0:00

This was a patient who is being evaluated

0:03

for nuance at epilepsy,

0:05

for which they had recently started antiepileptic drugs.

0:09

As you scroll through the case

0:11

with the FLAIR image,

0:12

the T2-weighted scan and the

0:14

diffusion-weighted scan,

0:16

what one sees,

0:18

especially well demonstrated on

0:21

the diffusion-weighted scan to the right,

0:24

is an area of abnormal signal intensity within

0:26

the splenium of the corpus callosum.

0:29

This is not so well identified on the FLAIR image,

0:33

as better seen on the T2-weighted scan,

0:35

but certainly the diffusion-weighted scan

0:37

is pretty striking.

0:39

We look for the ADC map of the same patient,

0:43

and you can see the dark signal intensity of the

0:47

cytotoxic edema of the splenium

0:49

of the corpus callosum.

0:51

I'm referring to this dark signal intensity on

0:53

the ADC map,

0:55

corresponding to the DWI signal intensity change,

0:59

and you note that the FLAIR images are not

1:02

as dramatic, but it is present there.

1:05

As we scroll through the rest of the scan,

1:08

we really see relatively little on the FLAIR

1:13

and the rest of the diffusion-weighted scan.

1:15

There's a little bit of high signal intensity in

1:17

the periphery of the splenium

1:18

as it goes out into the forceps minor...

1:22

forceps major there.

1:24

Focal splenium demyelination and cytotoxic edema

1:29

elicits a broad differential diagnosis.

1:33

Within that differential diagnosis,

1:35

we include seizures...

1:36

epilepsy can do it,

1:39

but in addition,

1:40

administration and institution of antiepileptic drugs,

1:44

particularly Keppra drugs,

1:46

can lead to a focal area of splenium

1:49

cytotoxic edema demyelination.

1:51

So, both the institution and withdrawal of Keppra

1:56

related antiepileptic drugs are responsible for

2:00

splenium demyelination examples.

2:03

However,

2:04

the splenium may also be involved in cases

2:07

of ischemic injury to the white matter.

2:11

This would be either on a dominant anterior

2:14

cerebral artery or a posterior cerebral

2:17

artery focal infarction.

2:19

That's pretty unusual not to have some

2:21

cortical involvement, however.

2:23

We also see focal splenium involvement in cases

2:27

of trauma where there is diffuse axonal injury

2:30

injuring the splenium.

2:32

Strangely enough,

2:33

that diffuse axonal injury from trauma

2:36

can lead to cytotoxic edema.

2:39

There are multiple other causes of

2:42

focal splenium demyelination,

2:44

including things such as hepatorenal syndrome.

2:48

You can see it sometimes with posterior

2:49

reversible encephalopathy syndrome or PRES,

2:52

and you may also see it in patients who have

2:56

progressive multifocal leukoencephalopathy,

2:59

but usually it's much more extensive than this.