Abstract Introduction Congenital cystic lung lesions occur in the general population at a rate of 1 in 10,000-30,000 live births, but many are asymptomatic and are only detected on incidental imaging. This case demonstrates a rare complication of a previously undetected bronchogenic cyst during air travel. Case Summary The patient was a 62-year-old female, never smoker, with past medical history notable only for hypothyroidism. An hour into her fourth commercial flight of life, she began complaining of a headache. Later in the flight, her husband noticed that she was unresponsive with roving eye movements, which progressed to seizure-like activity on landing. She was transferred by EMS to the ED, intubated for airway protection, and admitted to ICU. Imaging on admission was notable for a 12cm bullous lesion in the right lung containing hemorrhagic fluid; no other cysts were present in the lung parenchyma. Further studies additionally revealed bilateral subsegmental pulmonary emboli, acute deep venous thrombosis of the left femoral vein, and takotsubo cardiomyopathy. As the patient’s mental status improved, she was found to have left-sided hemiparesis and hemineglect. While initial head imaging was negative for stroke, day 3 brain MRI showed interval development of bilateral MCA infarcts in watershed distribution. Transcranial Dopplers showed a Spencer grade 5 shunt with Valsalva and repeat TTE with bubble was consistent with patent foramen ovale. The patient was successfully extubated, discharged to a stroke rehab facility, and experienced full recovery of her neurologic deficits. Elective excision of the lung lesion with thoracic surgery revealed pathology consistent with bronchogenic cyst. Discussion This is a case of a patient who suffered from presumed intracranial air embolism due to expansion of a previously undiagnosed cystic lung lesion during a commercial flight. While the risk of air travel-related pneumothorax in patients with cystic lung disease is well described, intracranial air embolism is incredibly rare, with only a few prior reported cases in the literature. On ascent, the decrease in atmospheric pressure causes an increase in gas volume, leading to expansion of the lesion with damage to local pulmonary vasculature and subsequent air entrainment. Due to rapid reabsorption of air, the initial air embolus is often not seen on initial head imaging, but brain MRI can show infarcts in a watershed distribution. Complicating this particular case is the concomitant presence of DVT and patent foramen ovale, raising the question of whether paradoxical thrombus also contributed to the patient’s strokes. This abstract is funded by: None
Lieberman et al. (2026) studied this question.