Orbital inflammation.

Orbital inflammation is a common problem in adults and children, accounting for the majority of all orbital processes. The presentation may be acute, subacute, or insidious. When the onset is acute, the process can be mistaken for orbital cellulitis. In insidious cases, such as the sclerosing subtype of inflammation, the chronic painless course may prompt concerns about a neoplastic infiltration such as lymphoma. Orbital inflammation can be divided into nonspecific, idiopathic, and other specific diagnoses. The differential diagnosis includes allergic, infectious (fungal, mycobacterial, and parasitic), and neoplastic (lymphoma or metastatic) disease. Orbital inflammation impacts neurologists and neuro-ophthalmologists because all of the entities can cause afferent dysfunction (decreased vision, abnormal color perception, afferent pupillary defect, and visual field defect) and dysmotility. The pattern of motility deficit may mimic the more familiar cranial nerve palsies. Advances in the diagnosis and management of nonspecific orbital inflammation and the specific entities that cause orbital inflammation are discussed.