View source for Carotid-cavernous fistula

==Background==
*Fistula between carotid and cavernous sinus 
*Majority arise from trauma
**Exact mechanism unclear/variable, may arise from small tear in internal carotid or branches due to basilar [[skull fracture]] (esp. through sphenoid), shear forces, or abrupt increases in intraluminal pressure when compressed due to neck flexion<ref>UpToDate</ref>
*May also occur spontaneously, due to aneurysms, thrombosis, or weakening in arterial wall 
**Risk factors include [[connective tissue disease]] e.g. Ehler's Danlos

==Clinical Features==
*Onset typically abrupt within hours to few days after initial insult, but may present weeks after trauma
*Symptoms due to arterialization of orbital veins
*Pulsating exophthalmos/[[proptosis]] 
*Raised [[intraocular pressure]]
*[[Eye pain]] (ocular and/or orbital), [[headache]]
*[[Red eye|Chemosis]]
*[[Diplopia]] or blurry vision
*[[Abducens nerve palsy|CN VI palsy]]
**Esotropia (eye moves inwards), [[diplopia]]
*[[Third nerve palsy|CNIII palsy]]
**Exotropia (eye moves laterally)
**Ptosis
**Pupillary dilation
*Bruit (over eye or head)

Possible complications include:
*Acute angle [[glaucoma]], [[vitreous hemorrhage]], [[retinal detachment]]
**Can lead to [[vision loss]]
*[[ICH]], [[SAH]] (if fistula drains into cortical veins)
*Severe [[epistaxis]]

==Differential Diagnosis==
{{Bilateral Red Eyes}}

==Evaluation==
*Conventional angio is gold standard, but can be seen on [[head CT|CT]]/CTA or [[brain MRI|MRI]]/MRA of head/orbits

==Management==
*5-10% close spontaneously<ref>Adams and Victor's Principles of Neurology, 10e</ref> remainder must be closed by interventional radiology (e.g. embolization) or surgically

==Disposition==


==See Also==
*[[Red eye]], [[eye pain]]
*[[Head trauma]]
*[[Cranial nerve palsies]]

==External Links==


==References==
<references/>
[[Category:Vascular]]