• Etiology
  • Cavernous sinus thrombosis (e.g., due to sinusitis and contiguous spread of infection)
  • Carotid-cavernous fistula
  • Cavernous sinus tumors
• Clinical features
  • Swelling of the conjunctiva
  • Proptosis
  • Signs of CN palsy due to compression (CN III, IV, V-1, V-2, and VI pass through the cavernous sinus)
    • Painful ophthalmoplegia: partial/complete paresis of oculomotor nerve (CN III), trochlear nerve (CN IV), and abducens nerve (CN VI)
    • Absent corneal reflex: paresis of the ophthalmic branch of the trigeminal nerve (V1)
    • Loss of upper facial and corneal sensation may occur due to damage to the trigeminal branches of V1 and V2 .
  • Horner syndrome