Download Carotid Cavernous Fistula

Carotid Cavernous Fistula
Laura S Gilmore, MD
Department of Ophthalmology
TTUHSC
February 13, 2004
Discussant: Kenn Freedman, MD
Case Presentation
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26yo AAM s/p MVA
CHI, L zygoma fracture
Consulted for proptotic, red OS
CT: proptosis OS. No basilar skull
fracture. no retrobulbar hematoma, no
superior ophthalmic vein enlargement,
no ocular muscle enlargement
Differential Diagnosis
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Cavernous Sinus Thrombosis
Retrobulbar Hematoma
Unrecognized intra-orbital FB, with
possible cellulitis
Carotid Cavernous Sinus Fistula
Tumor
Physical Exam
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General: sedated, intubated
Lids: edematous, margins intact
Pupils: 2.5mm->2mm, 7->NR
Conj: chemosis, OS>OD; SCH OS
IOP: 16, 28
Cornea 2+ edema OS, clear OD
+ gross proptosis OS
+ bruit OS on auscultation, no neck bruit
DFE: discs flat with sharp edges, vessels
normal, retina flat OU
MRI of CC Fistula
Carotid Cavernous Fistula
• Abnormal communication between
previously normal carotid artery
and cavernous sinus
• Characterized as:
-Direct vs. Indirect
-High vs. Low Flow
-Traumatic vs. Spontaneous
Types of CC Fistula
Mechanisms of CCSF
• Trauma
• Spontaneous causes:
– rupture of intracavernous aneurysms
– neurofibromatosis
– atherosclerotic disease
– collagen vascular disease
• Iatrogenic
Direct Carotid Cavernous Fistula
• Arterial blood passes directly through a
defect in the wall of intracavernous
portion of ICA
• Blood in vein becomes arterialized
• Venous pressure increases
• Arterial pressure and perfusion decreases
Signs of Direct CCSF
• Ptosis
• Very red, chemotic conj
• Increased IOP from increased episcleral
venous pressure
• Anterior segment ischemia in 20%
– Corneal edema, cell/flare, iris atrophy,
rubeosis, cataract
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Proptosis is pulsatile
Bruit and thrill
Muscle palsies
Visual loss
Etiologies of Direct CCSF
• From trauma in 75% of all cases
– Basal skull fracture tears ICA within
cavernous sinus
– Traumatic fistulae-high flow rates, sudden
and dramatic onset of symptoms
• Spontaneous rupture of aneurysm or
atherosclerotic artery in 25%
– Post-menopausal, hypertensive females
– Lower flow rates, less severe symptoms
Mechanisms of Traumatic CCSF
• direct injury from basilar skull fracture
• injury from torsion or stretching of the
carotid siphon upon impact
• impingement of the vessel on bony
prominences
Indirect Carotid Cavernous Fistula
• Fistulous connection is within the wall of the
cavernous sinus
• Tend to be low-flow
• Small meningeal arteries supplying dural wall
of cavernous sinus can rupture
spontaneously, while ICA itself remains intact
• Insidious onset, mild orbital congestion,
proptosis, low or no bruit
• Lesions may fluctuate, and may resolve
spontaneously
Clinical Presentation of CCSF
• Ophthalmic consequences of CCSF are
caused by compression and ischemia
related to increased venous pressure
and reduced arterial pressure
– flow reversal leads to engorged ophthalmic
veins causing proptosis, conjunctival
injection, chemosis.
– Patients complain of retro-orbital
headache, or a bruit. Facial pain with V1
and V2 involvement
Clinical Presentation of CCSF
• Other manifestations:
– congestion of the opposite orbit
– diplopia
– ptosis, mydriasis
– corneal ulceration
– loss of visual acuity
– transient neurological deficits
– subarachnoid hemorrhage
Radiological Evaluation of CCSF
• Angiography is the definitive diagnostic
examination
• CT and MRI may show
– Enlarged superior ophthalmic vein
– Enlarged muscles
– Enlarged cavernous sinus with a convex
shape to the lateral wall
Treatment of CCSF
• Most are not life-threatening
– Only involved eye is at risk typically
• Main indicators for treatment
– Glaucoma
– Diplopia
– Intolerable bruit or HA
– Severe proptosis causing exposure
keratopathy
– Spontaneous closure from thrombosis of
cavernous sinus is unlikely (as in trauma,
high-flow)
Treatment of CCS Fistulas
• 99% of treatment is done by
interventional neuroradiologists
– Intravascular approach-placement of
thrombogenic materials, eg coils
• Other therapies include:
– carotid artery ligation
– surgical exposure with clipping of the
fistula
Summary
• Direct CCSF usually results from trauma
• Patients typically present with proptosis,
conjunctival injection, and a bruit
• Angiography when pt stable
• Transarterial embolization