E-Pearl of the Week: Idiopathic Orbital Inflammatory Syndrome (IOIS)

September 6, 2011


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September 6, 2011

Idiopathic Orbital Inflammatory Syndrome (IOIS)

Idiopathic orbital inflammatory syndrome (IOIS) or orbital pseudotumor, is a rare disorder which is likely an autoimmune disorder mediated by both B and T lymphocytes. It can mimic orbital cellulitis or optic neuritis with an acute presentation of unilateral eye pain, diplopia, vision loss, photophobia, proptosis, and conjunctival injection. MRI is the imaging modality of choice that can show enlargement of extraocular muscles or enhancement around the globe. IOIS is a diagnosis of exclusion and a thorough evaluation for systemic etiologies should first be performed. The mainstay of treatment is corticosteroids. Radiation, methotrexate, cyclophosphamide, or cyclosporine could be considered for refractory cases.


  1. Jacobs D, Galetta S. Diagnosis and management of orbital pseudotumor. Curr Opin Ophthalmol 2002;13: 347-351.

Submitted by:
Ganesh Asaithambi, MD, and Ellie Eun Ju Choi, DO

Disclosures: Drs. Asaithambi and Choi report no disclosures.

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