NEWS & EVENTS
Retinal Review, Issue 17
CASE NUMBER 17
A 54 year old woman was referred for ocular redness, pain and double vision. Past medical history is significant for hypertension. Past ocular history is significant for mild myopia. She was in her usual state of health until two weeks ago when she noted redness and discomfort in her right eye. She went to her internist and was given vigamox eye drops QID. The redness did not improve and she went to her OD. He noted ocular inflammation and added topical steroid QID. She returned a week later with increasing redness and discomfort. Intraocular pressure was measured at 30 in the right eye. Topical alphagan was added to the regimen due to a presumed steroid response. Several days later she noted the onset of binocular diplopia and was referred to us for evaluation and management.
On examination, visual acuity measured OD: 20/40 and OS: 20/20. IOP’s were OD: 37 and OS: 15. There was extensive vascular congestion of the right conjunctiva and episclera. Ocular rotations were reduced in the right eye in all aspects of gaze. There was 4.5mm of proptosis of the right eye. Visual field testing was full OU. Dilated examination revealed mild optic nerve swelling OD and a normal optic nerve OS.
The above findings were compatible with an acute orbital process. The differential diagnosis for acute orbital disease includes disthyroid orbitopathy, orbital inflammation (orbital pseudotumor), orbital mass, infection (orbital cellulitis), and vascular lesion. The patient was scheduled for an urgent MRI. The results are shown below (different patient but similar findings):
The scans both demonstrate an enlarged superior ophthalmic vein. The patient was diagnosed with a dural/sinus fistula. As opposed to a carotid/cavernous fistula which is a high flow state due to a communication between the internal carotid artery and the cavernous sinus, a dural/sinus fistula is a low flow communication. Meningeal branches from the carotid artery communicate with the cavernous sinus. Because of the increased venous pressure, there is dilation of the superior ophthalmic vein and orbital congestion. A dural/sinus fistula can be caused by atherosclerosis or can be idiopathic. A carotid/cavernous fistula is often caused by trauma. Treatment of a dural/sinus fistula is either observation or embolization. Her medical team elected careful observation to see if the malformation closes on its own. If not she will require embolization.