0:01

This was a child in which I'm going to show you

0:04

three separate studies over the course of time.

0:07

This was the initial presentation of the

0:09

child who was being evaluated for an enlarged

0:13

head circumference as part of the pediatric

0:17

evaluation of the child in the first year of life.

0:21

And what we see is marked enlargement

0:23

of the lateral ventricles.

0:26

We want to sort of try to give an estimate of

0:28

why this patient has big ventricles, and for that,

0:32

we will look at the sagittal scan and identify

0:36

whether or not there appears to be a web at

0:38

the cerebral aqueduct as a source of lateral

0:41

ventricular and third ventricular enlargement.

0:43

In this case, the fourth ventricle also

0:46

appears to be enlarged, and there is a large

0:48

CSF space below the cerebellum. So, this

0:50

is more likely to be a communicating

0:53

hydrocephalus, which could occur secondary

0:56

to perinatal bleeding at the time of birth,

0:59

or meningitis, or a functional obstruction

1:02

for whatever reason in the arachnoid villi.

1:05

The next study that was performed was the

1:08

study that was done after the patient had

1:11

placement of the ventriculostomy catheter.

1:15

So, the ventriculostomy catheter has been inserted

1:19

in the occipital region on the right side.

1:22

In general, ventriculostomies are placed

1:25

on the right side because that's usually the

1:27

non-dominant hemisphere, and usually, they come

1:30

through the parietal occipital region because

1:33

that has fewer functional potential problems than,

1:37

for example, inserting it through the frontal

1:40

lobe, where you may affect the motor strip.

1:42

36 00:01:42,570 --> 00:01:46,995 So, ventriculostomy catheter has been placed initially

1:46

after placement of the ventriculostomy catheter.

1:49

We don't expect very much change

1:51

in the ventricles in this child.

1:53

We're not seeing a lot of transpendymal CSF

1:56

flow, which suggests that this is a chronic.

1:58

Hydrocephalus.

2:00

It's not as if there's an acute

2:01

obstruction of the ventricles.

2:03

This is a longstanding process in, in this

2:07

particular child, probably from a perinatal

2:09

injury that led to the ventricular enlargement.

2:13

They don't want to rapidly decompress the ventricles.

2:17

'Cause if they were to do so rapidly, it

2:20

sometimes will tear the bridging veins.

2:23

And whenever you hear the term "tearing of

2:25

the bridging veins," you might think about

2:27

subdural hematomas.

2:28

So, if you decompress the ventricles quickly,

2:32

what happens is you rip those bridging veins

2:34

'cause suddenly they're collapsing inward, and

2:37

you can lead to bilateral subdural hematomas.

2:41

So here, this is the appropriate location of

2:44

the ventriculostomy with no significant

2:47

change in the lateral ventricular system.

2:50

The patient presented shortly

2:53

thereafter with mental status changes.

2:57

And here is the problem.

2:59

This is the same patient who has the

3:03

ventriculostomy catheter here in the occipital

3:05

region, and the ventricles are really small.

3:08

Now, you might say, "Oh, that's a good thing.

3:10

You know, they treated the hydrocephalus."

3:13

But what happened?

3:14

You've got these big subdural collections bilaterally

3:18

now, and this is what is referred to as overdrainage.

3:24

Of the lateral ventricles.

3:26

In this case, whatever the pressure setting that was

3:29

placed for the pressure in the ventriculostomy catheter

3:34

was too low, and that led to collapse of the ventricles.

3:39

And as I said, when that happens, you get these

3:42

subdural collections because of issues with hydrostatic

3:45

pressure and potentially ripping of the bridging veins.

3:48

Now, this looks predominantly like CSF, so these may be

3:52

subdural hygromas rather than

3:55

hematomas from the blood products.

3:57

But in any case, this is secondary to over-

4:00

drainage of the lateral ventricles in a

4:02

patient who had chronic hydrocephalus.

4:05

We actually don't want to see these small ventricles.

4:08

We wanna see larger ventricles

4:11

that allow the hydrostatic pressure

4:13

between what's in the brain versus what's

4:16

outside the brain to be in equilibrium.

4:19

So, when you're looking at patients for shunt failure,

4:23

you can have shunt failure because the patient's

4:25

ventricles blow up and the shunt is obstructed.

4:30

But you may also have shunt failure from over-

4:33

drainage, slit ventricle syndrome, which may lead to

4:38

patient symptomatology and/or subdural collections.