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11th July, 20212 min read

What is a carotid cavernous fistula?

Medical reviewer:Dr Ann Nainan
Author:Dr Adiele Hoffman
Last reviewed: 12/07/2021
Medically reviewed

All of Healthily's articles undergo medical safety checks to verify that the information is medically safe. View more details in our safety page, or read our editorial policy.

What is a carotid cavernous fistula?

A carotid cavernous fistula is an abnormal connection between a blood vessel in your neck, called the carotid artery, and a network of veins behind your eyes, called the cavernous sinus.

Your cavernous sinus normally drains blood from your eyes and face. But if you develop a carotid cavernous fistula, this blood flows the wrong way and fills up in your eyes – making them bulge and look red.

A carotid cavernous fistula can happen after a head injury or if you have high blood pressure, but sometimes there’s no clear cause.

What are the symptoms of a carotid cavernous fistula?

There are 2 main types of carotid cavernous fistula: direct or indirect. Direct carotid cavernous fistulas arise from a hole in a branch of your carotid artery that lies inside the cavernous sinus. Indirect fistulas are caused by an uneven connection between your carotid artery and cavernous sinus.

Depending on the type of fistula you have, your symptoms can come on quickly (over a fews days or weeks) or more gradually.

Symptoms of a carotid cavernous fistula include:

  • red eyes
  • bulging eyes
  • problems seeing or double vision
  • hearing the sound of blood flow around your eyes
  • feeling a pulse in your eyes
  • problems moving your eyes
  • eye or face pain, or headaches
  • nosebleeds
  • ringing in your ears

How is a carotid cavernous fistula treated?

Sometimes a carotid cavernous fistula will close off by itself and won’t need treatment. But most types will need a procedure or surgery to block them off – sometimes using a balloon or a coil. Occasionally you’ll need emergency treatment to stop any bleeding, and protect your eyesight.

You may also need some treatment for your eyes, like artificial tears (lubricating drops) or eye drops to lower the pressure in your eyes.

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