Pneumomediastinum and pneumorrhachis from recreational nitrous oxide inhalation: no laughing matter

A 16-year-old girl with no medical history presented to our emergency department with rapid onset and progressive facial and neck swelling, dyspnoea and dysphonia. CT scan of the neck, chest and abdomen without intravenous contrast confirmed the presence of extensive subcutaneous gas within the face, neck and thorax, including pneumomediastinum, pneumopericardium and small bilateral pneumothoraces ( figure 1 ). A widely used method for recreational consumption involves decanting the contents of the pressurised canister into a balloon, presumably to allow controlled administration in small aliquots.