Incomplete Third Nerve Palsy Due to a Carotid-Cavernous Fistula.

Introduction: The approach to oculomotor nerve palsies involves the exclusion of compressive, infective, inflammatory, or ischemic lesions. Dural arteriovenous fistulae, including carotid-cavernous fistulae (CCF), are known causes of third nerve palsy. However, diagnosis can sometimes be delayed or missed due to the various clinical presentations. CCF remains a rare but treatable cause of third nerve palsy.

Case Report: A 63-year-old Chinese female presented to our unit with gradual onset horizontal diplopia. Clinical examination revealed a partial left oculomotor nerve palsy without congestive eye symptoms. A cerebral angiogram revealed a left indirect CCF supplied by the inferolateral trunk of the left internal carotid artery. She underwent successful transvenous embolization. She improved postprocedure and was discharged well on day 10 of her admission. She was reviewed at 2 months follow-up and had recovered completely.

Conclusion: Our case is a classic description of a CCF with posterior drainage into the inferior petrosal sinus. We hope this case and a review of the literature can serve as a reminder to clinicians of the varied presentations of CCF. We believe this case adds value to the clinicians in contributing to their diagnostic process and to our interventional colleagues in highlighting a case with a successful postembolization outcome.