Recurrent vertebrobasilar strokes and transient-ischemic attacks with challenging workup: Case report

Detecting the stroke etiology in young patients can be challenging. Among others, determining causality between ischemic stroke and patent foramen ovale (PFO) remains a complicated task for stroke neurologists, given the relatively high prevalence of PFOs. Thorough diagnostic workup to identify incidental vascular risk factors and rare embolic sources is crucial to avoid premature PFO closure suggesting successful secondary stroke prevention. In this paper, we report on a 38-year-old patient with recurrent vertebrobasilar territory, especially right posterior inferior cerebellar artery (PICA) territory strokes. After the initial suspicion of a left vertebral artery (VA) dissection was not confirmed by ultrasound and magnetic resonance imaging (MRI) and other major risk factors were excluded, a PFO was detected and closed. Successful PFO closure was confirmed by transesophageal echocardiography, yet recurrent transient-ischemic attacks and vertebrobasilar strokes, especially during nighttime and in the early morning, occurred despite various antiplatelet and antithrombotic regimes and a persistent right-to-left shunt was detected by bubble transcranial Doppler. Finally, MRI after another vertebrobasilar infarction detected a transient left VA occlusion that finally led to the diagnosis of a left VA pseudoaneurysm from an incident emboligenic dissection in the atlas segment. This pseudoaneurysm together with an anatomical variant of the right PICA originating with the right anterior inferior cerebellar artery from the basilar artery finally explained the recurrent ischemic events of the patient. After successful treatment with coil occlusion, the patient suffered no further stroke and recovered completely. In summary, stroke in the young remains a diagnostic challenge. The incidental finding of a PFO should not deter from thorough stroke workup and the follow-up of these patients including PFO closure verification should be performed under the guidance of vascular neurologists.