Cerebral Air Embolism with Pneumomediastinum Resulting from Emesis: A Case Report.

Cerebral air embolism (CAE) is a rare cause of stroke. Most cerebral air emboli are caused by iatrogenic factors, such as invasive cardiac and pulmonary procedures. Here, we report an unusual case of CAE not related to any medical intervention. An 87-year-old woman became unresponsive after vomiting. A computed tomography (CT) scan of the head 6 hours after the onset of the vomiting revealed multiple air emboli, mainly in the watershed area between the right anterior and middle cerebral arteries. Magnetic resonance imaging with T2* gradient echo showed the air emboli as granular hypointensities. Diffusion-weighted imaging revealed an area of hyperintensity along the cortical region of the right frontal lobe. Head CT scans showed that the size and number of the air emboli rapidly decreased on day 2 and disappeared on day 9. We also performed a chest CT and found pneumomediastinum, which gradually improved over the clinical course. We also found pulmonary fibrosis and bronchiectasis, suggesting an underlying pulmonary vulnerability. In this case, the emesis may have been a trigger for the CAE, which was followed by pneumomediastinum. This case suggests that CAE can occur in a noniatrogenic situation, especially in a patient with pulmonary vulnerability.