Lid/Orbit
Carotid-Cavernous Fistula
Also known as: carotid cavernous fistula, CCF, dural fistula eye, dural arteriovenous fistula, pulsatile proptosis, corkscrew vessels, arterialised episcleral vessels, red eye with bruit
Filed as: Urgent
Source-cited from the record's own evidence list. Clinical content programme led by Dr Ankit Mathur, PhD, Grad Cert Ocu Thera, B.S. Optom. How the clinical content is governed
Clinical decision support only
Overview
An abnormal communication between the carotid circulation and the cavernous sinus, arterialising the orbital venous drainage. Two patterns matter clinically: the DIRECT (high-flow) fistula, typically after head trauma in a younger patient — abrupt pulsatile proptosis, chemosis, a bruit the patient may hear — and the INDIRECT (dural, low-flow) fistula, typically spontaneous in an older, often hypertensive patient, presenting as a chronically red, quietly congested eye that is repeatedly treated as conjunctivitis or cellulitis. The recognisable signature is arterialised, corkscrew episcleral vessels running to the limbus, raised IOP on the affected side, and orbital congestion WITHOUT fever or tenderness. Diagnosis is by imaging; definitive management is endovascular.
Recognition
Symptoms: what patients report
- Persistently red eye, often for weeks, unresponsive to topical treatment.
- A whooshing or pulsing noise in the head heard by the patient (subjective bruit) — direct fistulas especially.
- Double vision, from congestion or a sixth-nerve palsy (CN VI runs free in the sinus and fails first).
- Aching orbital fullness or pressure; blurred vision on the affected side.
- Direct fistulas: abrupt onset after head trauma; indirect fistulas: gradual onset in later life.
Signs: what the examination shows
- Arterialised, tortuous 'corkscrew' episcleral vessels running toward the limbus — the signature the benign mimics do not carry.
- Proptosis — pulsatile with a palpable thrill or audible bruit in high-flow fistulas.
- Chemosis and eyelid congestion without fever, warmth, or tenderness.
- Raised IOP on the affected side, from raised episcleral venous pressure.
- Restricted motility or an abduction deficit (CN VI palsy).
- Dilated retinal veins, intraretinal haemorrhages, or choroidal congestion in advanced venous stasis.
- Orbital auscultation may reveal a bruit in direct fistulas.
What OptoGuide™ covers for carotid-cavernous fistula
- Pattern reasoning: what this combination of findings points to, and its differentiators
- Don't-miss risks and escalation triggers
- Management tiers with linked Australian therapeutics
- Referral urgency, specialty, and letter drafting
Sources
- Eye Emergency Manual — NSW Agency for Clinical Innovation
- Carotid-cavernous fistula — StatPearls (NCBI Bookshelf)
- Clinical Reasoning: Proptosis, Headache, and Fever in a Healthy Young Woman. Orquera J, Godoy DA, Behrouz R, Rabinstein A, Di Napoli M. Neurology. 2016;86(16):e168-72.
- Cavernous sinus thrombosis: An insidious and dangerous “do‐not‐miss” diagnosis. Qu H, Li Y, Chen M, et al. Headache. 2021;61(7):1144-1149.
- Unilateral Proptosis, Redness, Diplopia, and Numbness in a Young Woman. Ali MH, Jones S, Moss HE. JAMA Ophthalmology. 2016;134(11):1325-1326.