Inhaling helium to produce that amusing squeaky voice may not be the innocuous party trick it seems, according to emergency medicine physicians at the Wesley Center for Hyperbaric Medicine in Brisbane, Australia (Ann Emerg Med 2000;35:300-303).
Simon Mitchell and colleagues report the case of a previously healthy 27-year-old man who inhaled helium and subsequently developed a stroke with transient blindness and radiographic evidence of cortical infarction. The man had inhaled the gas directly from a pressurized canister; most children who perform the trick—to imitate the voice of Mickey Mouse—inhale the gas from helium-filled balloons.
The patient developed rigidity and lost consciousness within moments of inhaling the helium. On arrival at the emergency room 15 minutes later, he regained consciousness but was found to have complete visual loss and evidence of cortical infarction.
The patient was diagnosed with a cerebral arterial gas embolism occurring after inhaling helium; he was treated with hyperbaric oxygen. His blindness resolved, and there was radiographic evidence of regression of his stroke after four cycles of treatment with hyperbaric oxygen.
The patient in this report had inhaled helium from a high pressure cylinder, causing blood vessels in his lungs to rupture and allowing the gas to gain access to the pulmonary vasculature and subsequently to his brain. Before inhaling helium, the patient had consumed alcohol, smoked marijuana, and taken an amphetamine. These factors may have lowered his threshold for the stroke but did not cause it.
This is the second reported case of stroke occurring after helium inhalation. The first occurred in a 13-year-old boy and showed that even a single breath of helium can lead, albeit rarely, to stroke.
Figure 1.
Helium: safe in balloons but not in lungs?