Acute ischemic stroke after scuba diving in a patient with patent foramen ovale: a case of paradoxical embolism

Background. Ischemic stroke is an acute cerebrovascular event caused by impaired cerebral perfusion. Up to 40% of cases are cryptogenic. In younger patients, a patent foramen ovale (PFO) may enable paradoxical embolism, especially in settings associated with transient right-to-left shunting, such as scuba diving. Case report. A 47-year-old man developed acute focal neurological deficits immediately after scuba diving and performing Valsalva-like maneuvers. Non-contrast computed tomography showed early ischemic changes and a hyperdense right middle cerebral artery sign. Intravenous recombinant tissue plasminogen activator was administered within 180 minutes of symptom onset, resulting in complete neurological recovery. Magnetic resonance imaging at 24 hours showed no diffusion restriction, consistent with early reperfusion. Etiological evaluation revealed a hemodynamically significant PFO, atrial septal aneurysm, and a high-grade right-to-left shunt. The patient subsequently underwent successful percutaneous PFO closure. At 1-year follow-up, he remained asymptomatic without recurrent cerebrovascular events. Conclusion. In young patients with acute neurological deficits after diving, paradoxical embolism through a PFO should be considered. Comprehensive neurological and cardiological evaluation is essential for accurate etiological diagnosis and individualized secondary stroke prevention.