Treatment Strategy Based on Experience of Treating Intracranial Infectious Aneurysms

Intracranial infectious aneurysms (IIAs) are a rare but unique subtype of potentially life-threatening vascular lesion. However, there is no widely accepted standard protocol for their management. We reviewed our treatment experiences of IIAs from 2001 to 2015 and proposed a treatment strategy for future use.

We retrospectively reviewed 25 patients with 33 IIAs. All patients had predisposing infectious disease for which the causative organism had been identified.

There were 12 patients with ruptured IIAs and 13 with unruptured IIAs. Of these patients, 17 (68%) had infective endocarditis, and viridans group streptococci (40%) were the most common causative organisms. All patients underwent antibiotic therapy, and 17 IIAs in 13 patients resolved with intravenous antibiotic therapy. However, 16 IIAs in 12 patients required neurosurgical treatment, including parent artery occlusion with glue or coils, endosaccular coiling, or microsurgery. The mean size of IIAs that responded to intravenous antibiotics (4.1 ± 2.2 mm) was smaller than that for IIAs with no response (7.5 ± 3.1 mm) (P = 0.01). Two patients had treatment-related complications: an acute cerebral infarction after parent artery occlusion and a rupture of the IIA during antibiotic therapy. There was no recurrence or mortality.

All patients with IIAs should undergo appropriate antibiotic therapy. In cases with unruptured IIA, patients can be managed using medical therapy with antibiotics alone for 4-6 weeks. However, neurosurgical treatment should be considered in cases of ruptured IIA or unruptured IIA that do not respond to antibiotic therapy.