eMedicine Specialties > Ophthalmology > Orbit

Fistula, Carotid Cavernous

Ingrid U Scott, MD, MPH, Professor, Department of Ophthalmology and Public Health Sciences, Penn State College of Medicine

Updated: Feb 17, 2010

Introduction

Background

Carotid-cavernous sinus fistula is an abnormal communication between the internal or external carotid arteries and the cavernous sinus. These lesions may be classified based on the following: etiology (traumatic vs spontaneous), velocity of blood flow (high vs low), and anatomy (direct vs dural, or internal carotid vs external carotid).

Pathophysiology

Carotid-cavernous sinus fistulae occur because of traumatic or spontaneous rents in the walls of the intracavernous internal carotid artery or its branches. This results in short-circuiting of the arterial blood into the venous system of the cavernous sinuses.^{[1 ]}

Direct carotid-cavernous sinus fistulae, which represent 70-90% of all carotid-cavernous sinus fistulae in most series, are characterized by a direct connection between the intracavernous segment of the internal carotid artery and the cavernous sinus. These fistulae usually have high rates of arterial blood flow and most commonly are caused by a single traumatic tear in the arterial wall.

Dural carotid-cavernous sinus fistulae are characterized by a communication between the cavernous sinus and one or more meningeal branches of the internal carotid artery, external carotid artery, or both. These fistulae usually have low rates of arterial blood flow and almost always produce symptoms and signs spontaneously, without any antecedent trauma or manipulation. The lesions may represent congenital arteriovenous malformations, which develop spontaneously or in association with atherosclerosis, systemic hypertension, collagen vascular disease, pregnancy, and during or after childbirth.

Frequency

United States

Rare

International

Rare

Mortality/Morbidity

Nearly all patients with a direct carotid-cavernous sinus fistula experience progressive ocular complications if the fistula is left untreated. Increasing proptosis, conjunctival chemosis, and visual loss occur over months to years, with central retinal vein occlusion and secondary glaucoma representing the most severe ocular complications.

Several investigators have reported severe epistaxis and intracerebral hemorrhage, potentially fatal, in patients with traumatic carotid-cavernous sinus fistulae. Subarachnoid hemorrhage also may complicate the course of a traumatic carotid-cavernous sinus fistula. A 3% incidence of spontaneous intracerebral hemorrhage caused by carotid-cavernous sinus fistulae has been reported.

Visual loss, although less frequent than in patients with direct carotid-cavernous sinus fistulae, occurs in 20-30% of patients with dural carotid-cavernous sinus fistulae and may be due to secondary ischemic optic neuropathy, chorioretinal dysfunction, including central retinal vein occlusion, or uncontrolled glaucoma.

Sex

• While direct carotid-cavernous sinus fistulae generally are associated with trauma or surgical manipulation, dural carotid-sinus fistulae occur more commonly in middle-aged to elderly women.

Age

• Traumatic carotid-cavernous sinus fistulae occur more commonly in young individuals.
• Dural carotid-cavernous sinus fistulae usually occur in middle-aged to elderly women but may produce symptoms at any age, including infancy.

Clinical

History

• Elicit history of trauma, recent childbirth, or surgical manipulation.
• Elicit history of atherosclerosis, systemic hypertension, collagen vascular disease, pseudoxanthoma elasticum, connective tissue diseases (eg, Ehlers-Danlos syndrome), or pregnancy.
• Patients may present with the following ocular complaints:
  • Red eye
  • Diplopia
  • Bruit (buzzing or swishing sounds)
  • Decreased vision
  • Bulging eye
  • Facial pain in the distribution of the first (and rarely the second) division of the trigeminal nerve

Physical

• Ophthalmologic examination findings consistent with carotid-cavernous sinus fistula include the following:
  • Proptosis
  • Eyelid edema
  • Ocular pulsations (visible and/or palpable)
  • Pulsating exophthalmos
  • Ocular bruit
  • Conjunctival arterialization and chemosis
  • Exposure keratopathy
  • Dilation of retinal veins
  • Optic disc swelling
  • Intraretinal hemorrhage
  • Vitreous hemorrhage
  • Proliferative retinopathy
  • Central retinal vein occlusion
  • Elevated intraocular pressure
  • Neovascular glaucoma
  • Angle-closure glaucoma (In rare cases, increased orbital venous pressure leads to iris and choroid congestion and forward displacement of the iris-lens diaphragm.)

Causes

• Approximately 25% of carotid-cavernous sinus fistulae occur spontaneously, especially in middle-aged to elderly women, and may be associated with atherosclerosis, systemic hypertension, collagen vascular disease, pregnancy, connective tissue disorders (eg, Ehlers-Danlos syndrome), and minor trauma.
• Cerebral trauma accounts for approximately 75% of carotid-cavernous sinus fistulae, with motor vehicle accidents, fights, and falls representing the most common settings. The injuries may be penetrating or nonpenetrating and may be associated with basal or facial skull fracture.
• Iatrogenic fistulae have been reported following trans-sphenoidal pituitary surgery, endarterectomy, ethmoidal sinus surgery, and percutaneous gasserian and retro-gasserian procedures.

Differential Diagnoses

Thyroid Ophthalmopathy

Other Problems to Be Considered

Orbital pseudotumor
Any spheno-orbital mass lesion

Workup

Imaging Studies

• Direct carotid-cavernous sinus fistulae: Computed tomography (CT) scan, magnetic resonance imaging (MRI), and orbital echography often help to confirm the diagnosis, demonstrating extraocular muscle enlargement, dilation of one or both superior ophthalmic veins, and enlargement of the affected cavernous sinus.^{[2 ]}
• Dural carotid-cavernous sinus fistulae: CT scan, MRI, and orbital echography may help to confirm the diagnosis.
• All carotid-cavernous sinus fistulae
  • The definitive diagnostic test is cerebral arteriography with selective catheterization of the internal and external carotid arteries on both sides, so that all arterial contributions to the fistulae can be visualized.
  • Intra-arterial subtraction angiography is generally the preferred technique.

Other Tests

• Tonometry (preferably with a pneumotonometer) usually demonstrates greater pulse amplitude on the side of the lesion.

Treatment

Medical Care

• Exposure keratopathy may be treated with ocular lubricants, and, in severe cases, a tarsorrhaphy may be needed.
• Glaucoma may require treatment with aqueous suppressants and hyperosmotic agents.
• Laser peripheral iridectomy may be performed to eliminate the contribution of pupillary block, and cycloplegic agents may be used to encourage a posterior shift of the iris-lens diaphragm.
• Laser iridoplasty or goniosynechialysis may help further in opening the angle.
• Proliferative retinopathy and neovascular glaucoma may require panretinal photocoagulation.

Surgical Care

• The optimal treatment of a direct carotid-cavernous sinus fistula is closure of the abnormal arteriovenous communication with preservation of internal carotid artery patency. Techniques for achieving this result include surgical repair of the damaged portion of the intracavernous internal carotid artery, electrothrombosis, embolization, or balloon occlusion of the fistula.^{[3,4,5,6 ]}
• Dural carotid-cavernous sinus fistulae may close spontaneously, but, for those lesions causing progressive or unacceptable symptoms and signs, standard embolization or endovascular balloon occlusion is generally performed. If these techniques are unsuccessful, direct surgery on the cavernous sinus may be considered. In cases where anatomy makes standard intravascular approach impossible, the superior ophthalmic vein can be cannulated and a balloon or coil threaded into the area of a direct communication.

Consultations

• Neurosurgical consultation for management of the carotid-cavernous fistula

Medication

The goals of pharmacotherapy are to reduce morbidity and to prevent complications. Medications used to decrease aqueous production include beta-blockers, carbonic anhydrase inhibitors (topical or oral), and alpha2-agonists.

Beta-adrenergic blockers

Decrease intraocular pressure (IOP) by reducing the aqueous production.

Timolol 0.25% or 0.5% (Timoptic, Timoptic XE, Blocadren)

May reduce elevated and normal IOP, with or without glaucoma by reducing production of aqueous humor or by outflow.

Dosing

Adult

1 gtt bid
Timoptic XE: 1 gtt qd

Pediatric

Administer as in adults

Interactions

May cause bradycardia and asystole when used in combination with systemic beta-blockers (may cause additive effects)

Contraindications

Documented hypersensitivity; bronchial asthma; sinus bradycardia; second-degree and third-degree AV block; severe chronic obstructive pulmonary disease; overt cardiac failure; cardiogenic shock

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Product may have sulfites, which may cause allergic-type reactions in susceptible patients; may exacerbate or precipitate heart block, asthma, chronic obstructive pulmonary disease, mental changes (especially in elderly persons)

Levobunolol 0.25% or 0.5% (AKBeta, Betagan)

Nonselective beta-adrenergic blocking agent that lowers IOP by reducing aqueous humor production and possibly increases outflow of aqueous humor.

Dosing

Adult

1 gtt bid

Pediatric

Not established

Interactions

May cause bradycardia and asystole when used in combination with systemic beta-blockers (may cause additive effects)

Contraindications

Documented hypersensitivity; bronchial asthma; severe chronic obstructive pulmonary disease; sinus bradycardia; second-degree and third-degree AV block; overt cardiac failure; cardiogenic shock

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

May have sulfites, which may cause allergic-type reactions in certain susceptible persons

Metipranolol 0.3% (OptiPranolol)

Beta-adrenergic blocker that has little or no intrinsic sympathomimetic effects and membrane stabilizing activity. Has little local anesthetic activity. Reduces IOP by reducing production of aqueous humor.

Dosing

Adult

1 gtt bid

Pediatric

Not established

Interactions

May cause bradycardia and asystole when used in combination with systemic beta-blockers (may cause additive effects)

Contraindications

Documented hypersensitivity; sinus tachycardia; cardiac failure; cardiogenic shock; second- and third-degree AV block

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in diabetes mellitus, bradycardia, asthma, cardiac failure, and AV block

Carteolol 1.0% (Ocupress)

Blocks beta1- and beta2-receptors and has mild intrinsic sympathomimetic effects.

Dosing

Adult

1 gtt bid

Pediatric

Not established

Interactions

May cause bradycardia and asystole when used in combination with systemic beta-blockers (may cause additive effects)

Contraindications

Documented hypersensitivity; congestive heart failure; asthma; cardiac conduction defects; breastfeeding

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Product may have sulfites, which may cause allergic-type reactions in certain susceptible persons

Betaxolol (Betoptic, Kerlone)

Selectively blocks beta1-adrenergic receptors with little or no effect on beta2-receptors. Reduces IOP by reducing production of aqueous humor.

Dosing

Adult

1 gtt bid

Pediatric

Not established

Interactions

May have additive systemic effects if patient is already on systemic beta-blockers

Contraindications

Documented hypersensitivity; bronchial asthma; severe chronic obstructive pulmonary disease; sinus bradycardia; second-degree and third-degree AV block; overt cardiac failure; cardiogenic shock

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Product may have sulfites, which may cause hypersensitivity reactions in susceptible persons

Carbonic anhydrase inhibitors

By slowing the formation of bicarbonate ions with subsequent reduction in sodium and fluid transport, it may inhibit CA in the ciliary processes of the eye. This effect decreases aqueous humor secretion, reducing IOP.

Dorzolamide 2% (Trusopt)

Used concomitantly with other topical ophthalmic drug products to lower IOP. If more than one ophthalmic drug is being used, administer the drugs at least 10 min apart. Reversibly inhibits carbonic anhydrase, reducing hydrogen ion secretion at renal tubule and increases renal excretion of sodium, potassium bicarbonate, and water to decrease production of aqueous humor.

Dosing

Adult

1 gtt tid

Pediatric

Not established

Interactions

Coadministration with high-dose salicylate therapy may increase toxicity; may have additive systemic effects if patient is already on oral CA inhibitors

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Local ocular adverse effects, primarily conjunctivitis and lid reactions, may occur with chronic administration of dorzolamide (discontinue therapy and evaluate patient before restarting therapy)

Brinzolamide 1% (Azopt)

Catalyzes reversible reaction involving hydration of carbon dioxide and dehydration of carbonic acid. May use concomitantly with other topical ophthalmic drug products to lower IOP. If more than one topical ophthalmic drug is being used, administer drugs at least 10 min apart.

Dosing

Adult

1 gtt tid

Pediatric

Not established

Interactions

May have additive systemic effects if patient is already on oral CA inhibitors

Contraindications

Documented hypersensitivity

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Local ocular adverse effects, primarily conjunctivitis and lid reactions may occur with chronic administration (discontinue therapy and evaluate patient before restarting therapy)

Acetazolamide (Diamox, Diamox Sequels)

Inhibits enzyme carbonic anhydrase, reducing rate of aqueous humor formation, which, in turn, reduces IOP. Used for adjunctive treatment of chronic simple (open-angle) glaucoma and secondary glaucoma and preoperatively in acute angle-closure glaucoma when delay of surgery desired to lower IOP.

Dosing

Adult

125 mg or 250 mg PO bid/qid or 5-10 mg/kg q6-8h Acetazolamide sequel: 500 mg PO bid

Pediatric

5 mg/kg PO q6h

Interactions

Can decrease therapeutic levels of lithium and alter excretion of drugs (amphetamines, quinidine, phenobarbital, salicylates) by alkalinizing urine

Contraindications

Documented hypersensitivity; hepatic disease; severe renal disease; adrenocortical insufficiency; severe pulmonary obstruction

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Patients with impaired hepatic function may go into coma; may cause substantial increase in blood glucose in some diabetic patients

Methazolamide (Neptazane)

Reduces aqueous humor formation by inhibiting enzyme carbonic anhydrase, which results in decreased IOP.

Dosing

Adult

25 or 50 mg PO bid/tid

Pediatric

Not established

Interactions

May increase toxicity of salicylate, digoxin; coadministration with other diuretics may induce hypokalemia; decreases effects of lithium and alter excretion of other drugs by alkalinizing urine

Contraindications

Documented hypersensitivity; renal impairment

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

Caution in respiratory acidosis and diabetes mellitus; impairs mental alertness and/or physical coordination; hematuria, glycosuria, polyuria, hepatic insufficiency, bone marrow suppression, thrombocytopenia/purpura, agranulocytosis, urticaria, pruritus, and rash may occur

Alpha-agonists

The exact mechanism of ocular antihypertensive action is not established but appears to be a reduction of aqueous humor production.

Brimonidine 0.2% (Alphagan)

Selective alpha2 receptor that reduces aqueous humor formation and increases uveoscleral outflow.

Dosing

Adult

1 gtt tid before and after laser or surgery, short term

Pediatric

Administer as in adults

Interactions

Coadministration with topical beta-blockers may further decrease IOP; tricyclic antidepressants may decrease effects of brimonidine; CNS depressants, such as barbiturates, opiates, and sedatives, may potentiate effects of brimonidine

Contraindications

Documented hypersensitivity; patients receiving MAOIs

Precautions

Pregnancy

B - Fetal risk not confirmed in studies in humans but has been shown in some studies in animals

Precautions

May exacerbate or precipitate ocular irritation, topical sensitivity, vasovagal attack, and optic nerve ischemia in patients with advanced glaucomatous optic neuropathy

Apraclonidine 0.5% or 1% (Iopidine)

Reduces elevated, as well as normal, IOP whether or not accompanied by glaucoma. A relatively selective alpha-adrenergic agonist that does not have significant local anesthetic activity. Has minimal cardiovascular effects.

Dosing

Adult

1 gtt tid before and after laser or surgery, short term

Pediatric

Administer as in adults

Interactions

Documented hypersensitivity; patients on MAOIs or have taken them in the past 14 d

Contraindications

Not established

Precautions

Pregnancy

C - Fetal risk revealed in studies in animals but not established or not studied in humans; may use if benefits outweigh risk to fetus

Precautions

May exacerbate or precipitate ocular irritation, topical sensitivity, vasovagal attack, and optic nerve ischemia in patients with advanced glaucomatous optic neuropathy

Follow-up

Further Outpatient Care

• Further outpatient care includes periodic monitoring of the condition.

Inpatient & Outpatient Medications

• See Medication.

Prognosis

• Although direct carotid-cavernous sinus fistulae rarely reopen after closure using a detachable balloon technique, it is not unusual for dural carotid-cavernous sinus fistulae to recanalize or form new abnormal vessels after embolization. The ocular pulse amplitude should be checked postoperatively in all patients, preferably using a pneumotonometer.
• Once a fistula is closed, symptoms and signs usually begin to improve within hours to days. The rate and extent of improvement are associated with the severity of the signs and the length of time the fistula was present.
  • Preexisting ocular bruit, ocular pulsations, and thrill generally disappear immediately after the surgery.
  • Eyelid engorgement, conjunctival chemosis, dilated conjunctival vessels, stasis retinopathy, disc swelling, and elevated intraocular pressure generally return to normal within weeks to months.
  • Most patients with dural carotid-cavernous sinus fistulae are healthy within 6 months after treatment, but patients with direct carotid-cavernous sinus fistulae may not experience complete resolution of proptosis, ophthalmoparesis, and visual loss.

Miscellaneous

Medicolegal Pitfalls

• Prompt recognition allows earlier treatment possibilities.

References

1. Karaman E, Isildak H, Haciyev Y, Kaytaz A, Enver O. Carotid-cavernous fistula after functional endoscopic sinus surgery. J Craniofac Surg. Mar 2009;20(2):556-8. [Medline].

2. Yu JS, Lei T, Chen JC, He Y, Chen J, Li L. Diagnosis and endovascular treatment of spontaneous direct carotid-cavernous fistula. Chin Med J (Engl). Aug 20 2008;121(16):1558-62. [Medline].

3. Kirsch M, Henkes H, Liebig T, et al. Endovascular management of dural carotid-cavernous sinus fistulas in 141 patients. Neuroradiology. Jul 2006;48(7):486-90. [Medline].

4. Yoon WK, Kim YW, Kim SR, Park IS, Kim SD, Baik MW. Transarterial coil embolization of a carotid-cavernous fistula which occurred during stent angioplasty. Acta Neurochir (Wien). May 5 2009;[Medline].

5. Wang C, Xie X, You C, Zhang C, Cheng M, He M, et al. Placement of Covered Stents for the Treatment of Direct Carotid Cavernous Fistulas. AJNR Am J Neuroradiol. Apr 2 2009;[Medline].

6. Bing F, Albrieux M, Vinh Moreau-Gaudry V, Vasdev A. Cavernous sinus fistula treated through the transvenous approach: Report of four cases. J Neuroradiol. Feb 27 2009;[Medline].

7. de Keizer R. Carotid-cavernous and orbital arteriovenous fistulas: ocular features, diagnostic and hemodynamic considerations in relation to visual impairment and morbidity. Orbit. Jun 2003;22(2):121-42. [Medline].

8. Debrun GM, Vinuela F, Fox AJ, et al. Indications for treatment and classification of 132 carotid-cavernous fistulas. Neurosurgery. Feb 1988;22(2):285-9. [Medline].

9. Higginbotham EJ. Glaucoma associated with increased episcleral venous pressure. In: Albert DM, Jakobiec FA, eds. Principles and Practice of Ophthalmology. 2nd ed. 2000: 2781-92.

10. Ishijima K, Kashiwagi K, Nakano K, et al. Ocular manifestations and prognosis of secondary glaucoma in patients with carotid-cavernous fistula. Jpn J Ophthalmol. Nov-Dec 2003;47(6):603-8. [Medline].

11. Keltner JL, Satterfield D, Dublin AB, Lee BC. Dural and carotid cavernous sinus fistulas. Diagnosis, management, and complications. Ophthalmology. Dec 1987;94(12):1585-600. [Medline].

12. Miller NR. Carotid-cavernous sinus fistulas. In: Miller NR, ed. Walsh and Hoyt's Clinical Neuro-Ophthalmology. 4th ed. Baltimore, Md: Williams;1991: 2165-209.

13. Rai AT, Sivak-Callcott JA, Larzo C, Marano GD. Direct carotid cavernous fistula in infancy: presentation and treatment. AJNR Am J Neuroradiol. Jun-Jul 2004;25(6):1083-5. [Medline].

14. Troost BT, Glaser JS, Morris PP. Aneurysms, arteriovenous communications, and related vascular malformations. In: Glaser, ed. Neuro-ophthalmology. 3rd ed. Philadelphia, Pa: Lippincott Williams & Wilkins;1999: 589-628.

Keywords

carotid cavernous fistula, carotid-cavernous sinus fistula, carotid artery, cavernous sinus

Contributor Information and Disclosures

Author

Ingrid U Scott, MD, MPH, Professor, Department of Ophthalmology and Public Health Sciences, Penn State College of Medicine
Ingrid U Scott, MD, MPH is a member of the following medical societies: American Academy of Ophthalmology, American Medical Association, American Society of Cataract and Refractive Surgery, American Society of Retina Specialists, Association for Research in Vision and Ophthalmology, Macula Society, Phi Beta Kappa, and Retina Society
Disclosure: Nothing to disclose.

Medical Editor

Stephen D Plager, MD, FACS, Chief, Department of Ophthalmology, Dominican Hospital; Assistant Clinical Professor, Department of Ophthalmology, Stanford University Hospital
Stephen D Plager, MD, FACS is a member of the following medical societies: American College of Surgeons, American Medical Association, American Society of Cataract and Refractive Surgery, and California Medical Association
Disclosure: Nothing to disclose.

Pharmacy Editor

Simon K Law, MD, PharmD, Assistant Professor of Ophthalmology, Jules Stein Eye Institute; Chief of Section of Ophthalmology Surgical Services, Department of Veterans Affairs Healthcare Center, West Los Angeles
Simon K Law, MD, PharmD is a member of the following medical societies: American Academy of Ophthalmology, American Glaucoma Society, and Association for Research in Vision and Ophthalmology
Disclosure: Nothing to disclose.

Managing Editor

Mark T Duffy, MD, PhD, Consulting Staff, Division of Oculoplastic, Orbito-facial, Lacrimal and Reconstructive Surgery, Green Bay Eye Clinic, BayCare Clinic; Medical Director, Advanced Cosmetic Solutions, A BayCare Clinic
Mark T Duffy, MD, PhD is a member of the following medical societies: American Academy of Ophthalmology, American Medical Association, American Society of Ophthalmic Plastic and Reconstructive Surgery, Sigma Xi, and Society for Neuroscience
Disclosure: Allergan - Botox Cosmetic Consulting fee Consulting; Quest medical - lacrimal balloons Honoraria Speaking and teaching; Ortho-Neutrogenia Consulting fee Consulting

CME Editor

Lance L Brown, OD, MD, Ophthalmologist, Affiliated With Freeman Hospital and St John's Hospital, Regional Eye Center, Joplin, Missouri
Disclosure: Nothing to disclose.

Chief Editor

Hampton Roy Sr, MD, Associate Clinical Professor, Department of Ophthalmology, University of Arkansas for Medical Sciences
Hampton Roy Sr, MD is a member of the following medical societies: American Academy of Ophthalmology, American College of Surgeons, and Pan-American Association of Ophthalmology
Disclosure: Nothing to disclose.

Related eMedicine topics
Carotid-Cavernous Fistula (from Radiology)
Cavernous Sinus Syndromes
Cavernous Sinus Thrombosis
Arteriovenous Fistulas
Hemangioma, Cavernous

Guidelines
ACR Appropriateness Criteria Orbits, Vision, and Visual Loss
ACR Appropriateness Criteria Cerebrovascular Disease

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