Lid/Orbit
Idiopathic Orbital Inflammatory Disease
Also known as: orbital pseudotumour, IOID, idiopathic orbital inflammation, orbital myositis, orbital pseudotumor, non-specific orbital inflammation, IOIS, painful proptosis adult
Filed as: Urgent
Source-cited from the record's own evidence list. Clinical content programme led by Dr Ankit Mathur, PhD, Grad Cert Ocu Thera, B.S. Optom. How the clinical content is governed
Clinical decision support only
Overview
A non-specific idiopathic inflammatory process affecting any structure within the orbit — the most common cause of painful proptosis in adults. Also known as orbital pseudotumour or idiopathic orbital inflammatory syndrome (IOIS). Can involve the lacrimal gland (dacryoadenitis), extraocular muscles (orbital myositis), the posterior orbit (posterior IOID), or diffuse orbital fat. Usually unilateral. Characteristically responds dramatically to systemic corticosteroids.
Recognition
Symptoms: what patients report
- Acute onset painful proptosis — the most typical presentation.
- Periorbital pain — often severe.
- Diplopia from extraocular muscle involvement (orbital myositis subtype).
- Lid swelling and erythema.
- Reduced vision if optic nerve is compressed.
- Unilateral in most adult cases.
- Lacrimal gland swelling: S-shaped ptosis, fullness in the upper outer orbit.
Signs: what the examination shows
- Proptosis: variable degree — often acute onset.
- Lid erythema and oedema.
- Conjunctival chemosis and injection.
- Restricted and painful eye movement — particularly painful on eye movement in the direction of the affected muscle.
- Palpable firm mass in the orbit or lacrimal fossa.
- Lacrimal gland enlargement: S-shaped ptosis and upper outer lid fullness.
- Reduced visual acuity or RAPD if optic nerve is involved.
- CT scan: diffuse orbital infiltrate, lacrimal gland enlargement, or muscle thickening extending to the tendon insertion (distinguishes from TED).
What OptoGuide™ covers for idiopathic orbital inflammatory disease
- Pattern reasoning: what this combination of findings points to, and its differentiators
- Don't-miss risks and escalation triggers
- Management tiers with linked Australian therapeutics
- Referral urgency, specialty, and letter drafting
Sources
- Nonspecific Orbital Inflammation (Orbital Pseudotumor) — EyeWiki
- A 55‐year‐old woman with orbital inflammation. Schwab P, Harmon D, Bruno R, Fraunfelder FW, Hyunchung Kim D. Arthritis Care & Research. 2012;64(11):1776-82.
- Pediatric orbital lesions: non-neoplastic extraocular soft-tissue lesions. Gerrie SK, Rajani H, Navarro OM, et al. Pediatric Radiology. 2024;54(6):910-921.
- Clinical Reasoning: Young Woman With Orbital Pain and Diplopia. Infante R, Donadio V, Nucera B, et al. Neurology. 2020;94(7):e752-e757.
Standard texts: Kanski's Clinical Ophthalmology: A Systematic Approach, The Wills Eye Manual, Oxford Handbook of Ophthalmology, Oxford American Handbook of Ophthalmology, Signs in Ophthalmology: Causes & Differential Diagnosis.