Orbitopathies inflammatoires. Que doit savoir l'interniste ?

Inflammatory orbitopathies relate to an inflammatory state originating within the orbit and its adnexes, except the inner ocular globe. Orbital inflammation (OI) may be either localized manifestation of a proven or like autoimmune disease, or local response from immune system against infectious, structural or tumoral antigens. We review the clinical manifestations of OI, which provide helpful clues to the diagnosis and describe the inflammatory, infectious and neoplastic conditions classically associated with OI. Autoimmune diseases are probably the most common causes of OI associated with a bilateral dacryoadenitis (e.g., sarcoidosis, granulomatosis with polyangiitis, IgG4-related disease). We focused on a major part of the IgG4-RD spectrum, the IgG4-related orbital disease which has been recently described and the idiopathic orbital inflammation syndrome that one should consider in patients 40 years of age or older with non specific inflammation OI on biopsy but without underlying local or systemic disease. An algorithm for the diagnostic approach of OI was proposed. If systemic explorations fail to diagnose an underlying disease, histopathologic control is required for distinguishing non-specific OI from other differential diagnosis, especially lymphoma. In the cases of pure myositic locations and posteriorly located tumours where biopsy could damage to the optic nerve, analysis of orbital lesions in T2W IRM sequence may be helpful to distinguish idiopathic OI (IOI) from lymphoma. When the diagnostic work-up fails, a corticosteroid trial could be used, but its beneficial effect has to be cautiously interpretated before definitively diagnosing IOI. Finally, treatments used in main infllammatory orbitopathies were also reviewed.