Exophthalmos

Specialty: Endocrine and metabolic.

• proptosis
• thyroid ophthalmopathy
• bulging eye
• Graves' orbitopathy

Why it occurs

• Graves-Basedow disease (autoimmunity mediated by antibodies directed against the TSH receptor that cross-react in orbital fibroblasts, inducing glycosaminoglycan synthesis and cell recruitment)
• Hashimoto's thyroiditis (hyperthyroid phase or associated autoimmune orbitopathic variant)
• Inflammatory orbital pseudotumor (nonspecific and benign inflammatory process of the orbital tissues)
• Carotid-cavernous fistula (abnormal vascular communication that increases ophthalmic venous pressure and displaces the eyeball)
• Optic nerve sheath meningioma or orbital lymphoma (primary or secondary neoplasms that occupy space in the rigid orbital cavity)

Initial workup

Serum thyroid hormone profile (sensitive TSH, free T4 and free T3) to evaluate functional metabolic status; TSH receptor antibodies (TRAb) and thyroid-stimulating antibodies (TSI); High-resolution Magnetic Resonance (MRI) of the orbits with fat suppression and contrast (gadolinium) to examine the characteristic thickening of the belly of the extraocular muscles respecting the tendon insertions; and computerized visual campimetry to assess the functional viability of the optic nerve.

Standard management

• Methylprednisolone — weekly intravenous pulses of 500 mg during a protocolized regimen of 6 to 12 weeks in the moderate to severe active inflammatory phase to inhibit fibroblast activation
• Teprotumumab — monoclonal antibody directed against the insulin-like growth factor 1 receptor, indicated to reduce active proptosis and inflammation
• Selenium — oral supplementation of 100 mcg twice daily in mild forms of orbitopathy to limit the progression of oxidative stress damage
• Sodium hyaluronate eye drops 0.4% — ocular lubricant instilled every 2-4 hours to mitigate corneal desiccation secondary to lagophthalmos