• Clinical science

Carotid-cavernous fistula (Caroticocavernous fistula…)


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)
  • Indirect (“low-flow” or “dural”) carotid-cavernous fistula



  • Direct carotid-cavernous fistula
    • Secondary to head trauma
    • Spontaneous
  • Indirect carotid-cavernous fistula



  • Arteriovenous fistula formation → high-pressure inflow of arterial blood into venous system → venous congestion
    • → Compression of cavernous sinus structures
      • Cranial nerves III, IV, and VI
      • 1st and 2nd branch of the trigeminal nerve (ophthalmic and maxillary nerves)
    • → Impaired venous drainage

Clinical features

Onset of symptoms may be abrupt or gradual, depending on whether the fistula is direct or indirect:

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.

  • CT/MR (with or without angiography) may show:
  • Ultrasound with transcranial Doppler: shows increased blood flow
  • Cerebral angiography
    • 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
  • Neurosurgery
    • Indicated if endovascular interventions fail or are not possible
    • Occlusion of the fistula via suturing or packing


last updated 12/05/2019
{{uncollapseSections(['8vaOb5', 'Eva8b5', 'Dva1X5', '9vaNX5', 'CvaqX5', 'yvadc5', 'zvarc5'])}}