0:01

Whenever we are considering periorbital

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cellulitis or orbital cellulitis,

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we may also consider the entity of orbital pseudotumor,

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also known as idiopathic orbital inflammation.

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The reason why these are difficult differential diagnoses

0:17

is that both may be associated with orbital pain,

0:20

both may be associated with orbital chemosis,

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and both may be associated with orbital erythema.

0:27

The difference is that orbital pseudotumor

0:30

is usually treated with steroids,

0:31

whereas periorbital cellulitis will be treated with antibiotics.

0:35

And therefore, you have to make that distinction.

0:37

With respect to orbital pseudotumor,

0:40

it can affect any part of the orbit.

0:42

In this case,

0:43

we see the inflammation over the eyelid, as well

0:48

as affecting the anterior chamber and cornea.

0:51

But the patient also has scleral thickening and some element

0:56

of infiltration of the orbital fat, which might suggest

1:00

orbital cellulitis.

1:01

This is where the clinical evaluation to look for a source of

1:05

infection on the skin surface or the

1:08

paranasal sinuses is critical.

1:11

As I mentioned,

1:12

orbital pseudotumor can affect nearly every portion of the

1:16

orbit, including the eyelids, including the lacrimal gland,

1:20

including the lacrimal sac.

1:22

However, the most common form of it infiltrates as a mass in the orbit,

1:28

most commonly affecting the lacrimal gland,

1:32

or it can affect the muscles of the orbit, and we discussed how

1:37

they will affect the muscular tendons, as opposed

1:39

to that with thyroid eye disease.

1:42

You note that orbital pseudotumor can be a source of

1:45

optic neuritis, scleritis, and eyelid inflammation.

1:51

This is a disease entity which is usually quite painful

1:56

and the patients are in distress.

1:59

Treatment begins with steroids. However, if the steroids are ineffective,

2:04

low-dose radiation therapy, usually less than 2000 rads,

2:08

is sufficient for the treatment of orbital pseudotumor.

2:13

The next in line of therapy would be immunosuppressives, and then

2:17

rarely, if it is a mass, one can remove it with surgery.