Case of the Month
Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO
March 2023
Next Case of the Month Coming April 4...
Barrow Type D Caroticocavernous Fistula
- Background:
- Caroticocavernous fistulas (CCFs) represent arteriovenous fistulous communication between the carotid circulation and the cavernous sinus. They are broadly classified as direct and indirect, which in turn are representative of different underlying etiologies.
- Direct caroticocavernous fistulas are often secondary to trauma and more commonly encountered in young men. The presentation is acute and with rapid evolution of symptoms.
- In contrast, indirect caroticocavernous fistulas have a predilection for the postmenopausal female population, with an insidious chronology of symptoms.
- Clinical Presentation:
- In direct CCFs, patients present with posttraumatic proptosis, chemosis, subconjunctival hemorrhage, cranial nerve palsies, pulsatile tinnitus, and, at times, rapidly progressive vision loss.
- With indirect CCFs, patients often complain of diplopia insidious in onset and progressive in nature, headache, and features of raised intracranial pressure.
- Key Diagnostic Features:
- Oftentimes the characteristic telltale is the enlarged superior ophthalmic vein on CT/MR angiography along with bulging of the cavernous sinuses.
- Indirect radiologic cues are the features of orbital congestion in the form of fat stranding and bulky, inflamed extraocular muscles inferring venous congestion.
- Additionally, enhancement of the cavernous sinus with its attenuation parallel to the internal carotid artery/abnormal flow-related enhancement of the cavernous sinuses on TOF-MRA infer an underlying arterial communication.
- Barrow classification is based on the angiographic morphology of these fistulas, with type A representative of direct and types B, C, and D of indirect CCFs.
- Differential Diagnoses:
- Inflammatory pseudotumor
- Graves ophthalmopathy
- Orbital cellulitis
- Cavernous sinus thrombosis
- Treatment:
- Low-flow fistulas are usually managed conservatively with institution of carotid-jugular compression.
- High-flow fistulas are subjected to endovascular therapy with the aim of occluding the rent in ICA in the case of direct fistulas, while indirect CCFs are treated via transarterial embolization of meningeal feeders or transvenous embolization of the cavernous sinus.
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