The orbit has a close association with the cavernous sinus, which is prone to vascular disorders. Vascular abnormalities of the cavernous sinus have resulting orbital sequelae.
Carotid Cavernous Fistula (CCF)
CCF is an AV malformation between the carotid artery and the cavernous sinus. There are 2 types of CCF and an angiogram is used to provide a definitive diagnosis.
Direct CCF |
Indirect CCF |
|---|---|
High flow direct connection between internal carotid artery and cavernous sinus |
Low flow connection between the internal carotid artery and cavernous sinus via meningeal branches |
Typically caused by trauma leading to a fistula |
Typically occurs spontaneously in elderly hypertensive women |
Presents with ocular bruit, whooshing sound heard by patient, raised IOP and visual defects |
Presents with gradual onset irritated eye, increased IOP and corkscrew epibulbar vessels |
Management is with embolisation |
Most cases self resolve |
Remember that the internal carotid artery travels within the cavernous sinus.
Cavernous Sinus Thrombosis
The cavernous sinus is a venous blood sinus that is prone to thrombosis. Lots of important structures travel within this sinus.
Pathology
- A clot within the cavernous sinus (venous blood sinus)
- Typically caused by spreading infection.
Diagnostics
Presentation
- Acute onset headache, nausea, proptosis and diplopia
- Caused by compression of CN3, CN4 and CN6 as they traverse the sinus
Investigations
- MRI with MRI venogram is diagnostic.
CN6 is first affected because it travels within the sinus as opposed to CN3 and CN4 which travel within the walls of the sinus.
Management
- Antibiotics
- Steroids
- Thrombolytic medications
- Surgical drainage.
Orbital Varices
- Orbital varices are venous enlargements within the orbit
- Typically unilateral and medial.
- Key defining feature is intermittent proptosis
- Worsened by the Valsalva maneuver.
