THE DISTRIBUTION OF LIMB PAIN IN DECOMPRESSION-SICKNESS

Background: For many years there has been a widely held but largely un substantiated belief that pain in the upper limb in decompression sick ness (DCS) is associated with bounce diving, whereas compressed air wo rkers, saturation divers and high altitude aviators are more susceptib le to involvement of the lower limbs. Hypothesis: The hypothesis of co unter current exchange of inert gas, modulated by changes in tissue te mperature, has been evaluated as a possible mechanism to explain the r eported distribution of limb pain in DCS. Methods: An extensive review of over 19,000 cases of limb pain decompression illness has been unde rtaken from case reports stored in the diving accident database at the Institute of Naval Medicine, in the published literature, and from un published clinical and experimental reports. Results: There was a pred ominance of upper limb involvement in bounce divers and, in contrast t o traditional teaching, in aviators. By contrast, the lower limbs were more commonly involved in compressed air workers and saturation diver s. Conclusion: Each of the occupational exposures has been discussed i ndividually with reference to counter-current exchange and other facto rs as potential influences on the distribution of disease. We conclude that counter-current exchange of inert gas may be implicated in the d istribution of limb pain in DCS.