A diver ascends from a dive while holding their breath and later experiences confusion, dizziness, and collapses. What condition is the diver likely suffering from?

The diver is most likely suffering from an arterial gas embolism due to the scenario described. When a diver ascends while holding their breath, the air in their lungs expands as external pressure decreases. This can lead to the formation of gas bubbles in the bloodstream, especially if the alveoli expand beyond their capacity and rupture, allowing air to enter the circulatory system.

The symptoms of confusion, dizziness, and collapse that the diver experiences are characteristic of an arterial gas embolism, where the gas bubbles travel through the blood vessels to the brain and other vital organs, potentially leading to serious neurological damage or even death.

In terms of the other options, mediastinal emphysema, pneumothorax, and subcutaneous emphysema, while they do occur due to diving-related injuries, present with different symptoms. Mediastinal emphysema involves air in the central chest area and may cause chest pain or difficulty breathing. A pneumothorax involves air in the pleural space around the lungs and can cause shortness of breath and sharp chest pain, and subcutaneous emphysema pertains to air trapped under the skin, typically leading to swelling or a crackling sensation rather than confusion and dizziness like in arterial gas embolism.