Man presents with proptosis, chemosis and red eye after motorcycle crash
A 49-year-old man was transferred to the University of New Mexico Health Sciences Center after a helmeted motorcycle crash. He suffered a skull base fracture, multiple facial fractures including bilateral medial and inferior orbital wall fractures, bilateral orbital roof fractures and a left lateral orbital wall fracture. He presented with multiple brain hemorrhages. He was intubated and admitted to the neurosurgical intensive care unit. Ophthalmology was consulted for the orbital fractures.
On examination, the patient’s vision could not be elicited due to intubation. His pupils were equally round and reactive to light. There was no relative afferent pupillary defect. Severe periorbital ecchymosis and edema were present in both eyes. Extraocular movements were limited due to soft tissue swelling. Mild proptosis and lid lag were present in both eyes, and the findings were more pronounced in the right eye. There was no resistance to retropulsion. The IOP was soft by palpation. Slit lamp exam showed bilateral conjunctival chemosis and exposure keratopathy in both eyes. The anterior chambers were deep, and there was no hyphema. The lens was clear in both eyes. Dilated fundus examination was deferred due to hourly neuro checks. Given the proptosis and corneal exposure, intensive lubrication and corneal protection were recommended.
During his hospital course, the patient developed severe prolapsing conjunctival chemosis with conjunctival and episcleral venous congestion. He also developed worsening proptosis of the right eye (Figure 1). The right pupil became dilated and nonreactive to light with a reverse afferent pupillary defect. IOP was 45 mm Hg in the right eye and 18 mm Hg in the left eye. Visual acuity decreased to no light perception in the right eye. The cornea of the right eye showed a central epithelial defect and subepithelial fibrosis inferiorly. No fundus details could be appreciated due to the exposure keratopathy.
Images: Semela LB, Boisvert C
What is your diagnosis?
Proptosis, chemosis, episcleral venous congestion
Given that trauma is the etiology of the patient’s signs and symptoms, the differential diagnosis becomes quite narrow. In trauma associated with craniofacial fractures, a carotid cavernous sinus fistula, retrobulbar hematoma, superior orbital fissure syndrome and orbital apex syndrome have to be considered. Given the patient’s clinical presentation of prolapsing chemosis and episcleral injection with worsening proptosis in the setting of head trauma, a traumatic carotid-cavernous sinus fistula (CCF) was suspected. A cavernous sinus thrombosis can present with the same signs but is most commonly caused by bacterial infection of the cavernous sinus.
The patient underwent neuroimaging, and the studies were reviewed. A CT angiography study demonstrated enlargement of the right superior ophthalmic vein, enlarged extraocular muscles and enhancement of the right cavernous sinus consistent with a carotid cavernous sinus fistula (Figure 2). The patient underwent an emergent transarterial coiling procedure by interventional neuroradiology to embolize the fistula.
Traumatic carotid cavernous sinus fistulas are rare but potentially lethal vascular anomalies in the skull base seen after craniomaxillofacial trauma. They represent an abnormal communication between the carotid artery and the cavernous sinus. The fistulas were angiographically classified by Barrow and colleagues. Direct fistulas have an abnormal communication between the internal carotid artery and the cavernous sinus (Barrow type A fistulas). Indirect fistulas have communications between the small meningeal branches of the internal, external, or both internal and external carotid artery and the cavernous sinus (Barrow type B, C and D fistulas), which are also called cavernous sinus-dural fistulas. The direct fistulas are mainly high-flow shunts, which usually have a traumatic origin, and only a few resolve without therapy. The majority of dural shunts are idiopathic and appear spontaneously. The incidence of a CCF as a result of craniomaxillofacial trauma is less than 0.2%, although CCF is the most common posttraumatic intracranial vascular anomaly.
The majority of the signs and symptoms, as well as possible sequelae, of CCF are the result of shunting of blood between a high-flow and low-flow system. The venous congestion occurring within and around the cavernous sinuses causes a state of hypertension in the surrounding vascular tree. The orbits, whose venous drainage travels to the cavernous sinuses through the superior and inferior ophthalmic veins, are the first structures to manifest the symptoms of this reversed blood flow. Common signs of CCF include proptosis, temporal/orbital bruit, chemosis, extraocular palsy, pulsating exophthalmos, elevated IOP, anterior segment ischemia, papilledema, optic nerve atrophy and trigeminal nerve involvement. The classic triad of the more commonly occurring anterior CCF consists of proptosis, bruit and chemosis. The most common cause for visual loss is secondary glaucoma due to elevated episcleral venous pressure, as was the case in our patient. Other causes include choroidal detachment, diplopia, proptosis with corneal exposure, macular edema, venous stasis retinopathy, or retinal or optic nerve ischemia.
The diagnosis of carotid cavernous sinus fistula is based on clinical findings and must be confirmed by CT scan or angiography. Angiography can reveal the precise location and size of a CCF. CT with contrast is also useful because it can depict any bony fractures or spicules around the cavernous sinus as well as outline engorged superior ophthalmic veins, a common radiographic finding in CCF. MRI and MRA have been used in demonstrating reversal of blood flow with the cavernous sinus and superior ophthalmic veins. Angiographic studies in our patient showed a high-flow CCF caused by the skull base fracture through the right petrous internal carotid artery canal (Figure 3).
Treatment of direct cavernous sinus fistulas consists of embolization of the fistula. Different modalities such as detachable balloon or coiling methods are available. This procedure is usually performed by an interventional neuroradiologist via transarterial or transvenous access of the fistula. Our patient underwent coiling embolization of the CCF via a transfemoral access.
After successful coiling embolization of the cavernous sinus fistula, IOP normalized immediately in the affected eye. The chemosis, conjunctival and episcleral vessel dilation regressed slowly. The patient’s vision, however, did not recover (Figure 4).
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- Linda Brenner Semela, MD, and Chantal Boisvert, MD, can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.
- Edited by Priti Batta, MD, and Namrata Nandakumar, MD. Drs. Batta and Nandakumar can be reached at New England Eye Center, Tufts University School of Medicine, 750 Washington St., Box 450, Boston, MA 02111; 617-636-4219; fax: 617-636-4866; website: www.neec.com.