- Clinical science
A carotid-cavernous fistula is an abnormal communication between a carotid artery and the cavernous sinus. It is most commonly caused by trauma. The fistula leads to a high-pressure inflow of arterial blood into the venous sinuses, resulting in compression and damage to adjacent structures. The main symptom is diplopia, caused by compression injury of the oculomotor nerves. Other common symptoms include pulsatile tinnitus, exophthalmos, and headache. Diagnosis is established based on typical findings on CT/MRI or angiography (e.g., enlarged cavernous sinus). The preferred treatment method is endovascular occlusion of the fistula with balloons or coils.
- Direct (“high-flow”) carotid-cavernous fistula (most common)
- Abnormal communication between the cavernous sinus and the intracavernous internal carotid artery
- Typically rapid onset of symptoms
- Indirect (“low-flow” or “dural”) carotid-cavernous fistula
Onset of symptoms may be abrupt or gradual, depending on whether the fistula is direct or indirect:
- Orbital pain
- Diplopia, blurry vision
- Pulsatile tinnitus (fistula bruit)
- Signs of congestion
If not treated swiftly, carotid-cavernous fistulas may result in cerebral hemorrhage/infarction, intracranial hypertension, vision loss or death!
- Initial studies help confirm the diagnosis.
- Gold standard for diagnosis (and treatment)
- Visualization of feeding vessels and blood flow
Embolization using balloons or coils
- Direct fistulas: transarterial approach
- Indirect fistulas: transvenous approach
- Indicated if endovascular interventions fail or are not possible
- Occlusion of the fistula via suturing or packing