gms | German Medical Science

Objective: Infectious (mycotic) intracranial aneurysms (IIA) is a very rare complication of systemic infections, commonly related to bacterial endocarditis. True incidence of IIA is still unknown, since IIA were reported to represent 0.5-6.5% of all cases with intracranial aneurysms. Based on our institutional aneurysm database, we aimed at analyzing epidemiologic and clinical characteristics of IIA.

Methods: We retrospectively collected IIA cases from our aneurysm database containing 2852 patients with intracranial aneurysms consecutively treated at our institution between 2003 and 2018. Demographic, radiographic and clinical characteristics of patients with IIA were analyzed and compared with those of non-IIA cases from the database.

Results: Based on radiographic aneurysm characteristics, 26 cases were initially suspected to have IIA. However, IIA were confirmed only in 14 patients (<0.5% of the whole cohort). IIA cases were younger (46.8 vs 54.9 years for non-IIA cases hereinafter, p=0.0671), contained equal proportions of females (50% vs 68.5%, p=0.2331) and were overrepresented with SAH (71.4% vs 47.2%, p=0.1237). Regarding radiographic features, true IIA were more frequently fusiform (53.8% vs 2.5%, p<0.0001), located on distal branches (64.3% vs 4.3%, p<0.0001), presented mostly as single intracranial aneurysms (92.9% vs 65.4%, p=0.0612), and, in cases of ruptured aneurysms, with intracerebral hemorrhage (70% vs 29.8%, p=0.0108). SAH due to IIA was characterized with higher in-hospital mortality (40% vs 17.7%, p=0.0904). Among IIA patients who survived the initial hemorrhage of SAH, there were more cases with a favorable outcome (mRS≤3, 83.3% vs 70.4%, p=0.6763).

Conclusion: A true IIA is an exceptionally rare angiographic finding with certain radiographic patterns. SAH in cases of IIA is characterized with a considerable mortality. However, patients with IIA surviving SAH have good chances for a favorable functional outcome.