Clinical Reasoning: A 60-Year-Old Woman With Fever, Headache, Diplopia, and Unilateral Periorbital Swelling.

Evaluating delayed vascular complications after a focal cranial infection can be diagnostically challenging. In this case, a 60-year-old woman with approximately 1 month of recurrent gingival swelling and pain later developed fever and headache, followed by horizontal diplopia and progressive unilateral periorbital swelling. Examination showed a left abduction deficit and conjunctival chemosis. Cerebral angiography obtained during evaluation demonstrated severe narrowing of the cavernous segment of the internal carotid artery. Although the patient improved clinically after antimicrobial therapy, routine follow-up imaging 1 year later revealed a new vascular lesion at the site of the prior arterial abnormality. This case highlights the importance of interval neurovascular follow-up imaging when cavernous internal carotid artery abnormalities are identified during the initial presentation of febrile ophthalmoplegia.