Carotid Cavernous Fistulas

The neurosurgeons and interventional neuroradiologists at Houston Methodist diagnose and treat many kinds of cerebrovascular conditions, including carotid-cavernous sinus fistulas.

A carotid-cavernous sinus fistula (CCF) is an abnormal connection between a carotid artery (the arteries that run up your neck to your brain) and the cavernous sinus (complex collection of veins) located behind your eyes. If one of these arteries tears or develops a hole near the veins in the cavernous sinus area, a fistula (channel or shunt) develops, which allows blood flow from the artery to the vein. 

There are two types of carotid-cavernous sinus fistulas.

• Direct CCFs usually result from a torn carotid artery. This type is often caused by head trauma; between 70 and 90 percent of direct CCFs are caused by injury to the base of the skull (basal skull fractures).
• Indirect CCFs occur spontaneously and can be caused by a connective tissue disorder. Although less common, they can also be caused by ruptured aneurysms or atherosclerotic (hardened) arteries. Indirect CCFs occur more often in postmenopausal women who have high blood pressure.

Symptoms of Carotid-Cavernous Sinus Fistulas
A CCF can raise the pressure in the cavernous sinus and affect nearby nerves that control eye movements and some sensations in parts of your head and face. It can also affect the veins that drain the eyes. CCFs are one of the causes of “red eye” and other visual problems, including vision loss, if not diagnosed and treated. Many people who have carotid-cavernous fistulas consult their eye doctors first because of eye or vision symptoms, but other symptoms may also occur:

• Double vision
• Eye pain or pressure
• Conjunctivitis (pink eye) symptoms
• A red or bulging eye (proptosis) that may pulse
• Hearing a rumbling, buzzing or swishing sound (called a bruit)

Diagnosis of Carotid-Cavernous Sinus Fistulas
Diagnosing a carotid-cavernous fistula begins with a thorough exam, including an eye exam. Your neurologist may order imaging scans to get a look at your eye, nearby blood vessels and cavernous sinus area:

• Ultrasound
• Computerized tomography (CT) scan
• Magnetic resonance imaging (MRI)

Treatment Options for Carotid-Cavernous Sinus Fistulas
Rarely can a direct carotid-cavernous sinus fistula heal on its own without any treatment. When a CCF causes severe symptoms, or symptoms get worse over time, it may need to be treated with surgery.

Endovascular embolization
Endovascular embolization is the most common treatment for CCF. In this procedure, a neurosurgeon or interventional neuroradiologist inserts a tiny catheter into an artery in your groin, and then guides it up to the fistula. Platinum coils or other materials can be inserted through the catheter and may be used to block the abnormal blood flow between the artery and vein.

Medication
No drug can cure a CCF, but if it causes eye symptoms, drugs may be prescribed to lubricate the eye or lower eye pressure.

Recovery and Rehabilitation for Carotid-Cavernous Sinus Fistulas
Treatment of direct CCF treatment usually results in relatively rapid and permanent resolution; many people notice an improvement in their symptoms within a few hours or days. Most people recover within six months. However, not everyone recovers completely and sometimes indirect CCFs can recur and will need to be treated again.