The patient had been treated for 1 month for presumed preseptal
Catherine A. Cox
Jordana F. Goren
A 68-year-old woman was transferred to Tufts Medical Center with
worsening right-sided periorbital swelling and diplopia. She had previously
been followed by an outside ophthalmologist for 1 month for presumed preseptal
The patients symptoms began 1 month before presentation as
intermittent right-sided periorbital swelling and ptosis. She had been treated
with various antibiotics for presumed cellulitis, including her current
antibiotics of cefuroxime and metronidazole. Additional symptoms over the
course of 1 month included an intermittent, subjective right-sided bruit as
well as intermittent diplopia. The patient denied any history of trauma,
headache, fever, chills or sinus pain. On the day of transfer to Tufts Medical
Center, the patient presented to an outside hospital for worsening periorbital
swelling and diplopia. She was found to have an IOP of 40 mm Hg in her right
eye; therefore, she was started on oral acetazolamide plus brimonidine,
latanoprost and timolol eye drops. A head CT was also obtained. The patient had
no ocular history. Her medical history was significant for hypertension and
On examination, the patients visual acuity was 20/40 in the right
eye and 20/20 in the left eye. Her right pupil was fixed at 5 mm, and her left
pupil was reactive with no reverse afferent pupillary defect. IOP was 30 mm Hg
in the right eye and 10 mm Hg in the left eye. Extraocular movements were
restricted in the right eye and full in the left eye. Confrontation visual
fields were full in both eyes. The patient was able to identify all Ishihara
color plates with both eyes. Exophthalmometry showed 6 mm of right eye
proptosis. Slit lamp biomicroscopy of the right eye revealed a swollen and
ptotic lid (Figure 1), 360° of chemosis with prominent corkscrew vessels
inferiorly (Figure 2), as well as corneal Descemet folds. The rest of the
anterior segment and dilated fundus examinations were within normal limits in
Significant right-sided periorbital edema and erythema. Ptosis and anisocoria
are seen as well.
Images: Vuong LN, Hedges TR
|Figure 2. Right eye
chemosis with inferior dilated corkscrew vessels.
What is your diagnosis?
Given the patients presentation, our first concern was for a
carotid-cavernous fistula or dural shunt. Orbital cellulitis, including a
subperiosteal abscess or cavernous sinus thrombosis, was also a possibility.
Inflammatory processes including thyroid ophthalmopathy, idiopathic orbital
pseudotumor, sarcoidosis or vasculitis were also considered. Finally, neoplasm
was unlikely but still in our differential.
Review of the outside hospital CT scan revealed a dilated right superior
ophthalmic vein and an enlarged cavernous sinus (Figure 3). These findings were
consistent with a right-sided carotid-cavernous fistula. An MRI with angiogram
confirmed our diagnosis by revealing branches of the internal carotid artery in
communication with the cavernous sinus. No venous thrombosis of the cavernous
sinus was present.
Figure 3. A dilated right superior ophthalmic
vein (left, arrow) and enlarged cavernous sinus (right) are present on
Carotid-cavernous fistulas can be classified as one of two types:
high-flow with direct communication between the internal carotid artery and
cavernous sinus; or low-flow with indirect communication via arterial branches
between the internal carotid artery and cavernous sinus. The latter is
sometimes also referred to as a dural shunt. The Barrows classification further
sorts dural shunt/carotid-cavernous fistulas by the specific internal carotid
artery branches involved.
High-flow carotid-cavernous fistulas are commonly diagnosed in young men
after significant head trauma. These types of fistulas may also be secondary to
aneurysm rupture or collagen vascular disease (eg, fibromuscular dysplasia,
Ehlers-Danlos or pseudoxanthoma elasticum), or they can be idiopathic.
Conversely, dural shunts are more frequently diagnosed in older women with
microscopic communications between dural arteries and venous sinuses. Dural
shunts are also more common in patients with chronic hypertension.
Symptoms associated with high-flow carotid-cavernous fistulas include
audible bruits, headaches, blurred vision, diplopia, ocular/orbital pain,
proptosis, chemosis, injection and/or ophthalmoplegia. In some cases, critical
findings may include venous stasis retinopathy, exposure keratopathy, glaucoma
and/or central retinal artery occlusion. Dural shunts may present similarly,
but findings are typically less severe.
The gold standard for diagnosing a carotid-cavernous fistula is digital
subtraction angiography. Nonetheless, CT and MRI imaging are often the first
tests to be obtained due to their relative availability. Although CT and MRI
may assist in diagnosis, they do not provide the detail of angiography.
Transcranial Doppler may also be obtained in order to examine flow patterns
within a diagnosed fistula.
Treatment options vary depending on either the type of fistula or
patient symptomatology. There is spontaneous closure of 20% to 60% of dural
shunts; thus treatment options tend to be conservative for these patients. If
significant visual changes are present, intervention is advised. Possible
interventions include embolization with a balloon, platinum coil, polyvinyl
alcohol particulates or liquid adhesive. More invasive procedures include
packing of the cavernous sinus, as well as suturing, clipping or sealing the
fistula with glue or fascia. Ligation of the internal carotid artery has been
reported, but this carries a highly variable success rate of 30% to 100%.
Finally, stereotactic radiosurgery may be performed, although response to
treatment is often quite delayed.
Our patient was admitted to neurosurgery, continued on IOP-lowering
medications and scheduled for surgery. Before surgery, her right eye vision
worsened from 20/40 to 20/200, and ocular motility became even further
restricted. At this time, she was noted to be in angle closure with complete
shallowing of her right eye anterior chamber. Ultrasound biomicroscopy showed a
ciliary-choroidal effusion with anterior rotation of the ciliary body (Figure
4). The patient subsequently underwent an emergent embolization/coiling
procedure with the neurosurgical team. By postoperative day 4, her diplopia had
resolved, and she was noted to have improved visual acuity, extraocular
motility and deepening of the anterior chamber in her right eye. One month
after treatment, the patients right eye visual acuity was 20/40,
extraocular movements were full, exophthalmometry showed no proptosis, IOP was
within normal limits on one aqueous suppressant eye drop, and no chemosis or
episcleral vessels were present.
Ciliary-choroidal effusion with anterior rotation of the ciliary body and
shallowing of the anterior chamber vessels.
Carotid-cavernous fistulas may be misdiagnosed as preseptal cellulitis,
allergic conjunctivitis or infectious conjunctivitis. A dural
shunt/carotid-cavernous fistula should be considered when cellulitis does not
respond to appropriate antibiotic treatment and worsening of vision occurs
accompanied by proptosis, chemosis, dilated episcleral vessels and/or
ophthalmoplegia. Although angiography is the gold standard for diagnosing high-
and low-flow fistulas, CT and MRI scans may help with the diagnosis if superior
ophthalmic venous dilation is present. Although many dural shunts close
spontaneously, patients with vision-threatening symptoms should be referred for
emergent surgical intervention.
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eds. Ophthalmology. 3rd ed. Philadelphia: Elsevier;
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- Talks SJ, Salmon JF, Elston JS, Bron AJ. Cavernous-dural fistula
with secondary angle-closure glaucoma. Am J Ophthalmol.
- Laurel N. Vuong, MD, and Thomas R. Hedges III, MD, can be reached
at New England Eye Center, Tufts University School of Medicine, 800 Washington
St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website:
- Edited by Catherine A. Cox, MD, and Jordana F. Goren, MD, MS. Drs.
Cox and Goren can be reached at New England Eye Center, Tufts University School
of Medicine, 800 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax:
617-636-4866; website: www.neec.com.