วันพุธที่ 18 กุมภาพันธ์ พ.ศ. 2569

Carotid-Cavernous Fistula (CCF)

Carotid-Cavernous Fistula (CCF)

INTRODUCTION

Carotid-cavernous fistula (CCF) คือ acquired vascular shunt ระหว่าง carotid arterial system กับ cavernous sinus ทำให้เกิด arterialization ของ venous drainage ใน orbit และ cavernous sinus นำไปสู่ neuro-ophthalmologic morbidity ที่สำคัญ รวมถึง vision loss, cranial neuropathy และ intracranial hemorrhage
การตัดสินใจรักษาขึ้นกับ

  • ชนิดของ fistula (flow + angioarchitecture)
  • อาการและความรุนแรง
  • ความเสี่ยงต่อ visual และ neurologic morbidity

CLASSIFICATION

1. ตาม hemodynamics

High-flow (Direct CCF)

  • Direct communication: intracavernous ICA → cavernous sinus
  • มักอาการรุนแรงและเกิดเร็ว

Low-flow (Indirect / Dural CCF)

  • Shunt ผ่าน dural branches ของ ICA/ECA → cavernous sinus
  • อาการค่อยเป็นค่อยไป

2. Barrow classification (สำคัญทางคลินิก)

Type

ลักษณะ

Flow

Source

A

Direct ICA → cavernous sinus

High-flow

ICA tear (มัก trauma)

B

Dural branches ของ ICA

Low-flow

Indirect

C

Dural branches ของ ECA

Low-flow

Indirect

D

ICA + ECA dural branches

Low-flow

Indirect

EPIDEMIOLOGY (Key points)

  • พบได้ทุกอายุ
  • Direct CCF: พบบ่อยในชายอายุน้อย (trauma-related)
  • Dural CCF: พบบ่อยในหญิงอายุ >50 ปี
  • พบได้ ~4% ของผู้ป่วย basilar skull fracture

ETIOLOGY

1. Direct (High-flow) – MOST COMMON = Trauma

  • Severe head trauma / skull fracture (พบบ่อยสุด)
  • Penetrating injury
  • Iatrogenic (endovascular, transsphenoidal surgery, sinus surgery)
  • Ruptured cavernous ICA aneurysm
  • Connective tissue disorders
    • Ehlers-Danlos syndrome
    • Fibromuscular dysplasia
    • Pseudoxanthoma elasticum

Note: อาจเกิด delayed days–weeks หลัง trauma

2. Indirect (Dural CCF)

Pathophysiology:

  • Preexisting microscopic dural AV shunts +
  • Venous hypertension / venous thrombosis → recruitment of shunts

Risk factors:

  • Hypertension
  • Hypercoagulable state (pregnancy/postpartum)
  • Age-related vascular changes
  • Rarely trauma

CLINICAL PRESENTATION

1. Direct High-flow CCF (classic & fulminant)

Onset: acute, rapidly progressive

Classic triad (important exam point)

  • Pulsatile proptosis
  • Conjunctival chemosis/injection
  • Ocular bruit (subjective or audible)

Common symptoms/signs

  • Diplopia (50–85%)
  • Proptosis (72–87%)
  • Headache (53–75%)
  • Ocular/orbital pain
  • Blurred vision
  • Chemosis + corkscrew vessels
  • Elevated IOP → secondary glaucoma

Cranial neuropathy

  • CN VI palsy (most common)
  • CN III, IV involvement
  • CN V sensory loss (cavernous sinus involvement)

Severe complications

  • Central retinal vein obstruction
  • Exposure keratopathy → corneal ulcer
  • Central retinal artery occlusion (rare)
  • Intracranial hemorrhage (≈5%, esp. cortical venous drainage)
  • Life-threatening epistaxis (rare)

2. Indirect (Dural) CCF – Subtle & chronic

Typical patient: older woman >50 ปี

Pattern depends on venous drainage

A. Anterior drainage (most common)

  • Red eye (misdiagnosed as conjunctivitis)
  • Chemosis
  • Proptosis
  • Corkscrew episcleral vessels
  • Abducens palsy → diplopia
  • Vision loss (~1/3)

B. Posterior drainage (white-eyed painful diplopia)

  • Minimal proptosis/chemosis
  • Painful ophthalmoplegia
  • CN III palsy (common)

C. Cortical venous drainage (HIGH RISK)

  • Neurologic deficits
  • Venous infarction
  • Intracranial hemorrhage

RED FLAGS (ต้องสงสัย CCF สูง)

  • Pulsatile tinnitus/bruit + red eye
  • Proptosis + diplopia หลัง head trauma
  • Corkscrew conjunctival vessels
  • Elevated IOP + orbital congestion
  • Painful ophthalmoplegia
  • White-eyed diplopia (posterior draining dural CCF)

DIFFERENTIAL DIAGNOSIS

Important mimickers:

  • Cavernous sinus thrombosis
  • Orbital cellulitis
  • Tolosa-Hunt syndrome
  • Intracranial tumor (most common mass lesion)
  • Carotid aneurysm/dissection
  • Diabetic cranial neuropathy
  • Giant cell arteritis
  • Ophthalmoplegic migraine

DIAGNOSTIC IMAGING (Clinical approach)

Gold standard

Digital Subtraction Angiography (DSA)

  • Confirm diagnosis
  • Define feeders + drainage pattern
  • Plan endovascular treatment
  • Detect cortical venous drainage (hemorrhage risk)

Indication:

  • Diagnosis uncertain
  • Candidate for intervention
  • Suspicion despite negative CT/MRI

Initial Imaging (practical ER/clinic workflow)

CT / CTA

Findings:

  • Dilated superior ophthalmic vein (SOV) (key sign)
  • Cavernous sinus enlargement
  • Proptosis
  • EOM enlargement
  • Skull fracture (trauma)

CTA: high sensitivity (บาง study > MRA สำหรับ proximal cavernous sinus)

MRI / MRA

  • Flow void in cavernous sinus (specific clue)
  • Dilated SOV
  • Orbital congestion
  • 3D TOF MRA sensitivity ~83%, specificity ~100%

TCD

  • ↑ flow velocity + ↓ pulsatility index (carotid siphon)
  • Useful for follow-up, not definitive diagnosis

NATURAL HISTORY & INDICATION FOR TREATMENT

Direct CCF

  • Rarely close spontaneously
  • Usually require closure
  • ~20% need emergent treatment

Emergent indications

  • Rapid vision loss
  • Severe ↑ IOP
  • Intracranial hemorrhage
  • Progressive neurologic deficit
  • Severe proptosis/ophthalmoplegia

Indirect (Dural) CCF

  • Spontaneous closure 20–60%
  • Conservative observation possible (mild symptoms)

Definite indications for closure

  • Cortical venous drainage
  • Progressive vision loss
  • Severe diplopia / ophthalmoplegia
  • Refractory ocular hypertension
  • Neurologic symptoms

TREATMENT (Stepwise, modern practice)

1. Endovascular therapy (FIRST-LINE)

Preferred modality for almost all CCF

A. Transarterial embolization

Best for:

  • Direct CCF (Type A)

Materials:

  • Detachable balloons
  • Coils
  • Liquid embolic agents
  • Stent-assisted techniques

Goal: close fistula while preserving ICA

Success: 55–99%

Complications:

  • ICA occlusion
  • Stroke
  • Cranial nerve palsy

B. Transvenous embolization

Best for:

  • Indirect (dural) CCF (Type B–D)

Access routes:

  • Inferior petrosal sinus (common)
  • Superior ophthalmic vein
  • Facial vein
  • Direct surgical access (rare)

Cure rate: 70–90%
Complication: 2–5%

2. Manual carotid compression (selected cases only)

For mild dural CCF
Protocol: ~30 sec compression several times/day for 4–6 weeks

Contraindications:

  • Vision loss
  • Neurologic symptoms
  • Cortical venous drainage
  • Carotid disease
  • High-flow CCF

3. Surgery

Indications:

  • Failed endovascular therapy
  • Complex anatomy

Risk: high morbidity + ICA sacrifice possible

4. Stereotactic radiosurgery

Indications:

  • Non-urgent dural CCF
  • Not amenable to endovascular/surgery
    Limitation: delayed effect (months–years)

OPHTHALMOLOGIC MANAGEMENT (Adjunct)

  • Lubrication for exposure keratopathy
  • Topical IOP-lowering agents (β-blocker, etc.)
  • Acetazolamide (adjunct)
  • Eye patch / prism for diplopia

Key principle:
Treat the CCF first before ocular surgery

PROGNOSIS

After successful closure:

  • Chemosis / proptosis / IOP → improve within days
  • Cranial nerve palsy → weeks (บางราย persistent)
  • Vision recovery depends on duration & severity
  • Recurrence: ~<10% (higher in dural CCF)

CLINICAL PEARLS (High-yield for emergency & neuro-ophthalmology)

  • Red eye + bruit + proptosis = think CCF until proven otherwise
  • Post-traumatic diplopia with pulsatile symptoms → urgent CTA/DSA
  • “White-eyed painful diplopia” ในผู้สูงอายุ = suspect posterior draining dural CCF
  • Dilated superior ophthalmic vein on CT/MRI = key radiologic clue
  • Cortical venous drainage = highest risk for hemorrhage → treat aggressively
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