0:00

When we are considering infectious inflammatory

0:04

disease of the extraconal space,

0:08

we must consider the possibility that the etiology

0:11

is from the paranasal sinuses.

0:14

Our first case,

0:15

we saw that the etiology was a skin infection which

0:18

is also a common source of periorbital cellulitis.

0:23

In this case, it's pretty clear that the patient has opacification

0:27

of the left ethmoid sinuses.

0:30

One sees on the axial scans the infiltration of the ethmoid

0:35

sinus with inflammatory disease and opacification.

0:39

This patient has a mild amount of proptosis of

0:44

the left eye compared with the right eye.

0:47

On the coronal image,

0:49

we see that the orbital fat shows injection suggesting

0:53

that there is edema within the intraconal space.

0:56

This is one of the markers of orbital cellulitis.

1:01

On the axial scan, at the insertion site of the optic nerve,

1:05

we see some edema that is in the orbital fat and we also see

1:10

some irregularity to the posterior membranes of the globe,

1:15

all of which implies the possibility of orbital cellulitis.

1:20

In the Chandler classification of infections of the orbit,

1:25

type one represents the preseptal periorbital cellulitis.

1:31

Type two represents the postseptal orbital cellulitis.

1:36

Type three represents a periorbital abscess and this is seen

1:43

in this case medial to the medial

1:48

rectus muscle on the left side.

1:51

Here we have a collection which has developed its low density

1:56

seen anteriorly and it is spreading from that ethmoid sinus

2:01

which is the source of the orbital cellulitis

2:04

as well as the periosteal abscess.

2:08

On these soft tissue windows on the coronal image,

2:11

one can see what appears to be a small area of

2:15

dehiscence along the lateral orbital wall,

2:18

which is the communication with the ethmoid sinus.

2:23

And then we see the fluid collection which is in the

2:27

extraconal space and in the left medial orbit.

2:34

The fourth of the Chandler classification is a true orbital

2:38

abscess where the infection usually resides

2:42

within the intraconal space of the orbit.

2:45

And the fifth classification for Chandler classification

2:48

five is cavernous sinus involvement, endor thrombosis.