Air embolism is an uncommon but potentially catastrophic event due to air entry into the vasculature resulting in ischemic strokes. Cerebral air embolism (CAE) can be a complication of medical procedures, although non-iatrogenic sources have rarely been reported. Nonetheless, it is a life-threatening emergency with high mortality and disability. We present a patient with an acute infarct due to a CAE during air travel. 

Case Report: 

 A 67-year-old woman presents with two episodes of impaired consciousness during flights while in Europe. Both happened shortly after ascent. Her symptoms quickly resolved after an emergent landing on her first trip. During the second trip, however, symptoms recurred, and she remained unconscious. She was evaluated at a local hospital where a head computed tomography (CT) showed multiple cortical air locules, predominantly in the right hemisphere, consistent with cerebral air embolism. CT chest revealed a large left bulla with surrounding neovascularization, likely the cause of the embolism. A magnetic resonance imaging (MRI) brain confirmed numerous subacute infarcts across multiple vascular territories and diffuse white matter signal abnormality, consistent with the sequela of cerebral air embolism. She was transported to the US by sea for further management at a tertiary hospital, where she had successful resection of left lung bulla. She was subsequently discharged home with very mild left ataxia. 

Non-iatrogenic CAE is an extremely rare cause of ischemic stroke. Previously described cases relate to barometric pressure changes: during diving and ascent. We describe a patient presenting with CAE secondary to pulmonary shunt from a large lung bulla under barometric pressure changes during aircraft ascent. While literature suggests CAE as a life-threatening emergency with poor prognosis, this patient had an excellent outcome after surgical resection of the lung bulla, indicating possibly different outcomes between non-iatrogenic vs. iatrogenic CAE.