This is a 2 year old male who presents with a chief 
complaint of bilateral eye swelling.  He had some 
swelling noted 2 weeks prior to this admission and was 
treated with antibiotics for a presumed sinusitis.  The 
swelling did improve to some degree; however it never 
completely resolved.  Over the past 2 weeks the 
swelling has worsened.  There has been some itching 
but no fever.  His vision is unaffected as far as his 
mother could tell.  Diphenhydramine and erythromycin 
ophthalmic ointment were started and once again the 
swelling improved.  They present today because the 
swelling is again worse.  Mom denied any trauma to the 
lids or orbit, no eye discharge, and only mild redness.  
There are no symptoms to suggest hyperthyroidism.
     His past medical history is negative for any diseases 
of the eyes, severe allergies, renal or cardiac disease, 
or thyroid dysfunction.  His family history is 
unremarkable.
     Exam.  He is a healthy appearing male who has mild 
proptosis of both eyes.  There is mild conjunctival 
erythema but no discharge.  The corneas are clear.  No 
erythema of the lids is appreciated.  Anterior chambers 
are clear and extraocular movements are conjugate but 
not fully testable, though the Doll's eye maneuver was 
normal.  There is no preauricular lymphadenopathy.

     At this point, what is your working differential 
diagnosis?  a) non-accidental trauma, b) accidental 
trauma, c) hyperthyroidism, d) periorbital or orbital 
cellulitis, e) orbital malignancy (e.g., retinoblastoma), f) 
other.

     How would you proceed?  a) visual acuity testing, b) 
complete blood count, c) eye culture, d) ophthalmology 
consult, e) all of the above.

     Answer:  e) all of the above.  Culture of the eye 
discharge or conjunctiva is needed to rule out bacterial 
conjunctivitis.  Blood work for thyroid function and 
complete blood count (CBC) is useful to check for other 
etiologies of the proptosis and for the possibility of 
hematologic malignancy.  Visual acuity testing should 
be done in every case of symptoms related to the eye.  
Ophthalmology is needed because of the possibility that 
surgical intervention my be indicated.

     His visual acuity is probably normal, but this is 
difficult to test well in a 2 year old.  His CBC is normal 
and eye cultures were obtained.  An ophthalmology 
consult was obtained and a CT of the orbits is ordered.

View CT scan.


     What does the CT show?  Does this alter your 
differential?  What should be done now?

     The CT of this child's orbits reveals thickening of the 
orbital structures.  Thickening/swelling of the 
extraocular muscles is most evident.  No calcifications 
are noted.  The globes are normal and no bony 
erosions are noted.  The remainder of the study is 
normal.  These findings are consistent with orbital 
pseudotumor.



     The arrows here point to the enlarged extraocular 
muscles resulting in anterior displacement of the globe.
Although the arrows point fo just some of the lateral and 
medial rectus muscles, ALL the extraocular muscles are 
enlarged.

Discussion:
     Orbital pseudotumor (OP) or idiopathic non-specific 
orbital inflammation is a non-infectious acute 
inflammation of the orbits, that presents with orbital 
swelling or a mass.  It is usually unilateral, but it may be 
bilateral as it was in this case.  It is uncommon in 
children but it has been reported in children as young 
as 3 months of age.  OP may present as proptosis, eye 
pain, ptosis, lid edema, conjunctivitis with or without 
chemosis (swelling of the conjunctiva) and limitation of 
extraocular movements.  Fever, headaches and eye 
discharge may be found.  Orbital involvement is 
generally unilateral and recurrences may occur.  
Sometimes one can palpate a mass above the temple 
or under the orbital rim.  Autoimmune disorders have 
been associated with this condition.  The differential 
diagnosis includes orbital cellulitis, orbital abscess, 
tuberculoma, hematoma, inflammation secondary to 
systemic disease such as Grave's disease, sarcoidosis, 
a retained foreign body, leukemia, lymphoma, optic 
neuritis, tumors (primary, metastatic and pseudo).
     To establish a diagnosis, ultrasonography and/or 
CT of the orbits is often necessary.  Special laboratory 
studies such as markers for rheumatoid disease or 
thyroid dysfunction may also be helpful.  The CT 
typically demonstrates diffuse anterior orbital 
inflammation next to the globe with scleral and 
choroidal thickening.  Enlargement of the extraocular 
muscles may also be seen on either ultrasound or CT 
scan.
     After an imaging diagnosis is made, a biopsy may 
be necessary to rule out leukemia or lymphoma.  The 
histopathology of orbital pseudotumor shows 
polymorphic lymphocytic and plasmacytic infiltrates with 
eosinophilia.  Corticosteroids are the mainstay of 
therapy.  Once started, the symptoms quickly resolve 
as they did in our case.  In fact, the response to 
steroids is so pathognomonic, that the diagnosis is 
often made retrospectively based on the response.  A 
poor response indicates the need for biopsy.


References
     Grossniklaus HE, Lass JH, Abramowsky CR, Levine 
MR.  Childhood orbital pseudotumor.  Ann Opthalmol 
1985;17(6):372-377.
     Sirbaugh PE.  A case of orbital pseudotumor 
masquerading as orbital cellulitis in a patient with 
proptosis and fever.  Ped Emerg Care 
1997;13(5):337-339.