A stroke of bubbles: Cerebral air embolism following accidental hydrogen peroxide ingestion in a patient with incidental atrial fibrillation.

BACKGROUND

Cerebral air embolism (CAE) is a rare but potentially devastating complication of concentrated hydrogen peroxide (H₂O₂) ingestion. Distinguishing CAE from other embolic sources is critical for appropriate acute management, especially when alternative etiologies coexist.

CASE DESCRIPTION: An 82-year-old woman presented with acute left-sided weakness after accidentally ingesting 50 mL of 35% H₂O₂. While 48-hour Holter monitoring incidentally detected paroxysmal atrial fibrillation (AFib) during the workup, brain MRI revealed a characteristic "scattered cortical pattern" of punctate diffusion restrictions across bilateral hemispheres. This non-territorial distribution, combined with a 16-mm pulmonary air cyst on CT and corrosive gastritis on endoscopy, facilitated the identification of CAE over AFib-related cardioembolism. Anticoagulation was deferred to avoid exacerbating gastrointestinal bleeding, and the patient improved with oxygen-based supportive care.

CONCLUSION

In patients with incidental embolic sources like AFib, recognizing the non-territorial punctate cortical pattern on MRI is a pivotal diagnostic clue for CAE. This distinction is essential to prevent inappropriate anticoagulation in the setting of acute corrosive mucosal injury.