The concussion from shell blasts could stop a man's heart or rupture internal organs, so that he died with no obvious external trauma. But, it could also result in a most literal form of shell shock. Autopsies on soldiers who were later killed after receiving treatment for shell shock related to ordnance explosions showed that the earlier shell concussion had caused non-fatal neurological damage from tiny hemorrhages in the brain and central nervous system. Of course, men could exhibit similar symptoms even when they had not been exposed to shell fire. In 1916, a distinction started being made between those who were shell shock wounded (W) and shell shock sick (S).