Thyroid orbitopathy masked a carotid-cavernous fistula. Case report.

The case concerns a 73 year-old female with a diagnosis of hyperthyroidism of 8 months onset. Since then, she has suffered hyperaemia and ocular proptosis. Bilateral exophthalmos was observed in the physical examination, along with mild conjunctival hyperaemia in the right eye associated with dilated episcleral vessels. Computed tomography showed enlarged inferior rectus with no signs of ocular nerve or ophthalmic superior vein compression. In the orbital Doppler ultrasound scan, there was an arterialised flow over the superior ophthalmic vein, giving a possible diagnosis of cavernous carotid. Thyroid orbitopathy with a cavernous carotid fistula is an unusual combination in which the clinical signs of both pathologies can mask the complete diagnosis; thus it is important to be acquainted with both pathologies for their correct management and multidisciplinary treatment.