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Describe the cavernous sinus, superior orbital fissure and orbital apex syndromes.

Ophthalmology · 3rd Professional

Anatomy and the Three Syndromes

The cavernous sinus is a paired venous plexus on either side of the body of the sphenoid, and is unique in that an artery runs through a vein
Its contents, and their arrangement, explain every clinical sign:
Within the sinus, in the blood — the internal carotid artery with its surrounding sympathetic plexus, and the sixth (abducens) nerve

Syndrome	Structures involved and distinguishing feature
Superior orbital fissure syndrome	Cranial nerves III, IV, VI and V1, with the superior ophthalmic vein. Ophthalmoplegia, ptosis, a fixed pupil, and sensory loss over the forehead. NO visual loss and NO V2 involvement
Orbital apex syndrome	The above plus the optic nerve. The distinguishing feature is therefore visual loss with a relative afferent pupillary defect — and it is the presence of visual loss that separates apex from fissure
Cavernous sinus syndrome	III, IV, VI, V1 and V2, with the sympathetic plexus. The distinguishing features are V2 (cheek) sensory loss and a possible HORNER syndrome; visual acuity is preserved unless the lesion extends forward. Proptosis and chemosis are common

Causes and Management

Cavernous sinus thrombosis — septic, spreading from the dangerous area of the face, the paranasal sinuses, orbit or teeth, through valveless veins. Features: fever and systemic toxicity, proptosis, chemosis, ophthalmoplegia, and dilated tortuous retinal veins; and critically, it spreads to the other side within 24 to 48 hours through the intercavernous sinuses, which is essentially diagnostic. A medical emergency requiring high-dose intravenous antibiotics, anticoagulation and drainage of the source; mortality remains significant
Carotid-cavernous fistula — an abnormal communication between the carotid arterial system and the sinus:
Direct (high-flow) — traumatic, in a young patient, with a dramatic presentation: pulsatile proptosis, an audible bruit that the patient hears and the examiner can auscultate over the orbit and which diminishes on carotid compression, corkscrew arterialised episcleral vessels extending to the limbus, chemosis, raised intraocular pressure and ophthalmoplegia
Indirect (low-flow, dural) — spontaneous, in elderly hypertensive women; far more insidious, and frequently misdiagnosed as chronic conjunctivitis or thyroid eye disease for months. The clue is the corkscrew vessels and a raised pressure in a "red eye" that will not settle
Diagnosis is by CT or MR angiography showing a dilated superior ophthalmic vein, confirmed by digital subtraction angiography; treatment is by endovascular embolisation, and many low-flow fistulas close spontaneously

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