Fact-sheet: Carotid-cavernous sinus fistula


Updated on 06/23/2020 at 10:05 AM

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Definition

Carotid-cavernous sinus fistula is an abnormal arteriovenous shunt between the carotid system and the cavernous sinus.

There are two types of fistulas:

-> Direct carotid-cavernous sinus fistulas (70 to 90% of carotid-cavernous sinus fistulas) occur in the setting of trauma or after neurosurgical intervention.

-> Dural arteriovenous fistulas of the cavernous sinus. Unlike direct fistulas, dural fistulas are low-flow. They generally develop on pre-existing lesions: congenital (vascular malformations, collagen vascular disorders) or acquired (systemic arterial hypertension, atheromatous lesions, diabetes, thrombophlebitis, pregnancy, delivery, postpartum).

Clinical features

History taking:

  • Headaches
  • Trigeminal neuralgia (V1 ++)

On inspection:

  • Pulsatile exophthalmos
  • Bruit perceived by the patient
  • Dilation of the episcleral veins with chemosis, eyelid edema

On auscultation:

  • Decreased visual acuity
  • Complete ophthalmoplegia

Clinical examination reveals complete ophthalmoplegia.

Eyelid edema, chemosis, ptosis, conjunctival redness with "caput medusae" dilation of the episcleral veins, pulsatile exophthalmos with thrill, exposure keratitis, ocular hypertonia (related to increased pressure in the episcleral veins), retinal vein dilation, intraretinal or intravitreal hemorrhages, and papilledema.

CT

- Enlargement of the cavernous sinus
- Dilatation of the superior ophthalmic vein
- +/- dilatation of cortical veins

- Exophthalmos

- After injection, all ocular structures show abnormal enhancement (extraocular muscles, optic nerve sheaths, ocular coats…)

MRI

Orbital MRI

On T1:

  • dilatation of the superior ophthalmic vein (hyperintense if thrombosed, hypointense if rapid flow)
  • enlargement of the ipsilateral cavernous sinus

On T2: better visualization of the cavernous sinus

Vascular intervention

X-Ray Angiography: precise lesion work-up and assessment of the circle of Willis.
Endovascular treatment

Differential diagnosis

Spontaneous dural fistulas of the cavernous sinus