Walsh & Hoyt: Orbital Inflammatory Syndrome

Inflammatory conditions involving the orbit, including abscesses and the nonspecific condition called idiopathic inflammatory pseudotumor or idiopathic orbital inflammatory syndrome, may also cause anterior compression of the proximal optic nerve and secondary disc swelling that can be confused with primary optic nerve tumors. Associated posterior scleritis may also cause disc swelling. Affected patients usually experience acute or subacute visual loss, pain, proptosis, and congestion associated with the optic disc swelling, possibly with retinal vein occlusion. The presence of an orbital process is rarely in question. Infrequently, meningiomas of the orbital apex produce a similar clinical picture. CT scanning and MR scanning usually show thickening and enhancement of normal tissues or a mass lesion. Ultrasound can be very helpful in the identification of posterior scleritis and thickening of Tenons capsule and the sclera. The pain and rapid evolution of symptoms generally distinguish orbital inflammatory disease from the more indolent course characteristic of most orbital tumors. Most of these patients respond rapidly to systemic steroid treatment.