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OP2.6 | Proptosis: Causes, Differentiation and Management — SDL Guide (Part 3)

Management of Proptosis

The management of proptosis is fundamentally the management of the underlying cause. No single proptosis treatment algorithm exists — each cause has its own evidence-based pathway. However, two management principles apply universally regardless of aetiology.

Universal Principle 1 — Corneal protection: Any degree of proptosis that produces incomplete eyelid closure (lagophthalmos) risks exposure keratopathy, which can progress to corneal ulceration, melting, and permanent visual loss. All patients with proptosis should be assessed for lagophthalmos by asking them to close their eyes gently and observing for inferior corneal exposure. Management steps: (a) preservative-free lubricating drops during the day; (b) lubricating ointment and moisture chamber at night; (c) lid-taping at bedtime if significant lagophthalmos; (d) urgent referral if corneal exposure ulcer develops.

Universal Principle 2 — Protect the optic nerve: Serial colour vision and visual acuity at every review. Any deterioration = emergency pathway regardless of cause.

Cause-specific management summaries:

• Thyroid eye disease: The most common cause. Management is detailed in the OP2.3 SDL. In brief: active inflammatory phase → systemic immunosuppression (IV methylprednisolone, rituximab); compressive optic neuropathy → urgent orbital decompression; sight-threatening corneal exposure → urgent tarsal strip or temporary tarsorrhaphy. Rehabilitative orbital decompression for cosmetic proptosis is performed only after disease activity has settled for ≥6 months (EUGOGO guidelines). Teprotumumab (anti-IGF-1R antibody) has shown promise in active moderate-to-severe TED.

• Orbital cellulitis: IV antibiotics (see OP2.4 SDL). Subperiosteal abscess on CT → surgical drainage if visual compromise or failure to improve on IV antibiotics within 48 hours.

• Cavernous haemangioma: Observation if asymptomatic and vision normal. Surgical excision (lateral orbitotomy) if proptosis is progressive, vision is threatened, or cosmesis is unacceptable. The lesion has a well-defined pseudocapsule and is surgically accessible. Excellent prognosis.

• Rhabdomyosarcoma: Oncological emergency in a child. Step 1: urgent incisional biopsy under general anaesthetic for histological diagnosis. Step 2: immediate paediatric oncology referral. Treatment: combination chemotherapy (VAC protocol — vincristine, actinomycin D, cyclophosphamide) ± radiotherapy. Survival rates exceed 90% for localised disease with modern protocols.

• Orbital lymphoma: Systemic staging (PET-CT, bone marrow biopsy) to determine whether localised or systemic. Low-grade localised orbital lymphoma: orbital radiotherapy. Systemic lymphoma: chemotherapy (CHOP or equivalent).

• Dermoid cyst: Elective surgical excision. Ruptured dermoid causes intense granulomatous inflammation and should be operated urgently to remove all cyst contents.

• Orbital metastasis: Palliative intent in most cases; orbital radiotherapy for pain relief and visual preservation; systemic oncology management.

Compressive optic neuropathy — the emergency: Loss of colour vision or visual acuity in a patient with proptosis is an ophthalmic emergency. In TED: pulse IV methylprednisolone (500 mg daily × 3 days); if no improvement in 1–2 weeks, urgent surgical orbital decompression (removal of bony orbital walls to expand orbital volume). In malignant proptosis: steroids may buy time while oncological management is initiated.

Self-Assessment

Review the following questions to consolidate your understanding of this module. These questions are at the level expected in ophthalmology clinical examinations and the NMC professional assessment.

1. A 7-year-old boy presents with a 10-day history of rapidly progressive proptosis with downward and forward displacement of the right globe, periorbital erythema, and no fever. CT shows a heterogeneous soft-tissue mass in the superior orbit with early bony remodelling. What is the single most important next management step?

2. Enumerate the causes of bilateral proptosis in an adult. Which single cause accounts for the majority of bilateral cases?

3. A 50-year-old man has left proptosis measuring 24 mm on Hertel (right eye 19 mm). He is euthyroid, TRAb is negative, and CT shows a well-defined enhancing mass at the superolateral orbit conforming to the lacrimal gland fossa without bone erosion. What is the most likely diagnosis, and what is the single contraindicated investigation?

4. Name the instrument used to measure proptosis, state the normal upper limit, and specify the clinically significant asymmetry threshold.

5. What is pseudoproptosis? Give two causes.

Answers:

1. Urgent incisional biopsy under general anaesthetic and immediate paediatric oncology referral — this is rhabdomyosarcoma until proved otherwise.

2. Bilateral proptosis causes: thyroid eye disease (most common by far — >80% of bilateral adult orbital disease), orbital lymphoma, bilateral metastases, cavernous sinus lesions (thrombosis, fistula), Wegener's granulomatosis/GPA. Thyroid eye disease accounts for the majority.

3. Pleomorphic adenoma of the lacrimal gland. The contraindicated investigation is incisional biopsy — biopsy of a pleomorphic adenoma seeds tumour cells into the orbit and significantly increases the risk of malignant transformation and local recurrence. Planned total excision with an intact capsule is the definitive procedure.

4. Hertel exophthalmometer. Normal upper limit: 20 mm (some sources 21 mm). Significant asymmetry: >2 mm difference between the two eyes.

5. Pseudoproptosis is apparent forward displacement of the globe without true proptosis on Hertel measurement. Causes include: contralateral enophthalmos (making the normal eye appear prominent), ipsilateral lid retraction (as in TED, exposing sclera above the limbus), high axial myopia (physically larger globe displaced forward), buphthalmos (enlarged globe in congenital glaucoma).