[Idiopathic medullary decompression sickness: myth or reality?].

Severe decompression sickness occurs unfrequently, with, generally an identifying cause (error in decompression protocols, promoting factors.). We report a case of severe spinal cord damage; onset after a common dive, neither deep nor long, without any promoting factor, absence of responsiveness to recompression, three hours post-dive, importance of MRI signal abnormalities, make us to point out the confounding variability of onset and evolution of such illness.