectrum marble pattern
this kind of fluffy margins with arch
bridge appearance and in the spinal cord
bright spot lesions with long spinal
cord segments of involvement. Again there are
differences between ah i aquaporin P4
Ig four positive status and MOG antibody
which is MOG Ig positive status
where we have a different pattern of
involvement in the optic nerve spinal cord
brain as well as the way we have the
enhancement. So in optic nerve
involvement of your Ig for ectopic there
is superficial long length involvement and
posterior involvement is seen which is
usually cosmetic but in cases of antimog
antibodies you have anterior involvement
severe disfiguring and perineural
enhancement we will see few examples as well.
So as we discussed ah there will be long
segment of spinal cord abnormality.
These additional sections will show bright spot
lesions on T2 and patchy cloud-like
enhancement. This is the typical pattern of
enhancement in these cases of NMO SD.
Periventricular confluent white matter
involvement. Peri aqueductal gray matter
involvement. Dorsal pons. Dorsal medulla. That is
what the typical features look like
and also always screen the optic nerves
next coming to the adamam which is another
condition commonly involving the spinal
cords. So acute disseminated
encephalomyelitis.
So this is an inflammatory demyelinating
disorder which is usually seen after
viral infections or vaccination. You will have an
acute presentation to a subacute
presentation. Usually these people and these
kids they come from emergency and you have to
ask for some history of viral illness.
Mostly they have some prodromal features, some
GI related viral infection and some other
viral infection history is always there.
These are typically monophasic but there is
literature evidence of biphasic involvement
of IDM as well. And in many of these cases, up
to 50% of antimog IDD tests are
positive. And there has been literature talking about them
developing a future spectrum of
NMO SD disorders.
So as we discuss there are different patterns
of involvement of NMO SD and MOG
antibodies. So this is the graphic
representation of the same. The way optic
nerves are involved. So cosmetic
involvement is more with NMO spectrum
and with antimog. This is more like optic
nerve involvement. And the rest of it we have
already discussed.
Ah moving ahead ah with the details of a
deep. So as most commonly seen we have
multifocal spinal cord lesions in the
spinal cord in EdM plus additional brain
lesions asymmetric lesions are more common than
symmetric lesions in the brain parenchyma as always
mentioned screen the cranio spinal
access don't leave just with spinal cord
and brain images this is how typical EdM
looks like and ah most common setting in your
emergency referral one of the most common
diagnosis is EdM with proper clinical
history and imaging features. So what is the
difference between ADM and MS?
Edm usually have prodromal face ms they don't have
it. ADM will be associated with
altered sensorium as I mentioned then
commonly seen meningismus which is not seen
with MS. Butterfly optic neuritis is
commonly seen with AD. However, it is most
commonly unilateral with MS. You can have
complete transverse myelitis. You can have
seizures, ataxia. So it is quite
symptomatic and monophasic. However,
multiple sclerosis may not be so
symptomatic, but definitely relaxing, waxing and waning
is what we actually
understand from the pathophysiology of
multiple sclerosis.
Coming next to transverse myelitis.
So we saw multiple sclerosis, NMO
spectrum ADM and now coming to
transverse myelitis. So these are focal
inflammatory disorders of the spinal
cord resulting in motor sensory and
autonomic dysfunction. So you will have a
clinical
point and clinical picture where they will give you
a level of the spinal cord
involvement that the symptom is from D10
levels. The symptom is from the fourth level.
Some clinical inputs will be there. Well they have
a straight ah clear level of spinal
cord involvement clinically. So that is why
the name transverse myelitis. Two on
imaging the involvement will be diffused
long segment.
So what are the imaging criteria? More
than 2/3 of the cross sectional area has to be
involved. There has to be focal symptoms of
enlargement of the spinal cord and
to hypertension lesions which may or may not enhance.
So, how do we ah kind of ah see two
types of transverse melits are there.
So one is your acute partial transverse
myelitis. The other is acute complete
transverse myelitis. So Legion if they are
extending more than two segments it is
complete. If it is less than two segments that is
partial.
Initial MR abnormalities are usually
extensive but 1/3 of cases may just
completely resolve. 1/3rd of them have severe
disability and 1/3rd can have moderate degree
of permanent disability. So there are defined
inclusion and exclusion
criteria for multiple serotypes for
transverse myelitis including as we mention
clearly defined sensory levels
clinically will be there plus what is more is
development of sensory motor
autonomic dysfunction due to spinal
cord pathologies dural signs and symptoms
and CSF pleocytosis may be seen exclusion criteria
includes radiation
to spine arterial distribution and
abnormal flows because then that becomes
a vascular malformation and dural AVF
related pathology. So that is one thing in
case of transverse meristem. Other
inflammatory lesions which can involve the
spinal cord are like this. Nodular
peripheral enhancing lesions, meningeal
enhancement and spinal cord T2
hyperintensity as may be seen with sarcoid.
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so