Isolated third nerve palsy with pupillary involvement resulting from carotid-cavernous sinus fistula: A case report

Rationale:Isolated third nerve palsy with pupillary involvement caused by a posterior drainage carotid-cavernous sinus fistula (CCF) is relatively rare. Diagnosis of a posterior drainage CCF can often be delayed due to its unapparent congestive signs.Patient concerns:Here, we present the case of a young male patient with right-sided CCF, who presented with right-side headache and partial third nerve palsy with pupillary involvement. The diagnosis was confirmed using time-of-flight magnetic resonance angiography (TOF-MRA) and digital subtraction angiography (DSA).Diagnoses:A right-sided CCF was detected, which was primarily supplied by the dural branch of the right middle meningeal artery and venous drainage into the right inferior petrosal sinus.Interventions:The patient was treated with transarterial coil embolization.Outcomes:At 2 months, ride-side headache was significantly improved and ptosis and limited extraocular muscle movement were partially resolved.Lessons:CCF might not always present with ocular congestion. Although uncommon, white-eye and painful third nerve palsy with pupillary involvement may be caused by a posterior drainage CCF.