0:00

This was a 44-year-old homeless person

0:04

who was brought in by the police

0:07

after loss of consciousness.

0:10

As we scroll through this case,

0:13

we see that there appears to be midline

0:16

shift at the level of the

0:19

septum pellucidum.

0:22

Let's measure that.

0:29

It measures 7 mm,

0:32

and therefore, is significant left-to-right shift.

0:36

The question is,

0:37

what is the cause of that left to right shift?

0:41

Sometimes it could be due to volume loss

0:43

on the right side due to atrophy.

0:45

But we are not seeing

0:47

subarachnoid space dilatation on the right side.

0:54

As we continue to scroll further superiorly,

0:57

we're not seeing a parenchymal hematoma.

0:59

We are seeing some bowing of the falx subtly

1:03

up anteriorly.

1:05

You'll might note that the subarachnoid space,

1:09

overlying the right frontal convexities medially,

1:12

is demonstrated,

1:13

but not on the left side.

1:16

So this is a quandary.

1:18

What is the source of that midline shift?

1:23

Well, hopefully, you would have identified that

1:27

the juxtacortical white matter,

1:30

which is going far out to the periphery on the right

1:34

side and in the occipital region on the left side,

1:38

does not extend to the periphery as far on the left side.

1:45

Let me use my magic pen.

1:48

What I'm talking about is this amount of white matter,

1:52

inward displacement compared to the white matter

1:58

on the right side, is one of the markers

2:02

for an isodense subdural.

2:04

And you can see that actually the cortical margin on the

2:09

left side is located where I've

2:12

drawn my arrow and my line.

2:15

Although, you do not see a hyperdense collection in this

2:19

individual, by virtue of the displacement inward of the

2:24

Juxtacortical white matter, the degree of mass effect,

2:28

and in some cases, the effacement of the sulci,

2:32

that this patient has an isodense subdural hematoma.

2:36

Now,

2:37

this patient may have lost consciousness days ago

2:41

and been found subsequently, and therefore,

2:43

we could identify this as a subacute in age isodense

2:49

subdural, or we would check the hematocrit,

2:51

see whether the patient is anemic,

2:53

in which case, it would be potentially an acute

2:56

isodense subdural hematoma.

2:58

No matter what,

2:59

if we were to measure this,

3:01

we would find that the collection is 13 mm thick,

3:05

exceeding the 10 mm thick criteria for surgical intervention.

3:11

And that, as well as the 7 mm of midline shift,

3:15

would lead the neurosurgeons to intervene in this patient.