decompression sickness, also called caisson workers' disease and the bends, is the most well-known complication of scuba diving. it occurs as divers ascend, and often from ascending too fast or without doing decompression stops. bubbles are large enough and numerous enough to cause physical injury. it is quite possible that all divers have microbubbles in their blood to some extent, but that most of the time these bubbles are so few and so small that they cause no harm. when dcs occurs, bubbles disrupt tissues in the joints, brain, spinal cord, lungs, and other organs. symptoms vary enormously. dcs may be as subtle as unusual tiredness after a dive, or an aching elbow, or a mottled skin rash. or, it may present dramatically, with unconsciousness, seizures, paralysis, shortness of breath, or death. paraplegia is not uncommon.