Meatal Anterior Inferior Cerebellar Artery Aneurysm with AICA-PICA Complex: Endovascular Coiling and Parent Artery Preservation

Secondary stroke prevention requires early initiation of antiplatelet; therefore, stroke mimics need to be ruled out particularly in circumstances when antiplatelet therapy can be of disastrous consequences. A 54-year-old female patient presented to the emergency department with symptoms of sudden-onset deviation of angle of mouth to the right side, left eye ptosis, and occipital headache for past 4-hour duration. Neurologic examination revealed right-sided gaze-dependent torsional nystagmus and left lower motor neuron facial weakness. An embolic posterior circulation stroke secondary to vertebral artery dissection was suspected. Diffusion-weighted imaging (DWI) did not show any acute infarcts, and careful review of susceptibility-weighted imaging (SWI) scans showed hemorrhage in the fourth ventricle. Subsequent digital subtraction angiography (DSA) was done, which showed left anterior inferior cerebellar artery (AICA) aneurysm involving its intrameatal segment with AICA-posterior inferior cerebellar artery (PICA) complex. Retrospective review of computed tomographic (CT) angiography images showed small aneurysm in the internal auditory meatus, which is difficult to discern secondary to adjacent bony structure and smaller size of the aneurysm. The patient underwent endovascular coiling of the aneurysm with preservation of the parent artery. Our experience concluded that these clinical features suggest remote subarachnoid hemorrhage secondary to the ruptured of AICA intrameatal segment aneurysm with left facial nerve paralysis and peripheral cochlear vestibular changes secondary to either compression (mechanical or pulsations of the aneurysm sac) or ischemia of vestibular apparatus. The neurointerventionist should consider the possibility of aneurysmal rupture, especially in cases of atypical location of hemorrhage and no signs of infarct on neuroimaging of posterior circulation stroke.