A case of delayed-diagnosis direct carotid-cavernous fistula beginning with pulsatile tinnitus

Introduction: A carotid-cavernous fistula (CCF) is an abnormal arteriovenous connection between the internal or external carotid artery system and the cavernous sinus. It can present with pulsatile tinnitus, diplopia, proptosis, conjunctival hyperemia, and chemosis. Nonspecific initial complaints and normal findings on initial noninvasive imaging can lead to diagnostic delay. This report presents a direct CCF that initially presented with pulsatile tinnitus alone and in which neuro-ophthalmological findings developed during follow-up.Case: A forty-six-year-old man was evaluated for right-sided pulsatile tinnitus that began about five months after he underwent rhinoplasty with osteotomy in July 2025. At his first presentation, cranial MRI, MR venography, and CT performed at another center showed no pathology. About six months later, he was re-evaluated at our clinic after developing diplopia, proptosis of the right eye, conjunctival hyperemia, and chemosis. Findings suggestive of a vascular pathology on orbital MRI led to digital subtraction angiography (DSA). DSA showed a direct carotid-cavernous fistula between the right cavernous internal carotid artery and the cavernous sinus. Deep venous drainage was restricted because of narrowing of the inferior petrosal sinuses; venous flow was directed to the superior and inferior ophthalmic veins, the sphenoparietal sinus, the superficial middle cerebral vein, and cortical veins, with prominence and tortuosity of these structures. For endovascular treatment, two covered stents were placed across the fistula segment and balloon angioplasty was performed. Control angiography showed that flow through the fistula had been eliminated. After the procedure, the pulsatile tinnitus disappeared completely, the diplopia improved markedly, and the proptosis nearly resolved (Figure 1).Discussion/Conclusion: Carotid-cavernous fistula should be kept in mind in the differential diagnosis, especially in patients in whom progressive ocular and cranial nerve findings develop after pulsatile tinnitus. Normal initial MRI, MRV, or CT does not exclude CCF. When clinical suspicion persists, DSA is critical not only for a definitive diagnosis but also for demonstrating the venous drainage pattern and planning treatment. In our patient, although there was a temporal relationship between the rhinoplasty and symptom onset, no finding demonstrated direct vascular injury, so a definite causal relationship could not be established. This case emphasizes the importance of clinical follow-up and advanced vascular imaging in CCF with an atypical onset.Keywords: