0:00

This is a 45-year-old patient who was on

0:04

medications for the chemotherapy

0:07

for testicular carcinoma.

0:09

The FLAIR scan and the T2-weighted scan

0:11

are being presented.

0:12

As we scroll from the posterior fossa,

0:16

we see on T2-weighted scan that things

0:18

look pretty good.

0:20

However,

0:20

once we extend into the supratentorial white matter,

0:23

we notice that there is abnormal signal

0:25

intensity in the periphery of the occipital

0:28

and parietal lobes,

0:30

and coursing further in superiorly,

0:33

we see the involvement

0:34

of the frontal lobes as well.

0:37

This involvement,

0:38

which is symmetric from side to side

0:40

and has a posterior predilection,

0:42

is characteristic of

0:44

Posterior Reversible Encephalopathy Syndrome.

0:47

As described previously,

0:48

there are many medications that can cause PRES,

0:52

Posterior Reversible Encephalopathy Syndrome,

0:55

and withdrawal of these medications usually will

0:58

resolve the PRES within a matter of weeks,

1:03

and that is demonstrated on the MRI scan.

1:05

Within a matter of days,

1:07

usually, the patient is already

1:09

showing clinical improvement.

1:10

So the medications that we are particularly

1:12

concerned with are Cyclosporine, Tacrolimus,

1:15

FK 509, Ara-A, Ara-C.

1:17

You may also see this with Tysabri,

1:21

which is one of the medications that is

1:23

associated with multiple sclerosis treatment.

1:28

But there are any number of medications

1:31

that can lead to PRES,

1:33

and you just have to look them up.

1:34

By and large,

1:35

they are chemotherapeutic agents

1:37

and immunosuppressive agents,

1:39

as well as some of the medications

1:42

used for infection.

1:44

So with this involvement that is bilateral and symmetrical,

1:47

we're going to think about PRES.

1:49

The other thing that can simulate PRES is one

1:53

of these reversible vasoconstrictive syndromes.

1:57

This is an entity in which a patient presents

1:59

with a thunderclap headache,

2:02

and again,

2:03

has wide swings in the blood pressure and may be

2:08

associated with atypical subarachnoid hemorrhage.

2:11

By atypical subarachnoid hemorrhage,

2:13

I mean hemorrhage that is out in the periphery

2:16

rather than at the basal cisterns.

2:18

Certainly, when we think of thunderclap headache

2:21

with subarachnoid hemorrhage

2:23

of the basal cisterns,

2:25

we worry about aneurysm perforation and aneurysm

2:28

bleeding and aneurysm rupture as the source

2:31

for that severe headache associated

2:33

with subarachnoid hemorrhage.

2:35

The subarachnoid hemorrhage that's occurring

2:37

with reversible vasoconstrictive syndrome is

2:40

usually more in the periphery and is not

2:43

at the basal cisterns and therefore,

2:45

is less concerning for a patient who

2:48

has an aneurysm bleed.

2:51

However,

2:51

this may lead to white matter changes that

2:55

are mediated through the hypertension

2:57

and vasoregulatory mechanism.

3:01

Cerebral vasoconstrictive system

3:03

that's reversible,

3:05

is more commonly seen in women and actually

3:08

has a very good prognosis.

3:10

In general,

3:11

the patient does not have long term negative

3:14

consequences from the prognosis.

3:17

And similarly,

3:19

early treatment of PRES leads to reversal of

3:24

the encephalopathy and return to normal health.