0:00

We're going to continue in the differential

0:03

diagnosis of demyelinating disorders.

0:06

The next entity I'd like to talk about is

0:08

acute disseminated encephalomyelitis.

0:11

This is a diagnosis that is more frequently

0:14

created or diagnosed in children than it is in adult.

0:19

It is a typically monophasic disorder,

0:24

although it can have recurrences.

0:27

It typically occurs within two to four weeks

0:30

after a viral infection or immunization.

0:34

Therefore,

0:35

because children are getting vaccinated more

0:37

commonly than adults and also getting viral

0:40

infections more commonly than adults,

0:42

it is seen more commonly in children.

0:44

This is an autoimmune disorder that is thought

0:47

to be a delayed type hypersensitivity

0:50

reaction to myelin basic protein,

0:52

leading to an attack on the white matter.

0:55

It, like multiple sclerosis,

0:57

can affect the brain, can affect the spine,

1:00

and is in the differential diagnosis for

1:02

cases of optic neuritis as well.

1:05

There is a more aggressive form that may be

1:08

hemorrhagic and that is much more fulminant

1:12

and has a worse prognosis.

1:15

On this slide,

1:17

anything that's labeled with a P

1:19

refers to pediatric variety of ADEM,

1:22

whereas anything that refers to an A is the

1:25

adult variety of ADEM.

1:27

So, as you can see,

1:29

cortical involvement occurs much more frequently

1:32

in pediatric cases than in adult cases,

1:36

whereas periventricular white matter involvement

1:39

is more common in the adults than the children.

1:42

Deep gray matter involvement,

1:44

by that, we're usually talking about

1:46

the basal ganglia and the thalami,

1:48

as opposed to in the cerebellum,

1:50

is more frequent in children.

1:52

Brain stem involvement and cerebellar involvement,

1:55

more frequent in children.

1:57

Spinal cord ADEM does occur.

2:00

When it occurs,

2:01

it is more frequent in children

2:02

than in the adult population.

2:04

That involvement of deep gray matter is the

2:08

distinguishing feature between it

2:11

and other demyelinating disorders,

2:13

including multiple sclerosis.

2:15

Here we have a patient who has a much

2:17

more fulminant fluffy disease,

2:20

as opposed to the Dawson fingers-like appearance

2:24

in the periventricular location

2:26

of multiple sclerosis.

2:28

What one is seeing is involvement

2:30

of the thalamus

2:33

in this case,

2:35

as well as the subcortical white matter

2:37

going out to the cortical surface of the brain.

2:41

We don't really see those classic sort of flame

2:44

shaped demyelinating lesions

2:46

of multiple sclerosis in this individual,

2:49

and in this case,

2:50

we are not seeing any evidence of

2:53

contrast enhancement.

2:54

However,

2:55

just like multiple sclerosis,

2:57

ADEM may show contrast-enhancing lesions.

3:01

Another entity to describe is something

3:05

that is affectionately called MDEM.

3:07

Why is it called MDEM?

3:09

Well, we said that ADEM generally is a monophasic

3:13

disorder that occurs at one point.

3:16

However, if you have recurring bouts of ADEM,

3:20

you may hear them use the term multiphasic

3:25

disseminated encephalomyelitis,

3:27

which is a recurrence of potentially ADEM

3:31

that occurs after steroid withdrawal

3:33

or further infection.

3:35

And one thing you should recognize

3:38

is that ADEM is an autoimmune disorder

3:42

with an attack against the white matter,

3:44

as is multiple sclerosis,

3:46

and sometimes this blurring of the distinction

3:50

between ADEM and MDEM

3:52

and subsequently multiple sclerosis

3:55

because you have recurring neurologic events,

3:59

clinically distinct events that occur over time

4:03

with an MRI pattern that will be showing periventricular

4:08

and subcortical,

4:09

as well as cortical lesions that are typical

4:12

of multiple sclerosis, as well as ADEM.

4:17

So it may be that we are looking at a spectrum

4:21

of disorders that may be elicited by viral

4:25

infections that includes ADEM,

4:28

MDEM and multiple sclerosis,

4:31

and which leads to an autoimmune

4:33

attack on the white matter.

6:03

We're going to continue in the differential

6:06

diagnosis of demyelinating disorders.

6:08

The next entity I'd like to talk about is

6:11

acute disseminated encephalomyelitis.

6:14

This is a diagnosis that is more frequently

6:17

created or diagnosed in children than it is in

6:22

adults. It is a typically monophasic disorder,

6:27

although it can have recurrences,

6:30

it typically occurs within two to four weeks

6:33

after a viral infection or immunization.

6:37

Therefore,

6:38

because children are getting vaccinated more

6:40

commonly than adults and also getting viral

6:43

infections more commonly than adults,

6:45

it is seen more commonly in children.

6:47

This is an autoimmune disorder that is thought

6:50

to be a delayed type hypersensitivity

6:53

reaction to myelin basic protein,

6:55

leading to an attack on the white matter.

6:58

It, like multiple sclerosis,

7:00

can affect the brain, can affect the spine,

7:02

And is in the differential diagnosis for

7:05

cases of optic neuritis as well,

7:08

there is a more aggressive form that may be

7:11

hemorrhagic and that is much more fulminant

7:15

and has a worse prognosis.

7:18

On this slide,

7:20

anything that's labeled with a p refers

7:22

to pediatric variety of ADEM,

7:25

whereas anything that refers to an A is the

7:28

adult variety of ADEM. So, as you can see,

7:32

cortical involvement occurs much more frequently

7:35

in pediatric cases than in adult cases,

7:39

whereas periventricular white matter involvement

7:42

is more common in the adults than the children.

7:45

Deep gray matter involvement,

7:47

by that we're usually talking about

7:49

the basal ganglia and the thalami,

7:51

as opposed to in the cerebellum,

7:53

is more frequent in children.

7:55

Brain stem involvement and cerebellar

7:57

involvement more frequent in children.

8:00

Spinal cord ADEM does occur.

8:03

When it occurs,

8:04

it is more frequent in children

8:05

than in the adult population.

8:07

That involvement of deep gray matter is the

8:11

distinguishing feature between it and

8:14

other demyelinating disorders,

8:16

including multiple sclerosis.

8:18

Here we have a patient who has a much

8:20

more fulminant fluffy disease,

8:23

as opposed to the Dawson fingers-like appearance

8:27

in the period of triculocation

8:29

of multiple sclerosis.

8:31

What one is seeing is involvement

8:33

of the thalamus

8:36

in this case,

8:38

as well as the subcortical white matter going

8:41

out to the cortical surface of the brain.

8:44

We don't really see those classic sort of flame

8:46

shaped demyelinating lesions of multiple

8:50

sclerosis in this individual,

8:52

and in this case,

8:53

we are not seeing any evidence of

8:56

contrast enhancement. However,

8:58

just like multiple sclerosis,

9:00

ADEM may show contrast enhancement.

9:03

Lesions.

9:04

Another entity to describe is something

9:08

that is affectionately called MDEM.

9:10

Why is it called MDEM?

9:12

Well,

9:12

we said that ADEM generally is a monophasic

9:16

disorder that occurs at one point.

9:19

However, if you have recurring bouts of ADEM,

9:23

you may hear them use the term multiphasic

9:28

disseminated encephalomyelitis,

9:30

which is a recurrence of potentially ADEM that

9:34

occurs after steroid withdrawal

9:36

or further infection.

9:38

One thing you should recognize is that ADEM is

9:43

an autoimmune disorder with an attack against

9:46

the white matter, as is multiple sclerosis,

9:49

and sometimes this blurring of the distinction

9:53

between ADEM and MDEM and subsequently multiple

9:58

sclerosis because you have recurring

10:00

neurologic events clinically.

10:02

Distinct events that occur over time with an MRI

10:08

pattern that will be showing periventricular

10:11

and subcortical,

10:12

as well as cortical lesions that are typical

10:15

of multiple sclerosis as well as ADEM.

10:20

So it may be that we are looking at a spectrum

10:24

of disorders that may be elicited by viral

10:28

infections that includes ADEM,

10:31

MDEM and multiple sclerosis,

10:34

and which leads to an autoimmune

10:36

attack on the white matter.