0:01

This patient had a change in mental status associated

0:04

with nystagmus and some element of a tremor.

0:09

On the FLAIR scan that was performed,

0:12

you can see that there is high signal

0:14

intensity bilaterally and symmetrically

0:17

in the medial thalamic region, as well as

0:19

on either side of the third ventricle.

0:23

When you look a little bit more inferiorly,

0:24

maybe I can convince you that there is some

0:26

high signal intensity in the periaqueductal

0:29

gray matter of the midbrain as well.

0:34

The dentate nuclei look fine.

0:36

The remainder of the brain is normal.

0:39

On the diffusion-weighted scans, a little bit of

0:43

bright signal intensity in the paraventricular thalamic

0:47

region around the third ventricle and bilaterally,

0:53

this abnormality did not show contrast enhancement.

0:57

But on the T1-weighted scan, I think you do get a

1:00

sense of the low signal intensity on T1-weighted

1:02

imaging in the medial thalamic region bilaterally.

1:06

On this type of patient, it moves yourself to

1:09

go into the electronic medical record and try to find

1:12

what the patient's symptomatology and history was.

1:16

In this case, this was a patient who had had previous

1:20

bariatric surgery for obesity and was having a

1:24

difficult time taking down food after the surgery.

1:29

What you are seeing is a characteristic pattern

1:32

of a patient who has thiamine deficiency.

1:36

It is a disease which typically affects bilateral

1:40

medial thalamus, mammillary bodies, and periaqueductal

1:45

gray matter. That abnormality may show restricted

1:50

diffusion and may show contrast enhancement.

1:55

The restricted diffusion and the contrast enhancement

1:59

is more common in thiamine deficiency associated

2:02

with alcoholism and alcoholic encephalopathy.

2:05

In patients who have it on a dietary basis

2:09

for something like anorexia nervosa or

2:12

bariatric surgery, it is less common to see

2:15

restricted diffusion or contrast enhancement.

2:18

But this is an important entity to recognize.

2:22

Bilateral, mediothalamic, mammillary

2:24

body, and periaqueductal gray matter.

2:27

I should have pointed out the mammillary

2:29

bodies, they actually are pretty

2:29

strikingly bright on this FLAIR scan.

2:32

Let's go back to the diffusion-weighted

2:34

imaging and see how bright they are.

2:37

Yeah, big, bright mammillary bodies, my bad.

2:41

In this situation, you have to identify for the

2:45

clinicians that this is a likely etiology for the

2:48

patient's mental status changes because if this is

2:52

not corrected in a short amount of time, in days to

2:55

weeks, this patient will go on to permanent neurologic

2:59

deficit in a syndrome called Wernicke-Korsakoff psychosis.

3:03

56 00:03:05,000 --> 00:03:08,060 As you can imagine, this is a bad encephalopathy

3:08

associated with psychotic behavior that is permanent if

3:12

the thiamine deficiency is not corrected within days.

3:16

The radiologist, the neuroradiologist, is

3:19

often the person who suggests this diagnosis

3:22

because it's not apparent to the clinicians

3:26

that the patient has thiamine deficiency.

3:29

So once again, mediothalamus,

3:32

periaqueductal gray matter, mammillary body

3:36

involvement symmetrically, is indicative of

3:41

thiamine deficiency until proven otherwise.

3:45

Are there other manifestations of thiamine deficiency?

3:47

Yes.

3:48

You may see it in the medial temporal

3:51

lobes, you may see it involve the dentate

3:53

nucleus, and you may see it also involve the

3:56

perirolandic gray matter and white matter.

4:00

Those are other areas in less common

4:02

locations for thiamine deficiency.