Introduction: Infectious intracranial aneurysm (IIA, or mycotic aneurysm) is a cerebrovascular complication of infective endocarditis. We aimed to describe the clinical course of IIAs during antibiotic treatment.
Methods: We reviewed medical records of persons with infective endocarditis who underwent cerebral angiography at a single tertiary referral center from 2011-2016. Aneurysms were followed with subsequent angiography for bad outcome (growth, rupture or new IIA formation) or good outcome (regression or resolution) until endovascular therapy, aneurysm resolution, or end of observation.
Results: Of 618 patients included, 40 (6.5%) had 43 IIAs. Eighteen (42%) aneurysms underwent initial endovascular treatment. Twenty-five unruptured aneurysms were treated with antibiotics alone for a median 36 days (interquartile range (IQR) 9-57). Nine (36%) aneurysms had bad outcome (2 new IIA formation, 7 enlargement) at median 8 days, IQR 1-25. Angiography revealed good outcome in 7 (28%) patients (6 resolution, 1 regression) at median 36 days, IQR 16-49. Two patients had no IIA change after median 27 days, and both underwent endovascular treatment. Seven aneurysms had no angiographic reevaluations but no rupture during clinical follow-up for median 4 days, IQR 3-12. There were no aneurysmal ruptures during observation.
Conclusion: IIAs represent a dynamic disease. Only a quarter of IIAs resolve with antibiotics alone.