During scuba diving, nitrogen dissolves into the body tissues due to elevated pressure under water. During a sudden drop in pressure due to a rapid return to the water surface, arterial gas embolism can arise from pulmonary barotrauma. In a later phase, nitrogen bubbles can also arise in the venous circulation (decompression sickness). Arterial bubbles can incur vascular damage, obstruction, hypoxia and infarction.A 53-year-old healthy sport diver presented at the emergency department in a hypovolemic shock with progressive paresis of all the extremities. He had made an emergency ascent from a depth of 47 meter. During recompression therapy his condition deteriorated. It transpired that he had an patent foramen ovale. As a consequence of this, nitrogen bubbles due to decompression sickness entered the arterial circulation. Despite maximum therapeutic intervention the patient remained paretic.After an ill-fated dive, this patient with patent foramen ovale contracted arterial gas embolism due to pulmonary barotrauma and, at a later stage, decompression sickness. There was increasing damage to the spinal cord resulting in severe physiological disruption.