Which is the least likely cause in this patient with retrobulbar swelling and diplopia?
Oral contraceptive use
Differential swelling with periorbital swelling: NOAHH’S ARK
- Nephrotic syndrome
- Orbital celllulitis (look out for postseptal cellulitis)
- Allergy, angioedema
- Hoagland sign of infectious mononucleosis
- SVC syndrome
- Autoimmune (dermatomyositis)
- Romana’s sign of Chagas disease
- Kavernous sinus thrombosis
However, not all causes of periorbital swelling will cause retroorbital swelling and proptosis.
When seeing proptosis, think of:
- Grave disease
- Retro-orbital infection (intracranial infection which spreads through inferior orbital fissure, ethmoidal or sphenoidal sinusitis)
- Retro-orbital inflammation eg Tolossa-Hunt syndrome (granulomatous inflammation of sinus cavernous), retro-orbital pseudotumour (linked with vasculitis eg Wegener granulomatosis, PAN and connective tissue diseases eg RA, SLE, dermatomyositis)
- Retro-orbital neoplasm/pseudotumour
- Retro-orbital vascular diseases (sinus cavernous thrombosis, carotid-cavernous fistula, aneurysm)
In this patient, unilateral swelling with diplopia with red patch around the eye suggests vascular congestion leading to pressure in optic nerve and muscles running in retro-orbital compartment.
– Without a history of trauma, vascular causes should be considered. She was found to have sinus cavernous thrombosis.
The least likely cause is dermatomyositis. Unilateral heliotrope rash has been described but rarely it causes diplopia.